To develop Stem cell derived corneal tissue as a substitute for donor-sourced cornea normally used for transplantation of partial thickness grafts
Disease Team Planning
The goal of this proposal is to create and prepare a team of California-based researchers and clinicians to write a Disease Team Research Award application aimed at curing corneal vision loss through the culture and implantation of stem-cell-derived full or partial thickness human corneal grafts. Corneal vision loss is a growing malady that affects millions of persons worldwide. The efficiency of regulatory approval and the significant benefit to a very large patient population worldwide will validate and promote California’s efforts to become the world leader in stem-cell-based regenerative medicine. The research concept is to optimize existing technologies to differentiate human stem cells into sterile, standardized, functional, FDA-approved human corneas and corneal tissue under cGMP conditions. Manufacturing methods will be created to produce standardized corneal tissue that will be quality tested and shipped to corneal transplant surgeons for implantation using existing techniques. A disease team research approach is well suited to conduct the basic and transitional research necessary to bring this therapeutic concept to the clinic. The goal of this proposal requires knowledge and experience in a broad set of scientific and clinical disciplines, including the fields of histology, corneal structure and function, molecular and genetic biology, immunology, corneal transplantation, cGMP manufacturing and clinical trial design and implementation. The planning award will allow the assembly of such a team. Corneal vision loss as a disease target is very well suited as the focus for a Disease Team Award. The corneal constructs have been created and proof of principle is established. Regulatory approval of the implantation of stem-cell derived corneal tissue should be minimal. Clinical trial design is facilitated by the fact that subjective analysis of improved vision is available from patients as well as objective analytical data from clinicians. Intellectual property is likely to be generated through this work, resulting in increased valuation for California research organizations involved. This will generate further growth and investment and result in increased employment for Californians and increased tax revenues for California. Planning will use a strategic planning process. This process will consist of a set of direct meetings with internal and external experts to formulate objectives aimed at finding gaps in human and material resources. These gaps will be filled and follow-on meetings will take place to find and fill remaining weaknesses in the team. Once a team is formed, objectives will be formed. Management tactics will consist of implementation plans containing measurable goals, assignment of responsibilities and timelines, and periodic meetings to evaluate the success or failure the objectives.
Statement of Benefit to California:
Large economic and health benefits will accrue to California and critical validation of stem-cell-based regenerative medicine can be established through the creation and implantation of human corneas and corneal tissue derived from human stem cells. A growing billion dollar market for corneal tissue currently exists. The rationale and justification of funding stem-cell-based regenerative medicine can be expediently established since proof of principle is established and the regulatory pathway is less demanding. According to the Eye Bank Association of America’s 2006 Eye Banking Statistical Report, there are more than 34,000 corneal transplants performed annually in the US. An additional 150,000 transplants are performed in the rest of the world. There are eight million corneal blind patients in developing countries (Sinha et al., 2005) who would benefit from corneal replacement were it not for the lack of established eye banking operations and religious/ethical issues. Concern over donor-to-recipient disease transmission and the increasing use of LASIK treatment has reduced the availability of donated corneas and increased costs. Demand for corneal tissue is growing based on advances in corneal transplant techniques (Goins et al., 2007). Even considering the fact that fees would be less in developing countries, the existing corneal transplant market is billions of dollars in size and is growing. Intellectual property is likely to be generated through this work, resulting in increased valuation for California research organizations involved. This will generate further growth and investment and result in increased employment for Californians and increased tax revenues for California. Regulatory approval of the implantation of stem-cell derived corneal tissue should be minimal in comparison to other stem cell based therapies. The front of the eye is an immune privileged site (Cursiefen et al., 2007). Regulatory approval for corneal transplantation techniques already exists. Clinical trial design is facilitated since subjective analysis of improved vision is available from patients as well as objective analytical data from clinicians. Stem cells can be used to generate sufficient corneal tissue to meet the worldwide demand to treat corneal blind patients and provide significant income and employment to California. The tissue source will not be subject to donor-related medical issues or to ethical or religious resistance associated with donor tissue transplantation. The efficiency of regulatory approval and the significant benefit to a very large patient population worldwide will validate and promote California’s efforts to become the world leader in stem-cell-based regenerative medicine.
