By Puyaan Singh
July 28 (Reuters) – Benefits of Replimune’s skin cancer drug remain unclear due to flaws in the trial design that make it difficult to determine whether tumor shrinkage was driven by the drug or another therapy, FDA staff reviewers said in briefing documents released on Tuesday.
Shares of the company tumbled 30% in early trading.
Replimune is seeking approval for RP1 in combination with Bristol Myers Squibb’s immunotherapy Opdivo for the treatment of advanced melanoma, a highly aggressive form of skin cancer.
“The FDA review team concludes that this BLA (application) does not include an adequate and well-controlled investigation that demonstrates substantial evidence of effectiveness,” the briefing documents said ahead of the staff’s meeting set for Thursday.
The FDA declined to approve the drug for the second time in two years in April, citing reliance on a single-arm study without a control group, and asked for more data from a well-controlled trial demonstrating adequate evidence of the drug’s effectiveness.
It was one of several contentious actions taken under then-Commissioner Marty Makary, who left the agency after a tumultuous stint that included high-profile disagreements with drugmakers.
“Appreciate the FDA’s decision to convene an advisory committee … we look forward to a constructive dialogue about RP1’s clinical meaningfulness in this difficult-to-treat setting,” Replimune told Reuters.
‘ARTIFACTUALLY INFLATED’ GOALS
The staff added that the contribution of RP1 to the combination effect cannot be determined, and it is unclear if RP1 contributes to any observed effect.
“Replimune likely has an uphill battle … FDA appears to be aligned with its prior assessment laid out in previously published CRLs,” BMO analyst Evan Seigerman said.
The FDA also identified several issues with the application and criteria that were used for response assessment.
The review team concludes that these “artifactually” inflated the main goals of the trial and response rates, the staff said.
However, J.P.Morgan’s Anupam Rana said, “Our thesis remains that Replimune and the physician/patient community will stress the unmet need in refractory melanoma and the overall benefit/risk profile of RP1 (we do sense a lot of support for the product in the physician community based on our channel checks).”
(Reporting by Puyaan Singh in Bengaluru; Editing by Anil D’Silva)
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