On Monday, Replimune Group Inc. ( REPL ) is reeling after the FDA unexpectedly rejected its skin cancer treatment, triggering a stock plunge and a wave of investor outrage.

Shares fell sharply Monday on heavy volume, capping a month-long slide of nearly 43%.

At last check, the stock is trading lower with a session volume of 15.96 million compared to the average volume of 7.87 million, as per data from Benzinga Pro.

Over the past month, the stock has declined by almost 43%.

The FDA’s top cancer drug regulator stepped in during the final stages of a heated review of Replimune’s skin cancer treatment — a move that played a key role in the drug being rejected at the last minute, despite support from some within the agency, STAT has learned.

Ongoing leadership changes, staff turnover, and internal issues at the FDA influenced the review process and the decision to deny approval.

Replimune ( REPL ) found itself caught in the middle of the agency’s internal turmoil.

Also Read: Moderna, Merck Reveal Three-Year Data For Individualized Cancer Therapy In High-Risk Melanoma Patients

Most recently, Vinay Prasad, the former director of the U.S. Food and Drug Administration's (FDA) Center for Biologics Evaluation and Research (CBER), resigned within three months of appointment.

Dr. Prasad has openly criticized the biopharmaceutical industry and the FDA for using accelerated approvals broadly based on surrogate endpoints.

For the unversed, in July, Replimmune received an FDA Complete Response Letter (CRL) regarding the Biologics License Application (BLA) for RP1 (vusolimogene oderparepvec) in combination with Bristol-Myers Squibb Co.'s ( BMY ) Opdivo (nivolumab) for advanced melanoma.

The FDA has indicated that the IGNYTE trial is not considered to be an adequate and well-controlled clinical investigation that provides substantial evidence of effectiveness.

Furthermore, the FDA said the trial cannot be adequately interpreted due to the heterogeneity of the patient population.

After the FDA update, Replimmune stock plummeted around 70%.

Soon after, the company was hit with a lawsuit alleging it misled investors by overstating the prospects of its IGNYTE trial, despite knowing—or should have known—of issues that led the FDA to deem the study inadequate and poorly controlled. The complaint claims the company's statements about its business and outlook were materially false or lacked a reasonable basis.

The lawsuit claims that investors suffered damages when the true details entered the market.

Price Action: REPL stock is down 27.9% at $5.48 at the last check on Monday.

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