Rilparencel Improves eGFR Slope in Phase 2 CKD, Diabetes REGEN-007 Trial

ProKidney Corp has announced statistically significant and clinically meaningful positive topline results from the full Group 1 modified intent-to-treat (mITT) population of the phase 2 REGEN-007 trial evaluating rilparencel in patients with chronic kidney disease (CKD) and diabetes.1

Announced on July 8, 2025, the topline data showed annual estimated glomerular filtration rate (eGFR) slope decline improvement in patients who received 2 scheduled rilparencel injections, 1 in each kidney, approximately 3 months apart. Of note, evidence of a dose response was also observed in a second group of patients who received a single rilparencel injection followed by a second injection only if kidney function worsened and a re-dosing trigger was met.1

As described in a press release from ProKidney, the US Food and Drug Administration (FDA) previously confirmed during a Type B meeting in Q4 2024 that the accelerated approval pathway is available for rilparencel if an acceptable surrogate endpoint, such as eGFR slope, is used. The Company has an upcoming FDA Type B meeting this summer to confirm the approach to using eGFR slope as the surrogate endpoint for accelerated approval, with additional details expected in mid-2025.1,2

“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, MD, CEO of ProKidney.1 “These data bolster our confidence in the design of our ongoing Phase 3 PROACT 1 study given the similarity between the dosing regimen in REGEN-007 Group 1 and PROACT 1.”

An autologous cellular therapy that received Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA in October 2021, rilparencel is currently being evaluated in the ongoing phase 3 REGEN-006 (PROACT 1) trial to demonstrate the therapy’s potential to preserve kidney function in patients with advanced CKD and type 2 diabetes. Of note, the study protocol was amended in 1H 2024 to focus on a subset of patients with stage 4 CKD and late stage 3b CKD with accompanying albuminuria.1

REGEN-007 is a multicenter, phase 2, open-label, 1:1 randomized 2-arm trial enrolling patients with diabetes, CKD, and an eGFR of 20-50 mL/min/1.73m². At randomization, patients were assigned to 1 of 2 treatment groups using different dosing regimens:

• Group 1 replicated the dosing schedule of the ongoing phase 3 PROACT 1 study in which patients received 2 scheduled rilparencel injections, one in each kidney, approximately 3 months apart
• In Group 2, patients received a single rilparencel injection in 1 kidney and a second injection in the contralateral kidney only if triggered by a sustained eGFR decline from baseline of ≥ 20%, and/or an increase in the urine albumin to creatinine ratio (UACR) from baseline of ≥ 30% and ≥ 30 mg/g

The prespecified primary endpoint for REGEN-007 is the difference in annual eGFR slope in the pre-injection period versus the period following the last rilparencel injection.1

A total of 53 patients were randomized in the study, of whom 49 (mITT population) received ≥ 1 rilparencel injection. Investigators noted the majority of patients were male (69%), had type 2 diabetes mellitus (78%), and the mean age was 60 years. Among the cohort, 80% of patients were receiving an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB) and 37% were receiving a sodium-glucose cotransporter-2 inhibitor (SGLT2i). At baseline, the mean eGFR was 33±10 mL/min/1.73m2. Of note, the median UACR was greater in Group 1 (792 mg/g) than in Group 2 (229 mg/g).1

In Group 1 (n = 24), kidney function stabilized after receiving rilparencel. The annual decline in eGFR slope improved by 78% from -5.8 mL/min/1.73m2 in the pre-injection period to -1.3 mL/min/1.73m2 in the period following the last rilparencel injection, resulting in a statistically significant and clinically meaningful 4.6 mL/min/1.73m2 per year difference (P <.001).1

Investigators noted 63% of the patients in Group 1 met key phase 3 PROACT 1 inclusion criteria, and similar efficacy results were observed in this subgroup compared to the full Group 1 results.1

In Group 2 (n = 25), the annual change in kidney function as measured by eGFR slope was -3.4 mL/min/1.73m2 in the pre-injection period versus -1.7 mL/min/1.73m2 in the period following the last rilparencel injection, resulting in an improvement of 1.7 mL/min/1.73m2 per year. Although this difference was not statistically significant (P = .085), investigators noted it may be indicative of a dose response. Out of the 25 patients in Group 2, 15 (60%) met the re-dosing trigger and received a second rilparencel injection, with a median time between the first and second injections of approximately 11 months.1

No rilparencel-related serious adverse events were observed across all patients in the study who received ≥ 1 rilparencel injection, and the safety profile was consistent with previously reported study results and comparable to a kidney biopsy.1

“We plan to submit the full results from REGEN-007 to ASN’s 2025 Kidney Week as a late-breaking clinical trial and are excited to share more details at that time with investors and the medical community,” said Bruce Culleton, MD, CEO of ProKidney.1 “We also look forward to our upcoming FDA Type B meeting in the coming weeks to confirm our approach to eGFR slope as a surrogate endpoint for accelerated approval. This meeting represents an important step toward our goal of expediting rilparencel’s potential path to market in the US where there remains a significant unmet clinical need in patients with advanced CKD and diabetes.”

References

1. ProKidney. ProKidney Reports Statistically and Clinically Significant Topline Results for the Phase 2 REGEN-007 Trial Evaluating Rilparencel in Patients with Chronic Kidney Disease and Diabetes. July 8, 2025. Accessed July 8, 2025. https://investors.prokidney.com/news-releases/news-release-details/prokidney-reports-statistically-and-clinically-significant

2. ProKidney. ProKidney Reports Third Quarter 2024 Financial Results along with Regulatory and Clinical Development Updates Following Successful FDA Type B Meeting. November 12, 2024. Accessed July 8, 2025. https://investors.prokidney.com/news-releases/news-release-details/prokidney-reports-third-quarter-2024-financial-results-along