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# Alnylam Gets ‘Complete Response’ on sNDA
- URL: https://www.fdaweb.com/alnylam-gets-complete-response-on-snda/
- Published: 2023-10-09T12:00:00.000Z
- Updated: 2026-09-14T19:01:24.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5155514

FDA has issued Alnylam Pharmaceuticals a complete response letter on a supplemental NDA for Onpattro (patisiran) for treating cardiomyopathy of transthyretin-mediated (ATTR) amyloidosis. Onpattro was approved in 2018 to treat hereditary ATTR amyloidosis polyneuropathy, and the sNDA rejection has no affect on the original approval, according to the company.

The complete response came despite a 9/13 FDA Cardiovascular and Renal Drugs Advisory Committee vote of 9 to 3 that patisiran’s benefits outweigh its risks for the expanded indication. It appears agency medical reviewers dismissed the vote and remained skeptical of patisiran’s efficacy in treating a larger pool of patients as sought in the company’s sNDA. In a [briefing document ](https://www.fda.gov/media/171977/download?ref=fdaweb.com)released in advance of the committee meeting, FDA said that while the APOLLO-B study submitted with the sNDA was well designed and executed and met a key primary endpoint and a key secondary endpoint, with the results being statistically significant, the reviewers found that “the effects of patisiran compared to placebo on both endpoints were small, of questionable clinical meaningfulness, and may not be detectable by patients.”

The FDA letter indicated that the clinical meaningfulness of patisiran’s treatment effects had not been established, the company acknowledged. It did not identify any issues with clinical safety, study conduct, drug quality or manufacturing, the company adds.

Alnylam says it will no longer pursue an expanded indication for patisiran in the U.S. “The company remains dedicated to the ATTR amyloidosis community and will continue to focus on the HELIOS-B Phase 3 study of vutrisiran, an investigational RNAi therapeutic subcutaneously administered once every three months in development for the treatment of the cardiomyopathy of ATTR amyloidosis, and ALN-TTRsc04, which utilizes the company’s IKARIA technology, with the potential for greater than 90% TTR \[transport protein transthyretin \] knockdown with once annual dosing,” it says.