FDA rejects ViiV HIV drug on CMC grounds

ViiV Healthcare, the HIV joint venture GSK and Pfizer set up in 2009, expected to win US Food and Drug Administration (FDA) approval for its long-acting cabotegravir and rilpivirine product shortly before the end of last year. However, the FDA issued a complete response letter days before its decision was due.

In disclosing the setback, ViiV revealed the FDA rejected the drug due to issues related to the chemistry, manufacturing and controls (CMC) portion of the submission. ViiV said the safety profile of the product, which is branded Cabenuva, is unchanged.

ViiV is yet to share details of the CMC issues that led the US FDA to issue the complete response letter. The nature of Cabenuva makes it impossible to identify one facility implicated in the problem on the basis of the publicly available information.

GSK has previously said its production site at Barnard Castle in the UK will support the introduction of a long-acting treatment for HIV. However, one component of the two drug regimen, rilpivirine, is being developed by Johnson & Johnson, which already sells an oral formulation of the ingredient as Edurant.

ViiV’s statement suggests it will be able to resolve the issues that led to the US FDA rejection without generating new clinical data. Even so, some CMC issues can significantly delay approval.

GSK needs a quick resolution to the problem to deliver on its HIV strategy. Talking to investors in October, ViiV chairman David Redfern said future growth in HIV will come from two-drug oral and injectable regimens. Cabenuva is ViiV’s pitch for the injectable market.

As a product that is injected every four or eight weeks, Cabenuva is clearly differentiated from the daily oral regimens that currently dominate the market. Cabenuva performed comparably to oral, three-drug regimens in clinical trials, leading Redfern to express excitement about its potential to improve the lives of some patients.

Redfern said, “It won't be for every patient. I think there have been a lot of patients happy to continue on oral therapy. But for those patients that are interested in moving, they're very passionate about it​.”

Those patients will have to wait longer to switch to an injectable regimen. ViiV had expected to win approval late in 2019 and throw its marketing muscle behind the drug this year. Now, the timeline will be dictated by the outcome of ViiV’s talks with the FDA about the next steps for the filing.