Thursday, April 10, 2014

A New Approach for Repairing/Rejuvenating Damaged Photoreceptors and Other Retinal Tissue for Restoring Vision

Over the past several years, I have written about new technologies for treating retinal diseases, including the use of drugs (Avastin, Lucentis and Eylea for wet AMD), laser treatment (Ellex’s 2RT - Retinal Regeneration, for dry AMD), and the use of stem cells and gene therapy for a wide range of ophthalmic diseases.

Earlier this year, I became aware of a new company, jCyte, who was investigating the use of retinal progenitor cells to replace damaged or destroyed photoreceptors to restore vision to those whose photorecptors had stopped working, especially in those with the latter stages of  retinitis pigmentosa (RP). I was aware that Advanced Cell Technology was also in the early stages of doing research with retinal progenitor cells. I decided the best way of learning about this unique approach to restoring photoreceptor activity (and perhaps, vision) to those afflicted with RP and other retinal degenerative diseases, was to undertake some research and write about it.

In doing the background research, I discovered that two other companies, ReNeuron and California Stem Cell, are also involved in this area of technology. Here is what I have learned to date.

Introduction

In order to learn about jCyte, I contacted Dr. Henry Klassen, it’s founder and Associate Professor of the Gavin Herbert Eye Institute and its Stem Cell Research Center at the University of California, Irvine (UCI), and learned about his new company and about how its program to restore vision to those with RP will evolve.

In doing additional background research, I quickly discovered that ReNeuron, a UK biotechnology company, was also working towards that same goal and, in fact, was working with Dr. Michael Young of Schepens Eye Research Instititute who, it turned out, was a past co-author with Dr. Klassen’s in working on pre-clinical animal studies in this field.

In this writeup, I intend to tell you what retinal progenitor cells are, what they can do, and why this might be an important technique for restoring vision in those with damaged or destroyed photoreceptors.

I will also tell you about the companies involved, where the state of development stands and provide a possible timetable to the future, including the pre-clinical work underway and the road to human clinical trials.

I have also included some information about competitive activities, and where these alternative techniques/technologies for restoring vision for those with damaged photoreceptors stand.

The Problem

There is a group of  retinal degenerative diseases that constitute a significant source of visual disability in both the developed and undeveloped world, and where current therapeutic options are quite limited.

For instance, the loss of photoreceptor cells, as seen in the later stages of retinitis pigmentosa (RP), geographic atrophy (GA) in dry AMD, and the late stages of Stargardt’s disease (SMD), results in permanent visual loss for which no restorative treatment is as yet available. But, the notion that photoreceptor cells might be replaceable in therapeutic settings has been given recent support by experimental work in animal models [1].

The Technology

What are progenitor cells and what can they do?

A progenitor cell is a biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and, can be pushed to differentiate into its "target" cell. The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely whereas progenitor cells can divide only a limited number of times.

Most progenitors are described as multipotent, not pluripotent. In this point of view, they may be compared to adult stem cells, but progenitors are said to be in a further stage of cell differentiation. They are in the "center" between stem cells and fully differentiated cells. The kind of potency they have depends on the type of their "parent" stem cell and also on their niche, in this case, eye-derived progenitor cells that have partially differentiated into retinal cells.

Retinal progenitor cells (RPCs)

Retinal progenitor cells are self-renewing cells capable of differentiating into the different retinal cell types including photoreceptors (rod and cone cells), even neuron cells, and they have shown promise as a source of replacement cells in experimental models of retinal degeneration.


The Companies Involved

Advanced Cell Technology (ACT)

ACT’s primary research program uses retinal pigment epithelium (RPE) cells derived from embryonic stem cells in the treatment of dry AMD, Stargardt’s disease, and soon myopic macular degeneration (MMD). The company is currently injecting these hESC-derived RPE cells subretinally into humans in three clinical trials, in which more than 30 patients have been treated to date, with no reported problems of safety and, in most cases, with reported improved vision. In one case, a dry AMD patient reportedly went from 20/400 vision, to 20/40 vision within several weeks of treatment. [2]. We believe that in this case, his dormant (but still alive) photoreceptors were re-activated by the RPE cell treatment.

The MMD clinical trial has received IND approved and is expected to begin shortly.

The company is also undertaking early pre-clinical animal studies in their laboratories with several types of  progenitor cells.

As reported by Dr. Robert Lanza, the company’s CSO at the last shareholder’s meeting in October 2013 [3]:

 “We have, as I mentioned earlier, a number of other cell types that we are studying in the eye field, including our retinal neural progenitors, photoreceptor progenitors, and also ganglion progenitors. As regard to the retinal neural progenitors, we have looked at these cells in animals that have retinal degeneration...and we can see very significant rescue of their activity.”

“We also have a program that we are pursuing using these photoreceptor progenitors. When you inject these into animals subretinally, what we were able to actually see here in the first week...the cells incorporating into the retina and within only three weeks you can see them moving into the outer nucleated layer and integrating.”

“We are also studying the photoreceptor progenitors. We are also looking to see if we can recover visual function and retinal structure using those. We also want to test those both in vitro and in vivo in terms of using conditioned media in the secreted factors. We are also studying our ganglial progenitors and we are continuing to look at those in animals for prolonged term survival of the transplanted cells, as well as for the protection or replacement of the host ganglial cells. We are also looking at using these cells in the optic nerve regeneration model.”


Systemically delivered Photoreceptor Progenitor cells reversed the progression of photoreceptor degeneration – and promoted regeneration of both Rods and Cones.[4]

More recently, the company updated the status of its progenitor programs in its recent Form 10-K for 2013[5]:

Photoreceptor Progenitor Program

We have developed a human photoreceptor progenitor cell. We believe that our photoreceptor progenitor cells, [derived from embryonic stem cells (hESCs)], are unique with respect to both the markers they express as well as their plasticity, meaning that they can differentiate into both rods and cones, and therefore provide a viable source of new photoreceptors for retinal repair. In addition, the photoreceptor progenitors appear to secrete neuroprotective factors, and have the ability to phagocytose (digest) such materials as the drusen deposits that build up in the eyes of dry AMD patients, and so may provide additional benefits beyond forming new photoreceptors when injected into the subretinal space in the eyes of patients. We will continue our preclinical investigation in animal models, establish appropriate correlation between integration of the transplanted cells and visual function in the animals, and then consider preparation of an IND and/or IMPD application to commence clinical studies with these cells.

Retinal Ganglion Cell Progenitor Program

In the United States alone, approximately 100,000 people are legally blind from glaucoma. The only proven treatment is drug therapy or surgically lowering the intraocular pressure, but many patients lose vision despite receiving these treatments. In glaucoma, retinal ganglion cells degenerate before photoreceptors are lost. We are currently conducting pre-clinical research and development activities regarding differentiation of stem cells into retinal ganglion cells and demonstration of the ability of those cells to protect against elevated intraocular pressure in glaucoma models. We have succeeded in generating a unique human ganglion progenitor cell which, when injected in animal models of glaucoma, appear to protect against damage and to form new ganglion nerve cells. We will continue our preclinical investigation in animal models, establish appropriate correlation between integration and visual function in the animals, and then consider preparation of an IND and/or IMPD application to commence clinical studies with these cells.