Executive Summary This application proposes the creation of a Disease Team whose goal is to cure corneal vision loss through the culture and implantation of stem-cell-derived full or partial thickness human corneal grafts. Currently corneal grafts are obtained from deceased donors, which can impose risk of disease transmission. Although systemic immunosuppression is not required, the topical immunosuppression regimens do not protect fully against rejection. The corneal tissue will be developed from human embryonic stem cells or parthenogenetic stem cells for which the applicants intend to optimize existing technology to produce them under GMP conditions. Reviewers noted the importance of generating specific cell types that are suitable for transplantation in humans for diseases such as those that affect the eye. However, this proposal was found to have many weaknesses including that it was poorly written and offered poor rationale for the use of parthenogenetic stem cells. Although HLA homozygous cells can be produced through this method, reviewers felt its importance was overstated as the plan does not take into account the extensive HLA polymorphisms in the populace and the low likelihood of having a complete pool of human HLA homozygous parthenogenetic stem cells available. Although this field is mature enough to consider therapeutic stem cell transplantation, the proposed project was found not convincing and unrealistic for translation to the clinic within 5 years. The principal investigator (PI) was noted to have extensive experience in translational work with in vitro fertilization and parthenogenetic stem cell development, but reviewers found the productivity of the PI difficult to judge as many publications were in unfamiliar journals. The PI appears to have limited experience in disease team planning and with regulatory processes in the United States. However, the PI has identified some collaborators who will bring needed expertise Overall, the proposed approach was viewed as vague, not sufficiently justified, and not coordinated into a coherent plan. Reviewer Synopsis This proposal aims to generate corneal tissue from human embryonic stem cells (hESCs). The overall goal of this application is to ultimately provide a cure for corneal vision loss from hESCs. The PI proposes to prepare a team of researchers and clinicians toward writing a research award application, starting by optimizing existing technology for differentiation of parthenogenetic human stem cells (phSCs). These cells must differentiate into different corneal structure produced under GMP procedures. This requires knowledge and experience in a broad set of scientific and clinical disciplines, including the fields of histology, corneal structure and function, molecular and genetic biology, immunology, corneal transplantation and clinical trial design and implementation. Reviewer One Comments Concept: The formation of any specific cell types suitable to transplantation in humans represents a highly significant endeavor and is of the highest priority for this type of application. There are however several major shortcomings, for example using parthenogenic stem cells which are derived from abnormal embryos. Many other shortcomings highlight the poor quality of the proposal. It is very poorly written and very difficult to follow. Thus, despite strong significance, the quality of the proposed science is too poor to justify support at this stage Five consultants include Dr. Hans Keirstead (UCI, stem cell researcher), Dr. Steinert (ophthalmologist from an unspecified institution), Dr. Chen (North County Laser Eye Assoc., San Diego), Mr. Requard, (VISION SHARE, Apex, NC, Managing Director), and Mr. Janus, (President of International Stem Cell Corp.) Each will receive $5,000 for their advice. There seem to be nine specific aims. Principal Investigator: While I have little doubt about the qualifications of the PI and the eventual final team, I do not recognize any of the forums in which the author has published manuscripts. Examples include four references to the Russian Journal of Genetics. Certainly the caliber of these forums are not on par with the overly-ambitious aspect of the proposed work. Planning Approach: The planning approach remains vague, unjustified, and uncoordinated. Reviewer Two Comments Concept: The application is of high significance as it deals with an approach to curing corneal vision loss through culture and implantation of stem cell-derived human corneal grafts. More than 34,000 corneal transplants are performed annually in the U.S. and concerns about donor to recipient disease transmission and the increasing use of Lasik treatment have reduced donor availability and increased cost. Meanwhile, demand for corneal tissue is growing based on advances in corneal transplant techniques. The investigators aim to optimize existing technologies to differentiate human parthenogenetic stem cells or embryonic stem cells into sterile, standardized, functional, FDA-approved human corneas and corneal tissue under GMP conditions. Constructs “comparable with cornea” tissue have been created, proving the concept that these can generate a non-keratinized stratified epithelium on a basal lamina that has characteristics of Bowman’s layer and has a fibrous layer underneath. Presented data suggest the existence of a cornea-like tissue structure, although the presence of an endothelial layer is not clearly demonstrated. The investigators propose to use human HLA homozygous parthenogenetic stem cells with common haplotypes to allow HLA matching to patients to reduce post-operative rejection. However, this plan does not take into account the extensive HLA polymorphism in the populace and the impossibility of having a complete pool of human HLA homozygous parthenogenetic stem cells with all possible haplotypes available. Another application from the investigator’s company proposes to generate these lines, but the most abundant HLA haplotypes they identify are found in only a few percent of people, and these haplotypes do not include HLA-DP, which is not in strong linkage disequilibrium with the loci that are included in these analyses. Thus, it seems likely that HLA-related rejection issues would affect this approach to allogeneic corneal transplantation. Moreover, the investigators seem to disregard the possibility that minor histocompatibility antigens could be a problem. If the lack of a role for the hundreds of human minor histocompatibility antigens has been established, which is possible, given the immune privilege of the anterior chamber, the investigators should cite evidence that HLA-identical corneas are not at risk of rejection. In summary, the idea is relatively mature, but the feasibility is somewhat questionable. Principal Investigator: Nikolay Turovets, Ph.D., is a senior Research Scientist at International Stem Cell Corporation. He has extensive experience in translational work with in vitro fertilization and parthenogenetic stem cell development in Russia. He has established a collaboration with Roger Steinert, MD, Vice Chair of Clinical Ophthalmology at UC Irvine. He also lists Dr. Hans Keirstead as a consultant, as well as Dr. Paul Chen and Jake Requard at Vision Share, as well as Jeffrey Janus, President of International Stem Cell Corporation. In summary, the Principal Investigator has limited experience in disease team planning and with regulatory processes in the United States. However, he has identified some collaborators who will bring needed expertise. Planning Approach: The planning is described in somewhat general terms, without detailed description of the outside expertise that will be needed.