Alnylam Posts Positive Phase 2 Results for its RNAi Nephropathy Drug

On August 29, Alnylam announced positive results from its Phase 2 trials studying the safety and efficacy of cemdisiran, an investigational RNA interference (RNAi) drug to treat immunoglobulin A nephropathy (IgAN). The Cambridge-based company is developing the drug alongside Regeneron Pharmaceuticals, and based on the most recent data; the two hope to push cemdisiran into Phase 3 trials. 

Optimistic Results on the Heels of Phase 3 Trials

Alnylam’s RNAi candidate, cemdisiran, is designed to treat the rare kidney disorder, IgAN, which affects about 2.5 out of 100,000 Americans annually. IgAN is an inflammatory disease that damages the glomerulus, which acts as the filtering unit for the kidney. The disease can progress into kidney failure causing lifelong issues and potentially death. 

Cemdisiran is an RNAi drug designed to target the C5 component of the complement pathway via subcutaneous injection. The complement system is part of the immune system that enhances the antibodies’ and phagocytic cells’ ability to regulate cell damage and promote inflammation. 

The Phase 2 trial’s main focus centered around demonstrating favorable effects on proteinuria, a high protein level in urine. Proteinuria is a strong risk factor associated with disease progression in IgAN. In the trial, cemdisiran demonstrated a 37% reduction in 24-hour urine protein to creatinine ratio relative to the placebo, satisfying the study’s primary endpoint. 

New data also showed that cemdisiran met several secondary endpoints, which included extra measures of proteinuria, percent of patients with partial remission, and frequency of adverse events. Alnylam did not publish partial remission rates, but the company noted that the patients tolerated the drug well with minimal adverse events. The most significant adverse events were injection site reactions and peripheral edema, or swelling of the lower legs and hands.

Sonalee Agarwal, Ph.D., Vice President and Program leader for cemdisiran at Alnylam, said, “IgAN is an inflammatory disease that can lead to severe loss of kidney function. Thus, given the persistent unmet need in the treatment landscape of this progressive disease, we, together with our partners at Regeneron, are working expeditiously to advance this investigational RNAi therapeutic into Phase 3 clinical development.”

Related Article: Ocelot’s Rare Kidney Disease Candidate Receives Orphan Drug Designation Going Into Phase 2 Trials

Closing in on the Competition

If cemdisiran eventually makes it to market, it would be the second FDA-approved drug to treat IgAN, following Calliditas Therapeutics’ Tarpeyo, which received accelerated approval in December last year. As part of the Accelerated Approval Program, Calliditas will have to perform postapproval trials to prove the drug slows kidney function decline in IgAN patients. According to the FDA’s Postmarket Requirements and Commitments database, Calliditas has not started a confirmatory trial yet. 

Going through the regular drug approval route, if Alnylam can bring cemdisiran to market, it has a better chance of maintaining its approval status compared to Tarpeyo, which risks withdrawal if it does not complete confirmatory trials or if confirmatory trials demonstrate negative results. However, if there is a more effective and thoroughly vetted IgAN treatment on the market, Calliditas might feel more pressure to perform confirmatory trials or risk withdrawal. 

However, these speculations are still in the distance as Alnylam must progress through Phase 3 trials while maintaining cemdisiran’s positive results. The most recent Phase 2 results are hopeful for future results, though, and the company is sure to put more effort into the drug’s development to make it their fifth approved product. 

Author

Reed Slater