Alnylam Pharmaceuticals, Inc. (NASDAQ:ALNY) announced today topline results from the Phase 2 study of cemdisiran, an investigational RNAi therapeutic targeting the C5 component of the complement pathway that is in development in collaboration with Regeneron Pharmaceuticals for the treatment of immunoglobulin A nephropathy (IgAN). At Week 32, treatment with cemdisiran resulted in a 37 percent mean reduction from baseline in the 24-hour urine protein to creatinine ratio relative to placebo – the primary endpoint of the study and an important prognostic marker of disease progression. The results of secondary endpoints were also consistent with a therapeutic benefit of cemdisiran in IgAN. There were no significant drug-related safety signals. We believe these collective efficacy and safety data support continued clinical development of cemdisiran monotherapy in patients with IgAN.
“We are encouraged by these topline results with cemdisiran demonstrating what we believe to be clinically meaningful reductions in proteinuria – an important prognostic factor in IgA nephropathy. IgAN is the most common inflammatory disease affecting the glomerulus of the kidney. It can progress to end-stage kidney disease, if left untreated,” said Sonalee Agarwal, Ph.D., Vice President and Program Leader for the Cemdisiran program at Alnylam. “Given the limited treatment options and significant unmet need in IgAN, we, together with our partners at Regeneron, are formulating our plans for the Phase 3 clinical development of cemdisiran.”
The Phase 2 study enrolled a total of 31 patients who were on stable doses of angiotensin converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB); nine were randomized to placebo and 22 to cemdisiran. The primary endpoint of the study was the percent change in the 24-hour urine protein to creatinine ratio (UPCR) at Week 32. Secondary endpoints at Week 32 included:
- Percent of patients with partial clinical remission (urine protein <1g/24-hours)
- Percent of patients with >50% reduction in 24-hour proteinuria
- Percent change from baseline in 24-hour proteinuria (g/24-hours)
- Change from baseline in UPCR as measured in spot urine
- Change from baseline in hematuria
- Frequency of adverse events (AEs)
This Phase 2 study was descriptive only and did not include statistical hypothesis testing. Treatment with cemdisiran led to a 37 percent (90% CI: 0, 61) mean reduction in 24-hour urine protein to creatinine ratio relative to placebo. All secondary efficacy endpoints trended in favor of cemdisiran, supporting the therapeutic hypothesis. There were no serious or severe adverse events (AEs) related to study drug, and the overall safety and tolerability profile of cemdisiran supports continued clinical development. One death was reported in the cemdisiran arm due to a post-surgical complication; this was not considered related to study drug by the investigator. There were no discontinuations from study drug due to AEs. Two of nine (22 percent) patients on placebo and 12 of 22 (55 percent) of patients on cemdisiran experienced treatment emergent AEs that were related to study drug.