Neuroprotective Biologics

In the course of our work with various progenitor cells for treating ocular degenerative diseases, we have discovered that certain progenitor cells not only have the ability to participate directly in the formation of new tissue in the eye, but also were able to exert a neuroprotective effect that reduces the rate of degeneration of native photoreceptors in the animals' eyes, for example, in animal models of macular degeneration. These cells appeared to also be a source of neuroprotective paracrine factors; biological agents which may themselves be useful as drugs. Further, we observed that these protective effects were uniquely produced by particular progenitor cell sub-types. The restriction of this protective activity to only a certain progenitor cell type permits us to examine which factors are differentially produced by these cells as compared with other closely related progenitor cells which do not seem to secrete any protective agents. We anticipate that the neuroprotective agent(s) that we may ultimately develop as drug candidates may be useful not only in retinal diseases and dystrophies, but may have broader applications in central nervous system and peripheral nervous system diseases and disorders, including diseases causing cognitive function impairment, movement disorders such as Parkinson's Disease, and ischemic events such as caused by stroke.

This progenitor cell work is in the pre-clinical stages and not yet ready for human clinical testing.


Californis Stem Cell, Inc. (CSC)

In early February, California Stem Cell, Inc. (CSC) announced the initiation of a collaborative study with the University of California, Irvine (UCI), to create a transplantable 3D retinal tissue.[6] The study, funded by a $4.5 million grant from the California Institute of Regenerative Medicine (CIRM), is a continuation of methods pioneered by CSC scientists and researchers at UCI in 2010 [7], and will investigate the potential of improving a patient's visual function by transplanting human stem cell-derived three-dimensional (3D) retinal tissue into their retina.

California Stem Cell, using its specialized cGMP manufacturing facility and regulatory personnel, will differentiate human stem cells into retinal progenitor cells. These cells will then be co-cultured with stem cell-derived retinal pigment epithelium to create a 3D tissue structure suitable for transplantation. Proof of concept in-vivo studies will take place at UCI's Sue & Bill Gross Stem Cell Research Center, under the auspices of Dr. Magdalene J. Seiler. Transplants are expected to develop into mature retina, interact with the host tissue, and subsequently improve the vision of retinal degenerative recipients. The study, if successful, could lead to new treatments for incurable retinal diseases such as retinitis pigmentosa and age-related macular degeneration, leading causes of vision loss for people age 50 and older.

CSC President & CEO Hans Keirstead, Ph.D. (formally with UCI) will lead the study's work at CSC. "This study establishes a valuable partnership between ourselves and a team of very talented scientists at a university known for its excellence in research," said Keirstead. "California Stem Cell looks forward to making a meaningful contribution to work that has the potential to help millions suffering from life-altering retinal diseases."

This work is in the very early pre-clinical animal testing stages.

Editors Note: In late breaking news, it was announced on April 14th that CSC has been acquired by NeoStem, Inc. The deal is expected to close in May.


jCyte

jCyte has developed methods, that utilize human, fetal-derived, retinal progenitor cells (hRPCs), that have been partially developed into retinal cells, to activate degenerating host photoreceptors and replace and/or reactivate, in this case the cones, lost to disease, in those with retinitis pigmentosa (RP).

JCyte’s work will initially target cone cells because they provide central vision and the ability to read, drive and recognize faces. (Although, rod cells should also be affected.) The work will include growing pharmaceutical-grade progenitors, testing them for safety and efficacy in animal models, and then launching a clinical study for severely impaired RP patients, to prove safety and efficacy in humans.

jCyte's research is currently supported by several resources including The Discovery Eye Foundation and two awards from CIRM (the California Institute for Regenerative Medicine), including a $4 million CIRM's Early Translation II Award [8] and more recently a $17 million Therapy Development grant [9]. Dr. Klassen's project was also accepted into the Therapeutics for Rare and Neglected Diseases (TRND) program established by the National Institutes of Health to speed the development of new treatments for rare and neglected diseases. TRND will provide him with specialized expertise and resources to help advance his efforts [10].

Dr. Klassen intends to seek further funding to translate this cutting-edge discovery into clinical drug and cell therapy, via submission to the FDA to launch a clinical trial.

In an update posted on his website in November 2013 [11], Dr. Klassen reported that, “The team remains hard at work in the effort to bring retinal progenitor cells to clinical trials. The work being conducted now is centered on accumulating the evidence we need to provide to the FDA in order to get approval. Prior work has set the stage by showing what is possible using these cells, but now everything has to be repeated on a larger scale, with extensive documentation, and using the same cells that will be used in patients. This is known as the Pre-Clinical Phase of the project and, as such, it is the stage just before trials begin. The major objective of the Pre-Clinical Phase is to demonstrate safety and efficacy of the product in animal models as a basis for initiating studies in humans. It is a lot of work and would take a long time if everything was done sequentially so, with the help of CIRM, we are approaching the various projects in parallel to accelerate progress. Still, it can be expected to take about a year to complete. As the results of theses studies come in, they will be collected to form the body of what is known as an Investigational New Drug (IND) application, which is the formal document that goes to the FDA.”

If things go as planned, jCyte should complete its pre-clinical work and be prepared to submit its NDA by late 2014, for a human clinical trial for patients with severe RP. The patients will be injected with hRPCs in their worst-seeing eye to determine safety and efficacy, hopefully, beginning sometime in early 2015.

Other targeted conditions, once safety and efficacy are shown in the RP trial, could include geographic atrophy (GA) found in dry AMD, and replacing destroyed photoreceptors in those suffering from Stargardt’s Disease (Stargardt’s Macular Dystrophy [SMD]).


ReNeuron

One of the more ambitious stem-cell treatments nearing human study is being developed by ReNeuron, a company from the United Kingdom. Its retinal progenitor treatment replaces photoreceptors lost to retinitis pigmentosa. When transplanted in the retina, ReNeuron researchers believe that the partially developed cells will mature into fully functional photoreceptors. The company hopes to launch a clinical trial this year. Previously funded by the Foundation Fighting Blindness, Michael Young, Ph.D., of Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, conducted much of the research making this treatment approach possible. His work included the development of a biodegradable scaffold for growing and organizing the cells prior to transplantation. The structure increases the chances of survival and integration of the therapeutic cells.[12]

In September 2013 [13], ReNeuron was granted an orphan designation by the U.S. Food and Drug Administration (FDA) and the European Commission for its emerging retinitis pigmentosa (RP) treatment, known as ReN003 (hRPCs derived from fetal tissue). Given to potential treatments for rare conditions that are life-threatening or chronically debilitating, "orphan" status provides a company with development incentives, tax credits and market protections for therapy development.

The designation bolsters ReNeuron's plan to launch a Phase I/II clinical trial for ReN003 in mid-2014. The company is partnering with the Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, to develop the treatment. According to Dr. Young, a lead investigator on the project at Schepens, ReNeuron plans to initiate the study at the Mass Eye & Ear Infirmary in the United States, and later extend it to sites in Europe.


Other Research Programs:

There are also several university-based projects underway, including that of Prof. Robin Ali at University College London [14], and in the lab of Thomas Reh at the University of Washington in Seattle [15].

Competing Technologies for Restoring Vision to Those with Damaged/Destroyed Photoreceptors

In addition to the programs using retinal progenitor cells, there are several efforts underway to provide vision to those who have lost it because of damaged or destroyed photoreceptors.

I will list just a few of these:

The Use of Stem Cells – Several companies/institutions are in clinical trials [16] using stem cells to treat those with Stargardt’s disease, dry AMD, and retinitis pigmentosa.

The Use of Gene Therapy – Gene therapy is also actively being used [17] in the treatment of dry (and wet) AMD, Stargardt’s disease, and retinitis pigmentosa.

