Why Is Genetic Disease-Focused Alnylam Pharmaceuticals Stock Trading Lower Today?

The FDA has issued a Complete Response Letter (CRL) to Alnylam Pharmaceuticals Inc's ALNY supplemental New Drug Application (sNDA) for patisiran for cardiomyopathy of transthyretin-mediated (ATTR) amyloidosis.

Patisiran, under Onpattro, is approved by the FDA for polyneuropathy of hereditary ATTR amyloidosis in adults. 

In September, the FDA advisory committee voted 9-3 in favor of Alnylam's patisiran. However, the FDA questioned the drug's efficacy in a briefing document. 

For Alnylam's Onpattro application in ATTR-cardiomyopathy, the drug's efficacy data in a phase 3 trial were "small, of questionable clinical meaningful, and may not be detectable by patients," the FDA's drug reviewers said in a briefing document.

The CRL indicated that the clinical meaningfulness of patisiran's treatment effects for the cardiomyopathy of ATTR amyloidosis had not been established.

The CRL did not identify any issues concerning clinical safety, study conduct, drug quality or manufacturing.

As a result of the CRL, the company will no longer pursue an expanded indication for patisiran in the U.S. 

Alnylam 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 cardiomyopathy of ATTR amyloidosis.

It will also be focused on ALN-TTRsc04, which utilizes the company's IKARIA technology, with the potential for greater than 90% TTR knockdown with one annual dosing.

Alnylam intends to maintain the availability of patisiran for patients with the cardiomyopathy of ATTR amyloidosis who are enrolled in the OLE period of the APOLLO-B Phase 3 study and patisiran U.S. expanded access protocol (EAP).

Price Action: ALNY shares are down 8.68% at $161.63 at the last check Monday.

Now Read: Tesla Stock Is Trading Lower: What's Going On?