Headache for Zosano as FDA turns down migraine patch

Zosano Pharma has been hit by an FDA rejection of its marketing application for migraine drug Qtrypta, asking for new bioequivalence data.

Qtrypta takes the form of a transdermal patch loaded with zolmitriptan, a well-established medicine for acute migraine that has been available for years in various formulations including tablets and nasal sprays.

Zosano’s product uses microneedles to help the drug get absorbed into the blood, but the Complete Response Letter (CRL) from the FDA says it is concerned about inconsistencies in how much zolmitriptan was being delivered with Qtrypta.

Specifically, the FDA pointed to differences in zolmitriptan exposures between subjects receiving different lots of Qtrypta in the company's trials, including some unexpectedly high results in five individuals.

It also mentions “inadequate pharmacokinetic bridging between the lots that made interpretation of some safety data unclear.”

The CRL comes just a couple of weeks after Zosano received a discipline review letter (DRL) from the FDA, a preliminary sharing of the agency’s stance, after which the company had already said it did not expect approval by the action date of 20 October.

Shares in the Nasdaq-listed biopharma lost around 25% of their value after the announcement, as investors tried to gauge how long the programme might now be delayed, and the implications for its delivery platform, which is the first microneedle patch to be Included in a new drug application to the FDA.

Qtrypta is Zosano’s lead product candidate, but the company is also working on a follow-up in phase 2/3 for cluster headache.

The FDA wants a new bioequivalence study between three of the Qtrypta lots tested during development, as well as product quality validation data, originally due to be filed after approval, as part of the new drug application (NDA).

The agency also says that inspection of Zosano’s contact manufacturing facilities for the product – while currently on hold because of the pandemic – will also have to be completed before Qtrypta can be approved.

That suggests the delay could be some time, but Zosano is keeping tight-lipped until it has a chance to meet with the FDA to discuss a way forward for the programme.

“We are working diligently to address the deficiencies identified by the FDA and look forward to the possibility of resubmitting our NDA,” said the company’s CEO Steven Lo.

“There are thousands of people suffering from migraine attacks that are not adequately addressed with available drugs, and we continue to believe that Qtrypta, if approved, could offer a much-needed new therapy for these patients,” he added.

The company has previously reported data showing that Qtrypta can deliver fast relief from a migraine with fewer than 2% of patients experiencing side effects common with triptan drugs, like dizziness and pins and needles.

Zosano recently signed a five-year deal worth $250 million deal with Eversana to commercialise and distribute Qtrypta if gets past the FDA.