Optogenetics – An offshoot of gene therapy, wherein a photoactive dye is delivered via a virus carrier into neural tissue (ganglion cells, bypassing damaged photoreceptors) and is activated by light signals sent into these activated tissues, which in turn sends electrical signals along the optic nerve to the brain [18]. Several companies and institutions are currently doing animal work in preparation for undertaking human trials, including Eos Neuroscience, Gensight Biologics, RetroSense Therapeutics, and the Institute de la Vision in Paris [19], along with work being done at Cornell Univ. by Dr. Sheila Nirenberg [20].

Retinal Implants – Several companies have developed and are currently marketing devices that sit on the surface of the retina and use cameras, or other optical means to send a signal to the electrodes implanted on the retinal surface that in turn sends a signal to the brain simulating visual inputs [21].

Retinal Regeneration – a laser treatment whereby a mild laser dose is imposed onto the RPE layer as a means of “stimulating” the RPE cells to release enzymes that are capable of “cleaning” Bruchs membrane, thereby rejuvenating the retina and restoring vision [22].


Commentary

I personally believe that the use of retinal progenitor cells to rejuvenate or repair damaged photoreceptor cells in those people with degenerative retinal diseases, is an important step in the right direction. If, in the clinical trials scheduled to begin in late-2014 or 2015, this technique does restore vision in people that have lost it due to damaged or destroyed photoreceptors, it will become one of the great advances in the battle of fighting blindness.




References:





5. ACT Form 10-K, April 1, 2014


7. Three-dimensional early retinal progenitor 3D tissue constructs derived from human embryonic stem cells, Gabriel Nistor et al, Journal of Neuroscience Methods, April 2010.



Henry J. Klassen, M.D., Ph.D.,, Therapeutics for Rare and Neglected Diseases(TRND) program at the NIH's National Center for Advancing Translational Sciences (NCATS), October 2, 2013

11. November 2013 Update from Dr. Henry Klassen, jCyte News, November, 2013

12. Several New Stem Cell Clinical Trials Poised to Begin in Two to Three Years, Dr. Stephen Rose, Eye on the Cure (FFB), July 12, 2013


14. New Breakthrough: transplantation of photoreceptors from retina grown `in a dish', Prateek Buch, UCL EyeTherapy blog, July 22, 2013

15. Efficient generation of retinal progenitor cells from human embryonic stem cells, Lamba et al, University of Washington, Seattle, WA,  PNAS, July 2006




19. Gene Therapy Companies/Institutions Active in Ophthalmology, Irv Arons’ Journal, January 2014


21. Ibid, section on Retinal Prostheses

22. Ellex 2RT Updated Clinical Results: ARVO 2011, Irv Arons’ Journal, May 2011





Monday, March 10, 2014

Reversing Retinal Cell Death With Inkjet Printing?

For the past several months, I have been working with Mark Hillen, the editor of The Ophthalmologist, in providing him with background information about stem cells and gene therapy used in ophthalmology to treat various retinal diseases. Articles, based on my information, along with material developed by Mark, have been published in past issues of his magazine. (Stem Cell Clinical Trials and Gene Therapy Clinical Trials.)

The Ophthalmologist is a new professional journal, published by Texere Publishing, for a target audience of ophthalmologists and industry professionals, mainly based in Europe.

The latest issue (February 2014) contains an interesting interview with Keith Martin, Professor of Ophthalmology at the University of Cambridge, about how he and his colleagues have adapted an inkjet printer to be capable of printing live retinal ganglion and glia cells that someday, might be used to treat and reverse retinal diseases.

With the permission of The Ophthalmologist, here is their story:


Can you envisage a future in which deploying a tiny cell-spraying device during vitreoretinal surgery reverses years of retinal cell death? Keith Martin can.

By Mark Hillen, Editor
The Ophthalmologist, February 12, 2014

When a man tells you that, in ten years' time, he envisages treating retinal diseases with a tiny inkjet printer head, you begin to wonder if he's been drinking strong coffee with too much gusto that morning. But if that man is Keith Martin, Professor of Ophthalmology at the University of Cambridge, you need to revisit that diagnosis.

Martin has the only inkjet printer in the world that can print retinal ganglion cells (RGCs) and glia, and deliver a live product. He and colleagues Barbara Lorber, Wen-Kai Hsiao and Ian Hutchings recently published the method in Biofabrication (1), and it's a story of happenstance, cross-pollination of ideas, and just giving things a go. Conventional wisdom had it that the cells of the rat central nervous system (CNS) are too fragile to be fired down a piezoelectric printer head; that printed glia wouldn't function to provide support and nutrition to neurons, and that printed RGCs wouldn't grow neurites (which are essential to communicate with other cells). Martin and colleagues did the experiments anyway. And they worked.

As loss of certain retinal cell types is characteristic of many eye diseases, from age-related macular degeneration to glaucoma, the possibility of replacing them with cultured cells that function in situ is exciting. We spoke to Martin about it.

How did this project come about?

Barbara has been working in my lab for a number of years, trying to get RGCs to regenerate but this particular project was pure opportunism. Basically, it stems from a conversation with her husband, who works on inkjet printing technology, on the overlap between what we do and what he does. It turned into a Friday afternoon experiment: they decided to see if the cells could survive the printing process. Much to everyone's surprise, they did. So it started there.

Has this been done with CNS cell types before?

There are no reports in the literature of adult CNS cell printing being achieved successfully, so this is a first - we don't know how many people have tried and failed.

How exactly was it done?

The technique that we've developed involves separating adult retinal cells and loading them into a specially built piezoelectric inkjet printing device. (See illustration.) This allows us to fire cells out of the print head (Figure 1) at about 30 mph, that's about a thousand cells per second, and we can print them in precise patterns (Figure 2). This potentially gives us a way to recreate adult neuronal structures using printing technology.



                                        Inkjet Setup

Figure 1. Retinal Cell Printing. Image sequences of (a) retinal cells and (b) purifed glial cells as they are ejected from the nozzle, labeled with image capture time (1).

Figure 2. Photomicrographs of ßIII tubulin (a marker of retinal ganglion cells - red colour) and Vimentin+ (a marker of glia - green colour) in cell cultures from: control retinal cells (a),(d), printed retinal cells (b),(e) and control retinal cells plated at the same number as the printed retinal cells (c),(f), either on their own (g)-(i) or with the retinal cells additionally having been plated on (j) control glia, (k) printed glia or (l) control glia plated at the same number as the printed glia (1). Scale bar: 50 µm.

(Open in a new tab to enlarge each of the figures and the illustration above.)

Is the goal to produce a retina that you can implant into a patient to replace a damaged one?

Well, that's a long way off. There are a number of more immediate ways that this might be useful. For example, printing retinal pigment epithelial (RPE) cells or photoreceptors, cell types that are lost specifically in certain conditions. One could envisage using the printing technology to create an implant outside the eye and then inserting it. With further miniaturization, it may be possible to spray cells within the eye, as part of vitreoretinal surgery. That's what we're looking to do, but it is far too early to talk about achieving it.

Might the optimal combination be a retinal prosthesis sensor and appropriate printed cells around it?

Yes. I think the biggest advances will come not from using one of these technologies alone, but by combining them, coming at the problem from different approaches. The interface between the electronic and the biological approaches is one such combination.

Ultimately do you plan to build a retina? If so, what's the scaffold that you'll build it on - glia? Do other cell types, like those of the vasculature need to be incorporated?

We're certainly looking at other cell types. Glial-neuronal interactions are obviously very important for the health of neurons - they can't function in the long term without the support of glia. In terms of regeneration, the glial effect really promotes the axonal regeneration; we saw far better axon regeneration from the RGCs.

