FDA deals blow to Incyte's PD-1 retifanlimab after battering advisory panel meeting

Incyte snuck out some bad news Friday night: Afterhours, the Wilmington, Delaware-based biopharma said it had been hit with an FDA complete response letter for its experimental checkpoint inhibitor retifanlimab.

The company is seeking a license for the intravenous PD-1 inhibitor to treat adult patients with locally advanced or metastatic squamous cell carcinoma of the anal canal (SCAC) who have progressed on, or who are intolerant of, platinum-based chemotherapy.

Retifanlimab was granted a speedy review back in January with a decision date of July 25. A month ago, however, the FDA’s oncology committee assessed the drug, saying it needed more data from the ongoing test, known as POD1UM-303, a confirmatory trial in platinum-naïve advanced SCAC, before it could recommend approval.

The committee flagged many concerns, including a lack of diversity in trial participants, several deaths attributed to the therapy and its effectiveness. A CRL was largely expected after the battering report from the committee, which voted 13-4 to defer a decision.

Specifically that letter, which is not published by the FDA but comes via Incyte, says that “additional data” is needed in order to prove the clinical benefit of retifanlimab.

“Incyte is reviewing the letter and will discuss next steps with the FDA,” the company said in a statement, with little more detail given on timings.

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Incyte secured global rights to retifanlimab, then known as MGA012, from MacroGenics for $150 million upfront back in 2017. Having seen many PD-1 rivals corner major indications over the past half decade, Incyte picked out a clutch of niche tumors in which to validate retifanlimab and get it registered, while also exploring some more common diseases and in combination with the company's other oncology drugs.

Incyte has been putting a bigger emphasis on SCAC than the clutch of companies that have already won FDA approval for PD-1/L1 drugs did. Checkpoint inhibitors are already used as second-line treatments of metastatic anal cancer, with the National Comprehensive Cancer Network adding Merck’s Keytruda and Bristol Myers Squibb’s Opdivo to its guidelines in 2018, but the data to support them are limited. 

Keytruda and Opdivo secured their positions on the treatment guidelines on the strength of clinical trials that enrolled 24 and 37 patients, respectively. Merck went on to test Keytruda in 112 more patients, but Incyte still sees an opportunity for retifanlimab. That has now been dealt a major blow.

“Patients with SCAC who have progressed after first-line chemotherapy currently do not have approved treatment options,” said Hervé Hoppenot, CEO of Incyte. “While we are not surprised with the FDA decision given the ODAC recommendation, we are disappointed.

“We remain committed to advancing science to find solutions for patients with unmet medical needs, and we will ensure close coordination with the FDA in order to address feedback and determine next steps for the review of retifanlimab.”