jCell is a first-in-class investigational treatment for RP which has received FDA Regenerative Medicine Advanced Therapy (RMAT) designation. In addition to RMAT, jCell has received Orphan Drug designation from the FDA and the European Medicines Agency (EMA).
The phase 2b trial was a multicenter, randomized study that evaluated the safety and efficacy of intravitreal injection of jCell therapy in adult subjects with RP. A large and broad set of patients with RP with best-corrected visual acuity (BCVA) between 20/80 and 20/800 were randomized to treatment versus sham. Treatment consisted of a single intravitreal injection of either 3 or 6 million human retinal progenitor cells (hRPC). The study evaluated changes in visual function and functional vision in subjects with RP who received a single jCell injection in comparison to a sham-treated control group.
The primary endpoint in the phase 2b study was mean change in best corrected visual acuity (BCVA) from baseline to month 12. Secondary endpoints included low light mobility, contrast sensitivity, kinetic visual fields, and a visual function questionnaire. In a post hoc exploratory analysis, the primary and secondary endpoints were assessed in a target subgroup of patients meeting the following criteria: 1) study eye with reliable fixation (≥12° central diameter and/or steady central fixation) and 2) study eye did not have significantly worse BCVA than the fellow eye (≤15 letters).
The phase 2b clinical trial was specifically designed to learn more about the clinical effects of jCell therapy in a broad set of patients suffering from RP to better understand three critical study variables: the optimal jCell dose, the performance of clinical trial endpoints in the study population and the RP patient population likely to realize the most pronounced improvement from a single jCell treatment during the 12-month pivotal trial study period.
Phase 2b Results
A total of 84 patients were randomized of which 74 met criteria for the per protocol analysis. The mean change in BCVA from baseline to month 12 were +2.81, +2.96, and +7.43 letters in the sham (N=26), 3.0×106 hRPC (N=25), and 6.0×106 hRPC (N=23) treatment arms, respectively. In a post hoc exploratory analysis of the target subgroup (n=37), mean change in BCVA from baseline to month 12 were +1.85, -0.15, and +16.27 letters in the sham (N=13), 3.0×106 hRPC (N=13), and 6.0×106 hRPC (N=11) treatment arms, respectively (p=0.003 for 6.0×106 hRPC vs sham). Supportive improvements in the 6.0×106 hRPC target subgroup compared to the control (sham) group were also observed in all secondary endpoints which further support the BCVA findings in this subpopulation. Adverse events were generally minor and transient; there was one serious adverse event in the 3.0×106 hRPC arm of Grade 3 ocular hypertension that resolved with treatment, but no serious adverse events nor any adverse events greater than Grade 1 (mild) in the higher, 6 million cell treatment group during the 12-month study period that were related to the study treatment.
Based on these results, the company plans to advance jCell into a pivotal trial utilizing the data generated, which is supportive of both the efficacy and safety of jCell therapy in a broad set of RP patients. The phase 2b study also provides essential insights into the three critical study variables which are key to optimizing the probability of technical success of the upcoming jCell pivotal trial.
“There is currently no effective treatment for RP, and once photoreceptors are lost, they do not regenerate. The promising results from this phase 2b study suggest that jCell therapy in patients with RP can result in significant slowing of visual deterioration and an improvement in function of existing photoreceptors. The primary goal of jCell therapy is to preserve, and potentially improve vision by intervening in the disease process at a time when dystrophic photoreceptors can be protected and reactivated. We are excited to be continuing the development of jCell investigational therapy, based on these promising phase 2b results, for patients with this degenerative retinal disease,” Anthony Joseph, MD, Ophthalmic Consultants of Boston, who presented the phase 2b data at the ASRS meeting, said in a company news release.
“We are thrilled to report these encouraging phase 2b results from one of the largest studies ever conducted in RP, which indicate significant clinical activity of jCell in patients agnostic of genetic subtype,” said Paul Bresge, Chief Executive Officer, jCyte, Inc. “The phase 2b results reported that jCell therapy had promising efficacy and was well tolerated in patients, and we plan to advance jCell into a pivotal clinical trial in 2021. There is currently no FDA approved treatment option for RP patients, irrespective of genetic subtype. We believe jCell has the potential to be the first approved therapy to address this critical unmet medical need, and dramatically improve the lives of patients with this progressive, blinding disease which typically presents early in the lives of the approximately 1:3500 people who are affected.”