We are a long way from being able to replicate the vasculature. But there are other ways of stimulating blood vessel growth. In degenerative diseases, the blood supply is not so much of a problem. For ischemic conditions it might be, but we're sticking to the neurons and glia just at the moment.

In a decade's time, where do you think this technology will be?

We'd like to be using this as part of the treatment for regenerating the retina - that's our main goal. As I said, I don't think that this is the whole solution but it will help. We will look at manufacturing artificial neuronal tissue and also at repairing what's already there.

Will it be in clinical trials in 10 years' time?

Yes, that's the timescale we're looking at. In terms of printing RPEs and photoreceptors it might even be a bit quicker than that, as those are more straightforward cell types. We started in RGCs because my main interest is in glaucoma - a crucial element in the pathophysiology of all forms of glaucoma is RGC death. However, people who have looked at the work are saying that it may well be more relevant to replacing RPE and photoreceptors.

What about the cornea? Could you repair selectively damaged areas with inkjet cell technology?

I think that's perfectly possible, and it may well be easier than the neuronal cell types. I'm not sure anyone has tried as yet. This is a very adaptable and modifiable technology and if fragile neurons can survive it, then I'm sure that corneal cells will.


Barbara Lorber
Keith Martin















Reference

"Adult rat retinal ganglion cells and glia can be printed by piezoelectric inkjet printing", B. Lorber et al., Biofabrication, 6, 015001 Epub ahead of print] (2013). doi:10.1088/1758-5082/6/1/015001.


Abstract

We have investigated whether inkjet printing technology can be extended to print cells of the adult rat central nervous system (CNS), retinal ganglion cells (RGC) and glia, and the effects on survival and growth of these cells in culture, which is an important step in the development of tissue grafts for regenerative medicine, and may aid in the cure of blindness. We observed that RGC and glia can be successfully printed using a piezoelectric printer. Whilst inkjet printing reduced the cell population due to sedimentation within the printing system, imaging of the printhead nozzle, which is the area where the cells experience the greatest shear stress and rate, confirmed that there was no evidence of destruction or even significant distortion of the cells during jet ejection and drop formation. Importantly, the viability of the cells was not affected by the printing process. When we cultured the same number of printed and non-printed RGC/glial cells, there was no significant difference in cell survival and RGC neurite outgrowth. In addition, use of a glial substrate significantly increased RGC neurite outgrowth, and this effect was retained when the cells had been printed. In conclusion, printing of RGC and glia using a piezoelectric printhead does not adversely affect viability and survival/growth of the cells in culture. Importantly, printed glial cells retain their growth-promoting properties when used as a substrate, opening new avenues for printed CNS grafts in regenerative medicine.


Saturday, January 18, 2014

Laser Refractive Keratoplasty: The Rest of the Story

In 1989, I wrote a paper published by Arthur D. Little, A White Paper - The Evolution and Prospects for Laser Refractive Keratoplasty. This was the first paper I wrote on the potential for (at that time) LRK, now known as PRK, that later turned into LASIK. It provides a comprehensive look at the early history of refractive surgery as I knew it.

Last December, I learned of an article based on a press release put out by the Optical Society of America (OSA), that described the invention of using the excimer laser to ablate human tissue in the laboratories of IBM. (It turns out the OSA put out publicity about the article, because of its connection to Thanksgiving, as you will see below.)

The article will be part of a book that the OSA is publishing in 2016 to celebrate its 100th Anniversary. The book will capture the history of the Optical Society in the context of the evolution of optics research and the optics industry as well as changes in the nature of the science and technology enterprise and, even more broadly, changes in the United States and the world.

In reading the article, written by Dr. James Wynne, the manager of the IBM's Watson Research Center laboratory, where the research took place, I realized that it was the first part of the story that I had told in my White Paper, noted above. I also realized that I had a connection with Dr. Wynne, who it turns out is a relative of a close friend of mine. So, I reached out to Dr. Wynne to get his approval to use excerpts from his article to provide the beginnings of how laser refractive surgery, using the excimer laser, really began, i.e., the “rest of the story”.

So, here in Dr. Wynne’s own words, is how the excimer laser was first used in ablating human tissue and became the device to use in performing PRK (surface ablation of the cornea, including the epithelium), at first, and then LASIK (mechanical or femtosecond laser formation of an epithelium flap followed by ablation of the corneal stromal surface) today.


Excimer Laser Surgery – Laying the Foundation for Laser Refractive Surgery
James J. Wynne, Ph. D.

The discovery of excimer laser surgery

On November 27, 1981, the day after Thanksgiving, Dr. Rangaswamy Srinivasan brought leftovers from his Thanksgiving dinner into the IBM Thomas J. Watson Research Center, where he irradiated turkey cartilage with ~10-nsec pulses of light from an argon fluoride (ArF) excimer laser. This irradiation produced a clean-looking “incision” in the cartilage, as observed through an optical microscope. Subsequently, Srinivasan and his IBM colleague, Dr. Samuel E. Blum, team carried out further irradiation of turkey cartilage samples under controlled conditions, measuring the laser fluence and the number of pulses used to produce the incisions. Srinivasan gave a sample to me, and, for comparison, I irradiated it with ~10-nsec pulses of 532-nm light from a Q-switched, frequency-doubled, Nd:YAG laser. This irradiation did not incise the sample; rather it created a burned, charred region of tissue.

Srinivasan, Blum and I realized that we had discovered something novel and unexpected, and we wrote an invention disclosure, completed on Dec. 31, 1981. Our disclosure described multiple potential surgical applications, on hard tissue (bones and teeth) as well as soft tissue. We anticipated that the absence of collateral damage to the tissue underlying and adjacent to the incision produced in vitro would result in minimal collateral damage when the technique was applied in vivo. The ensuing healing would not produce scar tissue. We recognized that we had a laser surgical method that was a radical departure from all other laser surgical techniques that had been developed since the operation of the first laser on May 16, 1960. Rather than photocoagulating the irradiated tissue, the excimer laser was ablating a thin layer of tissue from the surface with each pulse, leaving negligible energy behind, insufficient to thermally damage the tissue underlying and adjacent to the incised volume. This insight was unprecedented and underlies the subsequent application of our discovery to laser refractive surgery.

Background to this discovery

Since 1976, as manager of the Laser Physics and Chemistry department of IBM’s T. J. Watson Research Center, one of my responsibilities was to ensure that we had access to the best and latest laser instrumentation. Earlier, I had used a nitrogen laser, emitting short pulses of ultraviolet light at 337-nm, to pump fluorescent dyes that emitted visible and near infrared light, which he used for laser spectroscopic studies. When the excimer laser, a higher-power, pulsed source of ultraviolet radiation became commercially available, I purchased a unit for use by the scientists in my department. Srinivasan had devoted his entire research career since 1960 to study the action of ultraviolet radiation on organic materials, e.g., polymers. In 1980, he and his technical assistant, Veronica Mayne-Banton, discovered that the ~10-nsec pulses of far ultraviolet radiation from the excimer laser could photoetch solid organic polymers, if the fluence of the radiation exceeded an ablation threshold.

Since organic polymers proved susceptible to etching by the excimer laser irradiation, we reasoned that an animal’s structural protein, such as collagen, which contains the peptide bond as the repeating unit along the chain, would also respond to the ultraviolet laser pulses. We knew that when skin was incised with a sharp blade, the wound would heal without fibrosis and, hence, no  scar tissue. Conceivably, living skin or other tissue, when incised by irradiation from a pulsed ultraviolet light source, would also heal without fibrosis and scarring.

