Funding opportunities

CF iPS Cells: Generation, Correction, Directed Differentiation, and Engraftment

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06779
Funds requested: 
$1 854 750
Funding Recommendations: 
Not recommended
Grant approved: 
No
Public Abstract: 
This project will develop a cell and gene therapy for cystic fibrosis (CF). CF, the most common inherited disease in the Caucasian population with > 30,000 affected individuals in the US. The efficacy of CF therapies has been limited and does not address the underlying genetic cause or disease associated tissue damage. Mutation corrected, patient-derived CF-induced pluripotent stem (iPS) cells have the potential to repair tissue affected by disease processes with cells/tissue that function normally. The studies test the hypotheses that: 1) CF cells can be converted into iPS cells by Sendai virus reprogramming and maintain long-term DNA integrity, 2) CF mutations can be corrected in iPS cells by small DNA fragments (SDFs) in conjunction with sequence specific transcription activator-like effector nucleases (TALENs) or helper-dependent adenovirus (HDAV) vectors and maintain DNA integrity, and 3) corrected iPS cells can differentiate into chromosomally stable airway epithelial and inflammatory cell progenitors that can engraft and repair disease damaged tissues. The proposal will: (yr 1) reprogram CF patient iPS cells with a Sendai virus vector containing Oct4, Sox2, Klf4, and/or L-Myc transgenes, (yrs 1-2) repair the disease causing mutation by gene editing using SDFs with TALENs or by HDAV) homologous recombination, and (yrs 2-3) direct the differentiation of corrected cells into human lung airway epithelium and inflammatory cell progenitors associated with CF pathology.
Statement of Benefit to California: 
There are > 2500 individuals with CF in California and of the ~ 500,000 new births in California every year, >100 babies are born with CF. Patients with CF require lifelong care that involves expensive therapies to treat the manifestations that result from opportunistic infections and multi-organ dysfunction. While there has been progress in the treatment of CF and the mean survival of someone with CF has increased to 38 yrs, there is no cure for CF, the underlying pathology, and the extensive organ and tissue damage. The only effective, albeit short-term, amelioration of the airway disease pathology has been allogenic lung transplantation. Aside from the human cost and suffering caused by CF, the economic impact to California is substantial. The cost of treating someone with CF is between $10,000 to $25,000/yr/patient, with an estimated lifetime cost of $300,000 to $450.000 per patient. One approach to prevent the disease has been through early detection and prenatal diagnosis, where the usual outcome is selective abortion of the affected fetus. This project offers an alternative approach for possibility curing both newborn and adult patients with their own cells that have been reprogrammed, corrected and converted to cells that will regenerate tissues affected by CF pathology. The benefit to California would be to eliminate emotional and physical suffering in patients and mitigate the economic impact that the life-long treatment has on the medical system.
Review Summary: 
This is a development candidate feasibility award (DCF) proposal with the aim to treat cystic fibrosis (CF), a genetic disorder that affects the lungs and digestive system, presents with inflammatory dysfunction, and severely reduces quality of life and life span. The applicant proposes to generate autologous induced pluripotent stem cells (iPSCs) from CF patients; to correct the mutant gene and then to differentiate the corrected cells into airway epithelial cells and blood-forming (hematopoietic) cells, the proposed development candidates intended for transplantation. Finally, the applicant plans to assess the functionality of the corrected iPSC-derived airway cells upon engraftment in various ex vivo human lung and trachea preparations and the ability of the corrected iPSC-derived hematopoietic cells to produce inflammatory cells with normal function. Objective and Milestones - The objective of this proposal is not sufficiently focused and is overly ambitious given the project timeframe. - The target product profile (TPP) is not scientifically reasonable, since two products, airway cells and hematopoietic cells, each with very different characteristics and development pathways, are proposed. Furthermore, the TPP does not adequately define the characteristics of each of the target products. - The milestones address a number of key activities to achieve preclinical proof of concept but should have been narrowed to single approaches. Success criteria lacked quantitative specifications. - The generation of gene corrected, lineage differentiated, functionally competent, engraftable cells that will repopulate airways and bone marrow presents several challenges that cannot be solved within the timeframe of this proposal. Rationale and Significance - The proposal fails to address how to overcome current obstacles to repopulating airway epithelium with functional cells or to achieving engraftment of iPSC-derived hematopoietic stem cells at therapeutic levels. The proposal as described is therefore highly unlikely to lead to proof of concept of efficacy of the development candidates. - CF is an extremely serious disease. If successful, this proposal would have a significant impact in the field and for CF therapy, as it would overcome the problem posed by rejection of allogeneic cells and various issues related to the use of vector-based gene therapy. Feasibility and Design - A significant weakness in the preliminary data is the lack of any in vivo data supporting engraftability of iPSC-derived cells. Although the applicant presents some early stage, encouraging co-culture data, this did not convince reviewers that repopulation of an airway is readily achievable. - There are many different cell populations present in the lung and the proposal fails to mention a strategy to allow induced differentiation into appropriate lineages and spatial relationships in decellularized lungs. While populating a trachea in a bioreactor is feasible, repopulation of an entire decellularized lung is a leap well beyond current feasibility and is unlikely to be accomplished within the funding period of this RFA. - Reviewers noted that repopulating the marrow with corrected hematopoietic cells is not the most pressing need in CF, and suggested that the applicant solve repopulation of the airways with corrected cells before proceeding to the marrow. Qualification of the PI (Co-PI, Partner PI) and Research Team - The PI has an outstanding track record in clinical and laboratory investigation in relevant fields and has a history of productive leadership of research teams. However, there is a lack of appropriate track record related to in vivo engraftment of progenitor cells, or tissue engineering. - The team as a whole lacks experience related to decellularized scaffolds. - There was a concern regarding the lack of product development expertise in the team. A biotech product development collaborator would add great value to the current team. - Reviewers deemed the applicant’s commitment level and the budget to be appropriate. Collaborations, Assets, Resources and Environment - The collaborations appear to be appropriate. - Appropriate institutional support and an excellent environment exist for the proposed work. Responsiveness to the RFA - A successful execution of the proposed studies would be responsive to the objectives of the RFA, as this would achieve proof of concept for stem cell-based development candidates.
Conflicts: 

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