ProKidney Corp. announced statistically significant and clinically meaningful results from its Phase 2 REGEN-007 trial evaluating rilparencel, an autologous cellular therapy, in patients with chronic kidney disease (CKD) and diabetes. The topline data demonstrated substantial improvements in kidney function preservation, supporting the therapy's potential as a breakthrough treatment for advanced CKD.
Primary Efficacy Results
In Group 1 of the trial (n=24), patients who received two scheduled rilparencel injections—one in each kidney approximately three months apart—showed remarkable kidney function stabilization. The annual decline in estimated glomerular filtration rate (eGFR) slope improved by 78%, from -5.8 mL/min/1.73m² in the pre-injection period to -1.3 mL/min/1.73m² following the last injection. This 4.6 mL/min/1.73m² per year difference was both statistically significant (p<0.001) and clinically meaningful.
Group 2 (n=25) tested an exploratory dosing regimen where patients received a single injection followed by a second injection only if kidney function worsened based on specific triggers. These patients showed a 50% improvement in eGFR slope decline, from -3.4 mL/min/1.73m² to -1.7 mL/min/1.73m², representing a 1.7 mL/min/1.73m² per year improvement. While not statistically significant (p=0.085), this result suggests evidence of a dose response.
Study Design and Patient Population
REGEN-007 is a multicenter, Phase 2, open-label, randomized two-arm trial enrolling patients with diabetes, CKD, and an eGFR of 20-50 mL/min/1.73m². Of the 53 patients randomized, 49 received at least one rilparencel injection and comprised the modified intent-to-treat population.
The patient demographics showed a majority were male (69%) with a mean age of 60 years. Thirty-eight patients (78%) had type 2 diabetes mellitus, while 11 (22%) had type 1 diabetes. Most patients (80%) were receiving standard-of-care treatments including ACE inhibitors or ARBs, and 37% were on SGLT2 inhibitors. The baseline mean eGFR was 33±10 mL/min/1.73m², with notably higher median urine albumin-to-creatinine ratio in Group 1 (792 mg/g) compared to Group 2 (229 mg/g).
Safety Profile
No rilparencel-related serious adverse events were observed across all 49 patients who received at least one injection. The safety profile remained consistent with previously reported study results and was comparable to a kidney biopsy procedure, supporting the therapy's favorable risk-benefit profile.
Regulatory Pathway and Phase 3 Implications
The results strengthen ProKidney's confidence in its ongoing Phase 3 PROACT 1 study design, given the similarity between the dosing regimen in REGEN-007 Group 1 and the Phase 3 protocol. Notably, 15 of the 24 patients in Group 1 (63%) met key Phase 3 PROACT 1 inclusion criteria, with similar efficacy results observed in this subgroup.
"We are very encouraged by the REGEN-007 topline results that demonstrated a robust improvement in eGFR slope following treatment with rilparencel in Group 1 as well as evidence of a dose response in Group 2," said Bruce Culleton, M.D., CEO of ProKidney. "These data bolster our confidence in the design of our ongoing Phase 3 PROACT 1 study."
The FDA previously confirmed during a Q4 2024 Type B meeting that the accelerated approval pathway is available for rilparencel if an acceptable surrogate endpoint, such as eGFR slope, is used. ProKidney has scheduled an upcoming FDA Type B meeting this summer to confirm the approach to using eGFR slope as the surrogate endpoint for accelerated approval.
Clinical Context and Unmet Need
Chronic kidney disease affects an estimated 37 million adults in the U.S., with diabetes being the leading cause. ProKidney is developing rilparencel for patients with Stage 3b/4 CKD and diabetes, representing a population of 1 to 2 million people in the U.S. While current treatment options aim to slow disease progression, there remains substantial unmet need for therapies that can stabilize kidney function and delay or prevent the need for dialysis in patients with advanced CKD.
Rilparencel, which has received Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA, represents a first-in-class autologous cellular therapy approach to treating CKD. The full REGEN-007 results will be submitted to the American Society of Nephrology's 2025 Kidney Week as a late-breaking clinical trial presentation.