Next steps

To develop practical innovative applications from our discovery, it was clear that we had to collaborate with medical/surgical professionals. In order to interest these professionals, we etched a single human hair by a succession of 193-nm ArF excimer laser pulses, producing a SEM micrograph (Fig. 1), showing 50-ƒÝ-wide laser-etched notches.

Fig. 1 – Scanning electron micrograph of a human hair etched by irradiation with an ArF
excimer laser; the notches are 50 ƒÝ wide.

While IBM Intellectual Property Law was preparing a patent application, we were constrained from discussing our discovery with people outside IBM. But we had a newly hired IBM colleague, Ralph Linsker, with an M.D. and a Ph. D. in physics. Linsker obtained fresh arterial tissue from a cadaver, and we irradiated a segment of aorta with both 193-nm light from the ArF excimer laser and 532-nm light from the Q-switched, frequency-doubled Nd:YAG laser. Once again, the morphology of the tissue adjacent to the irradiated/incised regions, examined by standard tissue pathology techniques, was stunningly different, with irradiation by the 193-nm light showing no evidence of thermal damage to the underlying and adjacent tissue.

This experimental study on freshly excised human tissue confirmed that excimer laser surgery removed tissue by a fundamentally new process. Our vision--that excimer laser surgery would allow tissue to be incised so cleanly that subsequent healing would not produce scar tissue--was more than plausible, it was likely, subject to experimental verification on live animals.

First public disclosure


After IBM filed our patent application on December 9, 1982, we were authorized to publicly disclose our discovery. We wrote a paper and submitted it to Science magazine, but it was rejected, because one of the referees argued that the irradiation of living humans and animals with far ultraviolet radiation would be carcinogenic, making our laser surgical technique more harmful than beneficial. Since Srinivasan now had an invitation to give a presentation about his work on polymers at the upcoming CLEO 1983 conference in Baltimore, MD, co-sponsored by the Optical Society of America, we wanted to get a publication into print as soon as possible, so we resubmitted our paper to the trade journal Laser Focus, including some remarks about the new experiments on human aorta. Serendipitously, the Laser Focus issue containing our paper was published simultaneously with CLEO 1983, where, on May 20, Srinivasan gave an invited talk entitled “Ablative photodecomposition of organic polymer films by far-UV excimer laser radiation.” In this talk, he gave the first oral public disclosure that the excimer laser cleanly ablated biological specimens as well as organic polymers.

From excimer laser surgery to ArF excimer laser-based refractive surgery

At this very same CLEO 1983 meeting, on May 18, Stephen Trokel and Francis L’Esperance, two renowned ophthalmologists, gave invited talks on applications of infrared lasers to ophthalmic surgery. I attended both of their talks and was amazed at the results they obtained in successfully treating two very different ophthalmic conditions. I was well aware that the ruby laser was first used to eradicate a retinal lesion in late 1961, and retinal surgery with lasers had become widespread in the ensuing two decades, in particular to repair retinal tears and to treat diabetic retinopathy. But these treatments required a laser at a wavelength for which the ocular media anterior to the retina was transparent. Excimer laser light would be absorbed in a thin layer upon entering the cornea, so the excimer laser would be useless for treating retinal maladies.

But Trokel knew of ophthalmic conditions, such as the refractive imperfection known as myopia, that could be corrected by modifying the corneal curvature. A treatment known as radial keratotomy (RK), developed in the Soviet Union and being practiced in the United States, corrected myopia by using a cold steel scalpel to make radial incisions at the periphery of the cornea. When these incisions healed, the curvature of the front surface of the cornea was reduced, with the consequence that the patient’s myopia was also reduced. The technique could rarely give the patient uncorrected visual acuity of 20/20, but the patient’s myopia was definitely reduced. One serious drawback of RK was that the depth of the radial incisions left the cornea mechanically less robust, and the healed eye was more susceptible to “fracture” under impact, such as might occur during an automobile collision. Trokel speculated that the excimer laser might be a better scalpel for creating the RK incisions.

Upon learning of our discover of excimer laser surgery, Trokel, who was affiliated with Columbia University’s Harkness Eye Center in New York City, contacted Srinivasan and subsequently brought enucleated calf eyes (derived from slaughter) to our IBM Research Center on July 20, 1983. Srinivasan’s technical assistant, Bodil Braren, participated in an experiment using the ArF excimer laser to precisely etch the corneal epithelial layer and stroma of these calf eyes. The published report of this study is routinely referred to by the ophthalmic community as the seminal paper in laser refractive surgery.

To conduct studies on live animals, the experiments were moved to Columbia’s laboratories. Such experiments were necessary to convince the medical community that living cornea etched by the ArF excimer laser does not form scar tissue at the newly created surface and the etched volume is not filled in by new growth. The first experiment on a live rabbit in November, 1983, showed excellent results in that, after a week of observation, the cornea was not only free from any scar tissue, but the depression had not filled in. Further histological examination of the etched surface at high magnification showed an interface free from detectable damage.

L’Esperance, also affiliated with Columbia’s Harkness Eye Center, thought beyond RK and, in November, 1983, filed a patent application describing the use of excimer laser ablation to modify the curvature of the cornea by selectively removing tissue from the front surface, not the periphery, of the cornea. His U.S. Patent No 4,665,913 specifically describes this process, which was later named photorefractive keratectomy (PRK).

Soon ophthalmologist around the world, who knew of the remarkable healing properties of the cornea, were at work exploring different ways to use to excimer laser to reshape the cornea.  From live animal experiments, they moved to enucleated human eyes, then to blind eyes of volunteers, where they could study the healing. Finally, in 1988, a sighted human was treated with PRK (Editors Note: by Dr. Marguerite McDonald at LSU), and after the cornea had healed by epithelialization, this patient’s myopia was corrected.


To read the complete article written by Dr. Wynne, including his footnotes, please follow this link.

Tuesday, November 19, 2013

AMD Update 25: Results of The AREDS2 HOME Study of Notal Vision’s Home Monitoring Device for AMD Announced

In April of 2010, I wrote about the inclusion of Notal Vision’s ForseeHome AMD Monitor in the AREDS2 clinical trial.

The overall objective of the two arm randomized clinical trial was to determine if home monitoring of participants at high risk of progression from late-stage dry AMD to neovascular AMD, using the comprehensive visual field and telemedicine solution based on the ForeseeHome Device in AREDS2 (referred to as the ForeseeHome comprehensive solution), would improve detection of progression to choroidal neovascularization (CNV) when compared with standard care (may have included use of the Amsler Grid).

Well, the results are in and the National Institute of Health (NIH) found that patients at high-risk for developing neovascular age-related macular degeneration would benefit from using the ForeseeHome Monitoring device for early detection of their CNV.

Report Represents the Most Comprehensive Study of Home Monitoring for Progression of AMD

As reported at the Retinal Subspecialty Meeting at this year’s AAO Meeting, the results of the Home Monitoring of the Eye (HOME) study, conducted in Age-Related Eye Disease Study 2 (AREDS2) clinical centers showed that participants at high risk for developing choroidal neovascularization (CNV) using the ForeseeHome monitoring device strategy had significantly better preservation of their visual acuity at the time of CNV detection than the control group of participants who were only using standard care methods (the Amsler grid) to self monitor their AMD for progression. The study's Data Safety and Monitoring Committee recommended early termination of the study on April 2, 2013 based on superior vision outcomes among the participants randomly assigned to use the home device.

