Stem Cells in Ophthalmology Update 27 ACT Interim Clinical Results Are Outstanding

Having treated 36 patients in two clinical trials for Stargardt’s Macular Dystrophy (SMD - 24 patients to date) and for dry Age-Related Macular Degeneration (AMD - 12 patients to date), Advanced Cell Technology reported the interim results obtained with 18 of these patients (9 in each trial) in the US-based studies. Both trials (NCT01345006 - Stargardt’s, and NCT01344993 - AMD) began in July 2011, giving the company up to three-year’s data for the earliest patients, and a median of 22 months followup for all. The interim results were reported in The Lancet, published online October 14, 2014 in: “Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt’s macular dystrophy: follow-up of two open-label phase 1/2 studies”.

An additional Stargardt’s trial, being conducted at two clinics in the United Kingdom, with 12 patients enrolled (NCT01469832), along with 3 of the 4 patients treated in each of two trials with better vision candidates, as part of the two clinical trials in the publication (Phase IIa), were not included in The Lancet results.

As noted by Paul K. Wotton, Ph.D., President and Chief Executive Officer of Advanced Cell Technology, "These study results represent an important milestone and strengthen our leadership position in regenerative ophthalmology. We would like to thank the patients for their willingness to participate in these studies. Our findings underscore the potential to repair or replace tissues damaged from diseases. We plan to initiate comprehensive Phase 2 clinical trials for the treatment of both AMD and SMD, two disease states where there is currently no effective treatment."

Editors Note: As announced on October 15th by the company, the Phase II dry AMD clinical trial (50 Patients) will start during the 1st Half of 2015 and is expected to be completed in the middle of 2016, taking place at 10 Trial Sites across North America. The Phase II SMD clinical trial (100 patients) will start during the 4th Quarter of this year or by the end of the year. It will take 18-24 months to complete, taking place at 30 sites across North America and Europe.

Robert Lanza, M.D., Chief Scientific Officer of ACT and co-senior author of the paper, commented, "Diseases affecting the eye are attractive first-in-man applications for this type of investigational therapy due to the immune-privileged nature of the eye. Despite the degenerative nature of these diseases, the vision of 10 of 18 patients showed measurable improvement at the six month follow up, after transplantation of the RPE cells. Furthermore, the cells have been well tolerated for a median period of 22 months with two of the patients treated more than three years ago. We are pleased that there have been no serious safety issues attributable to the cells observed in any of the patients."

Steven Schwartz, M.D., Ahmanson Professor of Ophthalmology at the David Geffen School of Medicine at UCLA and retina division chief at UCLA's Jules Stein Eye Institute, principal investigator and co-lead author of the publication said, "The data published in The Lancet support the potential safety and biological activity of stem cell-derived retinal tissue. Once again, surgical access to the subretinal space has proven safe. However, for the first time in humans, terminally differentiated stem cell progeny seem to survive, and do so without safety signals. Combined with the functional signals observed, these data suggest that this regenerative strategy should move forward. This is a hopeful and exciting time for ophthalmology and regenerative medicine."

These two studies provide the first evidence of the mid- to long-term safety, survival, and potential biologic activity of pluripotent stem cell progeny into humans with any disease. In addition to showing no adverse safety issues related to the transplanted tissue, anatomic evidence confirmed successful engraftment of the RPE cells, which included increased pigmentation at the level of the RPE layer after transplantation in 13 of 18 patients.

There was no evidence of adverse proliferation, rejection, or serious ocular or systemic safety issues related to the transplanted tissue. Adverse events were associated with vitreoretinal surgery and immunosuppression. Thirteen (72%) of 18 patients had patches of increasing subretinal pigmentation consistent with transplanted retinal pigment epithelium. Best-corrected visual acuity, monitored as part of the safety protocol, improved in ten eyes, improved or remained the same in seven eyes, and decreased by more than ten letters in one eye, whereas the untreated fellow eyes did not show similar improvements in visual acuity. Vision-related quality-of-life measures increased for general and peripheral vision, and near and distance activities, improving by 16–25 points 3–12 months after transplantation in patients with atrophic age-related macular degeneration and 8–20 points in patients with Stargardt’s macular dystrophy.