The AREDS2 HOME Study was a collaborative effort led by the National Eye Institute to evaluate the performance of a home monitoring device plus standard care compared to standard care monitoring alone for the detection of AMD progression to the neovascular phase. Standard care methods included periodic monocular self checks of vision clarity, blind spots and distortion, which included use of an Amsler grid. As treatments to manage the neovascular phase of AMD have improved, the importance of early detection of this event has increased in an effort to optimize outcomes following treatment of neovascular AMD. Approximately 8 million individuals in the United States, age 50 and older, are estimated to have intermediate (large drusen) or advanced dry AMD in one eye, placing them at high risk of progression to neovascular (wet) AMD (CNV), ranging from 25 to 50% over a five-year period.

Results of the HOME Study and Implications for AMD Management

At the time of CNV detection, 87% of eyes in the ForeseeHome device arm maintained visual acuity of 20/40 or better compared to 62% in the standard care alone arm. Median acuity among device users at the time of CNV diagnosis was 20/32. Among participants who used the device at the recommended minimum frequency (twice per week) to monitor their AMD for progression, 94% of eyes that progressed to CNV maintained 20/40 or better visual acuity. When CNV was detected, participants in the ForeseeHome device arm lost fewer letters on visual acuity testing (median loss of 4 letters) from entry levels of vision at the start of the study compared to those in the standard care alone arm (median loss of 9 letters). Use of the ForeseeHome device resulted in an increase in the proportion of CNV events first identified at home, meaning in between routine ophthalmic office visits to assess detection of disease progression. Among individuals using standard care methods for monitoring, only 55% of those that progressed noted symptoms at home that led them to present for examination; whereas 80% of the participants in the device monitoring group returned sooner than a scheduled visit because a change was noted by the device or by self-monitoring. This was associated with a greater degree of vision preservation at CNV diagnosis among individuals who returned promptly for changes, as the median visual acuity loss at CNV detection was 3.0 letters for those in the device arm compared with 11.5 letters for those in the standard care group. The average annual rate of false alerts among the device users, reported as the annual false positive rate, was 0.24 alerts/year, which may be extrapolated to one false alert on average every 4.2 years for each ForeseeHome user.

"Persons 60 years of age or older should undergo dilated eye examinations to determine their risk of developing advanced AMD, especially CNV," said Jeffrey S. Heier, MD, Director of the Vitreoretinal Service and the Director of Retina Research at Ophthalmic Consultants of Boston and one of the principal investigators of the HOME Study. "In contrast to current home monitoring strategies, those with intermediate AMD (bilateral large drusen) or advanced AMD in 1 eye are likely to benefit from home monitoring with the ForeseeHome device to detect the development of CNV at an earlier stage with better preservation of their visual acuity to maximize visual acuity results after intravitreal therapy with anti-VEGF agents."

About the HOME Study

The HOME Study was a controlled, randomized clinical trial that was part of AREDS2. The study was conducted in 44 clinical centers across the U.S., enrolling 1,520 participants at high risk for developing CNV. (With approximately half using the device and the other half acting as controls, using standard care.) The objective of the HOME Study was to determine whether monitoring with the ForeseeHome device plus standard care results in earlier detection of CNV compared to standard care alone. Standard care included instructions to the patient on self-monitoring for CNV. Better visual acuity at the time of CNV detection is both a reflection of earlier CNV detection as well as a favorable predictor for visual function outcomes following the management of CNV with intraocular anti-angiogenic medications.

The results of the study are now online, as published in Ophthalmology.

About the ForeseeHome AMD Monitoring Program

The ForeseeHome AMD Monitoring Program is a prescription-based, comprehensive telemonitoring and data management system that extends the management of AMD to patients' homes between office visits. The test results are transmitted to a central monitoring center that will alert, physicians to immediate, significant visual field changes in their patients, so that patients can be recalled for timely follow-up and necessary treatment may be initiated. The ForeseeHome AMD Monitoring Program utilizes a simple to use device based on preferential hyperacuity perimetry, a form of visual-field testing, to identify minute visual distortions, or metamorphopsia, for the detection of early CNV development.


To read more about Notal Vision and the ForseeHome device, read my full report of March 9, 2010: Notal Vision: The ForeseeHome AMD Monitor and It’s Potential to Save Vision – A First Report.


AMD Update 24: DARPins Phase 2 Trial Results Fall Short

Back in February, I first reported on Allergan’s DARPins in my Update 23: DARPins, The Next “Game Changer” for Wet AMD? In that report, I wrote that Molecular Partners’ MPO112 (Allergan’s AGN-150998) showed promise of improving vision and having a long ocular half-life which appeared to be a vast improvement over both Lucentis and Eylea, perhaps requiring injections every 3-4 months compared to bi-monthly for Eylea and monthly for Lucentis and Avastin. (I also noted a second agreement with Molecular Partners, the licensors of the DARPin technology to Allergan, in which a combination dual action anti-VEGF/PDGF drug therapy was also under investigation.)

Well, the first part of the promise, the longer interval injection rate for the DARPins, has fallen through. As reported by two analyst groups, Allergan presented results last Friday (November 15th) from the Phase 2 trial of AGN-150998 (anti-VEGF DARPin program) in wet AMD at the Retina Subspecialty Meeting ahead of the start AAO annual conference in New Orleans. The results supported the company's decision several months ago, to slow down advancement of the clinical trial, in that the drug failed to meaningful delay the time to retreatment and the associated rates of inflammation were higher than were anticipated. Though Allergan continues to evaluate the drug and still may ultimately advance it into Phase 3 studies, there appears to be only limited competitive threat to Eylea (or, perhaps Fovista, Ophthotech’s combination anti-VEGF/PDGF drug in clinical study – see my two write ups on Fovista, shown below, for more information about this potential drug). Specifically, the analysts see a low likelihood of commercial adoption or integration into the treatment paradigm for wet AMD without any sustained improvement in visual acuity or meaningful delay in the time to retreatment.

In looking at the data presented, the study evaluated two doses of the AGN-150998 (3mg and 4.2mg) vs. Lucentis. The drug was administered at week 4 and then pro re nata (PRN) or by week 16, and then again PRN or by week 32 at the latest. At day 60 and day 90, the 4.2mg dose appeared to delay the need for retreatment in ~10-15% of patients. Looking at the data another way, the 4.2mg dose appeared to delay the median time to retreatment by ~20 days. There were no differences in the percent of patients gaining 15 or more letters in best corrected visual acuity (BCVA) from baseline by week 16, and again at week 32.

In terms of safety, the AGN-150998 treatment was associated with a meaningful rate of ocular inflammation adverse events relative to Lucentis (13% vs. 0%). Specifically, treatment with AGN-150998 had higher rates of uveitis (3% with 3mg, 6% with 4.2mg, 0% with Lucentis), anterior chamber inflammation (2% and 3% vs. 0%), vitritis (7% and 2% vs. 0%).  For reference purposes, historical data imply the rate of intraocular inflammation in AMD trial are 13% and 1% with Lucentis and Eylea, respectively.

Allergan has indicated that it would be making changes to the manufacturing process to hopefully reduce the inflammation seen in the Phase 2 trials, when and if they decide to proceed to a Phase 3 trial.

I was not able to determine if Allergan and Molecular Partners still plan to go ahead with a clinical trial for the dual action drug, which remains in a pre-clinical stage.

References:

Analyst Reports - Private correspondence.