Figure 3: Change from baseline in best-corrected visual acuity in patients with age-related macular degeneration (A) and Stargardt’s macular dystrophy (B) Median change in best-corrected visual acuity was expressed as number of letters read on the Early Treatment of Diabetic Retinopathy Study visual acuity chart in patients with age-related macular degeneration (A) and Stargardt’s macular dystrophy (B). Red lines show treated eyes and blue lines show untreated eyes of patients during the first year after transplantation of the cells derived from human embryonic stem cells. Green lines show the difference between the treated and untreated eyes. Patients who underwent cataract surgery after transplantation are not included in the graph. There was a significant difference in the letters read in transplanted eyes of patients with age-related macular degeneration versus non-transplanted controls at 12 months (median 14 letters vs –1 letter; p=0·0117). There was an increase in letters read in transplanted eyes of patients with Stargardt’s macular dystrophy versus non-transplanted controls at 12 months (median 12 letters vs two letters, although the sample size was too small to allow reliable calculation of the Wilcoxon signed-rank test).

The SMD and dry AMD trials are prospective, open-label studies designed to evaluate the safety and tolerability of human embryonic stem cell (hESC)-derived RPE cells following sub-retinal transplantation into patients at 12 months, the studies' primary endpoint. Three dose cohorts were treated for each condition in an ascending dosage format (50,000 cells, 100,000 cells, and 150,000 cells). Both the SMD and dry AMD patients had subretinal transplantation of fully-differentiated RPE cells derived from hESCs.

Dr. Anthony Atala, a surgeon and director of the Wake Forest Institute for Regenerative Medicine at Wake Forest University in an accompanying commentary in The Lancet said:

"It really does show for the very first time that patients can, in fact, benefit from the therapy.

That allows you to say, 'OK, now that these cells have been used for patients who have blindness, maybe we can also use these cells for many other conditions as well, including heart disease, lung disease and other medical conditions.' "

Human embryonic stem cells have the ability to become any kind of cell in the body. So scientists have been hoping the cells could be used to treat many diseases, including Alzheimer's, diabetes and paralysis. But the study is the first human embryonic stem cell trial approved by the Food and Drug Administration that has produced any results.

"It is really a very important paper."

The co-authors of the study summarized their interpretation of their results in this way:

“The results of this study provide the first evidence of the medium-term to long-term safety, graft survival, and possible biological activity of pluripotent stem cell progeny in individuals with any disease. Our results suggest that human-embryonic-stem-cell-derived cells could provide a potentially safe new source of cells for the treatment of various unmet medical disorders requiring tissue repair or replacement.”

My takeaway from reading The Lancet article (and several of the accompanying writeups about the study) is, the use of RPE derived from embryonic stem cells is safe and efficacious, particularly in the eye. But most of all, this important study shows that Advanced Cell Technology is able to safely stop the progression of to-date untreatable dry AMD and SMD retinal diseases (17 of 18 patients) and to improve the vision in those who have lost considerable sight (10 of 18 patients).

Finally, the two clinical trials that are reported on in The Lancet, were done on patients with nothing to lose (with vision no better than 20/400), whereas patients in the Phase IIa study, still in progress, have vision no worse than 20/100. It is anticipated that even better results will be shown with this better vision group.

References:

1. ACT Announces Positive Results from Two Clinical Trials Published in The Lancet Using Differentiated Stem Cell-Derived Retinal Pigment Epithelium (RPE) Cells for the Treatment of Macular Degeneration, ACT Press Release, October 14, 2014

2. Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt’s macular dystrophy: follow-up of two open-label phase 1/2 studies, Schwartz, SD, Lanza R, et al, The Lancet, Online, October 14, 2014.

Other Resources:

Encouraging New Paper on ACT Stem Cell-Based Trial for Macular Degeneration, Paul Knoepfler, Knoepfler Lab Stem Cell Blog, October 14, 2014

Embryonic Stem Cells Restore Vision In Preliminary Human Test, Rob Stein, NPR Health Blog, October 14, 2014

Disclosure: As of September 17, 2014, I own a small number of shares of the company’s stock.

Gene Therapy in Ophthalmology Update 17 Hemera Biosciences Obtains Initial Funding

In December 2011, following that year’s AAO Meeting, I wrote about Hemera Biosciences and its complement regulation therapy via the use of gene therapy to prevent membrane attack complex (MAC), the final stage of the complement cascade that is implicated in both dry and wet AMD. (Gene Therapy in Ophthalmology Update 5: A Complement-Based Gene Therapy for AMD)

I am now happy to report that Hemera has obtained initial funding, along with the issuance of a US Patent and can now begin manufacturing its drug, soluble CD59 (protectin), perform animal toxicology and initiate a phase 1 clinical study.

To review, HMR59 is a gene therapy using an AAV2 vector to express a soluble form of a naturally occurring membrane bound protein called CD59 (sCD59), which blocks MAC. Membrane attack complex is the final common pathway of activation of the complement cascade, and is composed of complement factors C5b, C6, C7, C8 and C9 that assemble as a pore on cell membranes. The MAC pore induces ionic fluid shifts leading to cell destruction and ultimate death. 

HMR59 works by increasing the production of sCD59 by ocular cells. The sCD59 released from the cells will circulate throughout the eye and penetrate the retina to block MAC deposition and prevent cellular destruction. By blocking MAC, the remainder of the upstream complement cascade is left intact to perform its normal homeostatic roles.

The primary focus for the company will be preventing the conversion of the dry form of AMD from progressing into the wet form, however, they think that there's a role for HMR59 in treating the dry form (drusen and GA) as well as wet (neovascular) AMD.

Here is the company’s news release:

Hemera Biosciences Raises $3.75 Million; Patent Issued for TreatingAge-related Macular Degeneration

BOSTON, MA (March 15, 2013)  Hemera Biosciences announced its Series A financing of $3.75 million and issuance of US Patent 8,324,182 B2 on December 4, 2012, for treating age-related macular degeneration (AMD) with a human protein, soluble CD59 -- otherwise known as protectin.

“Human genetic studies and preclinical research have shown that alterations in complement – a significant driver of inflammation -- play a key role in the development of both wet and dry AMD,” said Adam Rogers, MD, one of the founders of Hemera. 

Preclinical studies done in the laboratory of Rajendra Kumar-Singh, PhD, another Hemera founder, have shown that intravitreal injection of an adeno-associated virus  that expresses soluble CD59, in an animal model, prevents the development of choroidal neovascularization. Choroidal neovascularization is the leading cause of  severe vision loss due to the wet form of AMD.

“Membrane attack complex (MAC) formation is the last step in the complement inflammation pathway.  Soluble CD59 when expressed in our animal models using gene therapy, prevents the development of MAC, death of retinal pigment epithelial cells and prevents abnormal blood vessel development in the eye.  Use of gene therapy to express soluble CD59 allows for long term treatment for this chronic blinding disease,” said Dr. Kumar Singh.

With the $3.75 million of financing raised in this initial round of funding, Hemera expects to have sufficient resources to manufacture the drug, perform animal toxicology studies and initiate a phase 1 study.

The founders and management team include Elias Reichel, MD, Jay Duker, MD, Rajendra Kumar-Singh PhD , and Adam Rogers, MD who all are on faculty at Tufts University School of Medicine.

About Hemera

Hemera Biosciences, founded in 2010, is a private company headquartered in Boston, Massachusetts that focuses on developing and commercializing gene therapy for age-related macular degeneration and other ocular conditions.

Hemera is developing its proprietary soluble CD59 gene therapy technology as a treatment for age-related macular degeneration for both the dry and wet forms of the disease.  The company’s lead program is the first and only complement therapy that directly targets MAC.  Hemera was started by some of the world’s leading experts in AMD and gene therapy.

Stem Cells in Ophthalmology Update 14 Current Stem Cell Clinical Trials

Thanks to new friend, Alexey Bersenev, and his stem cell blog, Hematopoiesis, I have been able to add several companies and medical institutions to my list of those involved in ophthalmic clinical trials using stem cells. Alexey recently posted a blog entry, Cell therapy clinical trials in 2011, describing his efforts to put together a list of entities undertaking stem cell clinical trials. He came up with a total of 151 clinical trials underway, of which eight were in ophthalmology.

I am able to add one that he missed, giving a total of nine clinical trials underway (and another about to start). The new list, showing the trials by ophthalmic application, are presented in the accompanying table.

Anyone wishing a pdf file of the table can get it by sending me an email request.