Fovista Reports:

Thursday, October 24, 2013

Gene Therapy in Ophthalmology Update 21: New Gene Therapy Company, Spark Therapeutics, Launches


Children’s Hospital of Philadelphia (CHOP) announced that it had spun off its work in gene therapy to a new, fully integrated company, Spark Therapeutics, that will assume control over two current gene therapy clinical trials: a Phase III study for Leber’s Congenital Amaurosis, an inherited disease that results in blindness caused by mutations of the RPE65 gene, and a Phase I/II study for hemophilia B. The new company is also advancing toward the clinic with gene therapy programs to address neurodegenerative diseases and additional hematologic disorders and other forms of inherited blindness. One such program, in the latter category, already in pre-clinical development at CHOP, could be its study for the treatment of Choroideremia, a rare inherited disorder that causes progressive loss of vision due to degeneration of the choroid and retina.

Editors Note: It should be noted that one clinical trial using gene therapy to treat Choroideremia is already underway at Imperial College London and Oxford University, in conjunction with Moorfields Hospital in London.

The new company has been launched with a $50 million capital commitment from Children’s Hospital to advance and commercialize multiple ongoing programs with clinical proof of concept.

As noted by Susan Young, writing about the launch in Technology Review, “Spark has a chance to be the first gene-therapy company to obtain FDA approval. Results for a late-stage trial of a gene therapy for Leber's Congenital Amaurosis ... are expected by mid-2015. That treatment is one of several gene therapies in or nearing late-stage testing contending to be the first gene therapy approved by the FDA for sale in the U.S.”

The Phase III trial was initiated late last year, and CHOP has made significant progress in enrolling patients. Spark will be sharing additional details on its progress and encouraging results in the very near future.

And, as shown in my table of Ongoing Clinical Trials in Ophthalmology, it is the only gene therapy trial (in ophthalmology) that has advanced to Phase III.

Editors Note: For clarity, is should be noted that there are five other clinical trials underway to treat Leber’s, as shown in my table, but all are currently Phase I or Phase I/II studies. The Spark Therapeutics trial is the farthest advanced.

“The creation of Spark is the culmination of a decade-long commitment by CHOP and our founding team to drive the field of gene therapy forward during a time when many in the industry had moved away,” said Jeffrey D. Marrazzo, co-founder, president and chief executive officer of Spark Therapeutics. “Their vision and long-term dedication have enabled us to effectively address many of the key challenges facing the field and to emerge with one of the industry’s most robust clinical-stage gene therapy pipelines; as well as exclusive rights to commercialize a proprietary manufacturing platform, supply from a world-class manufacturing facility and a founding team with a proven track record of executing safe and effective gene therapy trials for nearly two decades. We are working with great urgency and care to deliver gene therapy products with the potential to transform the lives of those affected by severe genetic diseases.”

Spark builds on the work of CHOP’s Center for Cellular and Molecular Therapeutics (CCMT), established in 2004 as a world-class center for gene therapy translational research and manufacturing. Many of the CCMT’s leaders will assume management roles within Spark or engage with the company as scientific advisors, including Katherine A. High, M.D, a gene therapy pioneer who has served as the director of the CCMT since its inception.

“Gene-based medicines are among the most complex therapeutics ever developed,” said Dr. High. “We at CCMT have persevered through more than a decade of scientific and clinical development and are now closer than ever to realizing the ambitious vision of one-time, potentially curative therapies to address serious genetic conditions. The team at Spark has incredible goals for the treatment of diseases including hemophilia B and inherited blindness, and we look forward to working with them to deliver groundbreaking new treatments to patients in need.”

Spark has entered into agreements with multiple academic institutions to assemble the technology, programs and capabilities needed to deliver its pioneering gene therapy products. Notably, Spark has exclusive rights to commercialize CHOP’s proprietary manufacturing technology and will use clinical-grade gene therapy vectors produced by the CCMT’s state of the art good manufacturing practices (cGMP) clinical facility.

Pioneers in AAV delivery

Over the past two decades, the Spark leadership team has developed unrivaled expertise in the design, manufacturing and delivery of gene therapies using adeno-associated virus (AAV) vectors. AAV has been demonstrated in clinical studies to be a safe and effective vehicle for the delivery of genetic material into targeted cells and provides unique advantages over alternative delivery approaches. The Spark team was among the first to demonstrate human clinical proof of concept in two distinct organ systems — the eye and the liver — establishing a strong foundation for the company’s current programs, and has clinical experience in 15 studies across diverse genetic and non-genetic diseases and five distinct routes of administration.

Spark’s most advanced clinical program is a Phase III study to address blindness caused by mutations in the RPE65 gene. There is currently no pharmacologic treatment for this form of inherited retinal degeneration, which ultimately causes irreversible blindness.

The open-label, randomized, controlled study builds on an earlier clinical study in which 12 patients with RPE65-related blindness demonstrated notable improvement in visual function, moving in some cases from being profoundly blind to being able to recognize faces and ambulate independently. All school-age patients enrolled in the trial were able to transfer from Braille classrooms to sighted classrooms.

One such patient was Corey Haas, whose story is related in the book “The Forever Fix: Gene Therapy and the Boy Who Saved It”.
Corey Haas, his parents, and the CHOP team that treated his Leber’s and gave him back his vision. 
Read Corey’s story in Ricki Lewis’ book, The Forever Fix: Gene Therapy and the Boy Who Saved It.

The team's experience in the clinical study of gene therapy – from designing and manufacturing vectors to conducting studies that have shown strong potential for safety and efficacy – is unparalleled in the field. Clinical-grade vectors prepared by the team have been used to safely treat more than 100 human subjects in 12 clinical trials in the U.S. and EU, across five parenteral routes of administration in genetic and non-genetic diseases. No other group can claim this breadth of expertise and experience in human gene therapy.

The adeno-associated virus (AAV) vectors used in the clinical programs have been demonstrated to be safe and effective vehicles for delivering genetic material into targeted cells, providing unique advantages over alternative therapeutic approaches. The team has established human proof of concept in two organ systems – the eye and the liver – and are advancing a Phase III program in blindness caused by mutations of the RPE65 gene; a Phase I/II program in hemophilia B; and preclinical programs in neurodegenerative diseases and other hematologic disorders and forms of inherited blindness.

Thursday, October 17, 2013

Gene Therapy in Ophthalmology Update 20: Oxford BioMedica Clinical Trials Resume

Back in June, Oxford BioMedica announced that it had voluntarily paused recruitment for its clinical trials for wet AMD  (RetinoStat Phase I), Stargardt’s Disease (StarGen Phase I/IIa) and Usher’s Syndrome (UshStat Phase I/IIa). The company had halted recruitment of the aforementioned studies, as a precautionary measure, while it investigated the detection of very low concentrations of a potential impurity in its clinical trial material derived from a third party raw material.

Oxford has since performed extensive characterization studies using its newly developed, state-of-the-art analytical methods to identify the impurity as highly fragmented DNA derived from fetal bovine serum (FBS), the most widely-used growth supplement for cell culture media.  In light of these findings, Oxford remains convinced of the safety, integrity and quality of its LentiVector platform products and no safety concerns relating to any of the ocular products have been identified in any pre-clinical and clinical data generated to date.

Today, the company announced that following the submission of a comprehensive data package to the FDA and the French regulatory agency, ANSM, it has received agreement from both agencies to resume recruitment into its ocular clinical trials using the existing clinical trial material. The company will continue to use highly sensitive, state-of-the-art analytical methods to ensure the quality and integrity of its lentiviral vector products and will work with FDA and ANSM to define the necessary specifications for future batches of clinical trial material.

Oxford is now working closely with the clinical trial centers to obtain the necessary ethics committee approvals in order to resume recruitment into the clinical studies.

(For a list of the clinical site centers in the U.S. and France involved in the three studies, please take a look at my Gene Therapy Ongoing Clinical Trial Table at http://tinyurl.com/GeneTherapyClncal)

John Dawson, Chief Executive Officer of Oxford BioMedica, said: "We value our relationships with the regulatory authorities and are pleased that, on the basis of our extensive technical investigations to demonstrate the integrity of our products, FDA and ANSM agree with our proposal to resume treating patients in our ocular trials as soon as possible.

"We place the highest importance on safety, and our analytical methods and quality assurance processes are continuously evolving to ensure that we remain at the forefront of gene therapy development and manufacture. I am confident that, with significant opportunities ahead such as the recently-announced AMSCI project win, Oxford BioMedica will continue to lead the way in delivering novel gene therapies to patients."

For your information, Oxford BioMedica has reported that 9 of the 18 patients to be treated in the wet AMD clinical trial had been treated; 12 of the 28 patients in the Stargardt’s trial; and 3 of 18 patients in the Usher Syndrome trial had been treated prior to the halt in recruitment in June.

Coincidently, Genzyme, who is also running a gene therapy clinical trial to treat the wet form of AMD, also announced a halt in recruitment for its trial in July. No reason for the stoppage has been given and all attempts to determine why the halt in recruitment occurred have been rebuffed. As of the last time I had obtained reliable information about the Genzyme trial, 6 of 34 patients to be treated had been treated.


Genzyme Update – October 25, 2013

After many attempts to determine why Genzyme halted its clinical trial recruitment, I have finally received the answer. Here is the statement received from a spokesperson from Genzyme:

“We enrolled 19 patients in this clinical trial, all of whom have been treated. The protocol stated that we would enroll "up to 34" patients, but that number accounted for the possibility of replacing patients who withdrew early from the trial. Since no patients withdrew from the trial, we did not need to recruit 34 patients in order to meet the target enrollment numbers. The protocol specified that we planned to enroll 12 patients in the dose escalation part of the trial, and 10 patients in the second part of the trial, for a total of 22 patients. We stopped enrollment at 19 (three short of this target) purely because our clinical material was coming to the end of its stability protocol. There were no safety or product quality issues. We continue to monitor the 19 patients who were treated in our trial.”

Thank you Genzyme for providing this update.

Tuesday, September 10, 2013

INDEX/SEARCH

INDEX/SEARCH

For your convenience, and because only the last ten posts are shown on the opening page, here is a means for finding all of my posts in an easy-to-use fashion.

Use the Blog Search box in the upper left-hand corner of the header above, enter  "Menu" and click on "enter" and menus for most of my 280 or so postings will come up in an easy to search/find method (including short descriptions and live links.)

Friday, August 16, 2013

Research in Retinal Disease: The Foundation Fighting Blindness Invests $2.1 Million in Seven New Research Efforts

As I continually search the web for interesting news about new technologies for treating retinal diseases, I came across this news from the Foundation Fighting Blindness’ website  yesterday afternoon. It relates to some of the annual grants to researchers that the FFB will be funding this year. It includes better ways of looking at retinal cells (via use of the adaptive optics laser scanning ophthalmoscope) and several projects involving gene therapy, along with a couple looking at ways of, hopefully, stopping the progression of dry AMD.

The following write up is reprinted with permission of the FFB.


August 15, 2013

The Foundation's Scientific Advisory Board (SAB) recently completed its annual grants review process, leading to the allocation of $2.1 million in funding for seven new research projects, including those for identifying new disease-causing gene mutations, developing cross-cutting gene therapies and advancing potential treatments for dry age-related macular degeneration. The three-year grants were awarded after the SAB reviewed 117 proposals submitted to the Foundation last October.

"Grants review is a rigorous, multi-step process that takes most of the year to complete," says Stephen Rose, Ph.D., chief research officer, Foundation Fighting Blindness. "Due to revenue limitations, we can only fund a fraction of the high-quality projects we'd like to fund. That makes the selection process even more challenging. We had to leave several excellent proposals on the table."

Here are brief descriptions of the new research projects:

AOSLO: Detecting Retinal Degeneration Before Vision is Lost

The adaptive optics laser scanning ophthalmoscope (AOSLO) is like a powerful microscope that enables retinal researchers to see structural changes in the retina well before vision is lost from a retinal disease. That power can enable researchers to more quickly determine if a treatment is working in a clinical trial. Austin Roorda, Ph.D., of the University of California, Berkeley, is performing studies of AOSLO to correlate changes in the retina (e.g., loss of photoreceptors) with changes in vision.

Enhancing AOSLO for Expanded Clinical Use

Like Dr. Roorda, Stephen Burns, Ph.D., of the University of Indiana, is working with AOSLO to study the correlation between retinal and vision changes. He is also making AOSLO more affordable by using newer camera technology. In addition, he's employing state-of-the-art computing technologies derived from video games to decrease image-processing times and costs. The new technology will make the imaging process more comfortable for the patient by tolerating more head and eye movement.

Figuring Out Why Severity of Vision Loss Varies for People with XLRP

Researchers have reported for many years that the severity of vision loss for people with X-linked retinitis pigmentosa (XLRP) can vary greatly, even for people within the same family. Stephen Daiger, Ph.D., of the University of Texas Health Science Center at Houston, will be looking at the role of a various biological, genetic and environmental factors in vision-loss variability for those with XLRP. The identification of a significant factor that modulates vision-loss severity - perhaps a protective protein - could lead to a potential treatment.

Finding New Genes Linked to ADRP

Researchers have identified almost two dozen genes linked to autosomal dominant retinitis pigmentosa (adRP), but many are yet to be found. Rui Chen, Ph.D., of Baylor College of Medicine, is on the hunt for those remaining adRP genes. With DNA from 118 adRP families, including 18 families with at least nine affected members, Dr. Chen is well positioned to identify additional genes linked to adRP. Finding the new genes will provide researchers with targets for treatments and cures.

Developing Neuroprotective Gene Therapies to Preserve Vision

John Ash, Ph.D., is developing gene therapies that have the potential to preserve vision in people affected by a broad range of retinal diseases. Unlike corrective gene therapies, which work only for conditions caused by a specific gene, Dr. Ash's proposed treatments are designed to keep the retina healthy independent of the underlying disease-causing gene. He also believes the proteins delivered by his treatments - PIM-1 and STAT3 - will be less likely to cause damaging inflammatory side effects than some previously investigated neuroprotective proteins.

Targeting Inflammation to Halt AMD

Thanks to previous Foundation-funded genetic studies, researchers have strong evidence that the progression of age-related macular degeneration is associated with an over-active immune system. This ultimately leads to inflammation and cell death in the retinal pigment epithelium (RPE), a layer of cells that provides critical waste and nutritional support to photoreceptors. Loss of the RPE subsequently leads to loss of photoreceptors and vision. Jayakrishna Ambati, M.D., of the University of Kentucky, is developing a gene therapy that preserves the RPE by preventing the harmful sequence of immune-system events.

Boosting Cells' Energy Supplies to Save Vision in AMD

Based on prior research, Deborah Ferrington, M.D., of the University of Minnesota, believes that mitochondrial dysfunction in the RPE plays a significant role in the development of AMD. Mitochondria are like miniature organs (organelles) within all cells that provide energy. When not working properly in retinal cells, they can lead to cell death and vision loss. Dr. Ferrington is evaluating compounds that help protect mitochondrial function in the RPE.