FDA rejects approval of Adamis' Zimhi for opioid overdose; shares tumble 60%

Shares in Adamis Pharmaceuticals plunged as much as 60% on Monday after the company announced that the FDA issued a complete response letter regarding its filing for the investigational high-dose naloxone product Zimhi to treat opioid overdose. "We are very surprised and disappointed," remarked CEO Dennis Carlo, adding "we believe the comments and recommendations stated in the [complete response letter] are manageable and plan to fully cooperate with the FDA."

According to Adamis, the agency's concerns "related generally" to chemistry, manufacturing and controls (CMC), while no other clinical safety or efficacy problems were flagged. Adamis indicated that it plans to "expand on the CMC testing that has already been provided to the FDA" in order to satisfy the issues.

The agency was initially expected to render its decision by October 31. "With a growing number of fatal overdoses as a result of more potent opioids like fentanyl, we believe there is an obvious need for higher dose forms of naloxone," Carlo said, adding the company would seek a meeting with the FDA "as soon as reasonably possible" to discuss plans to resubmit the application.

Last month, Adamis presented data comparing Zimhi to doses of naloxone products currently on the market, including kaléo's hand-held auto-injector Evzio and Emergent BioSolutions' nasal spray formulation Narcan, as well as generic naloxone. Adamis said Zimhi led to significantly higher and more rapid levels of naloxone in the blood compared to the other products.

Adamis and kaléo settled litigation between the companies earlier this year, including a case filed by the latter in US district court claiming that Zimhi infringed some of its patents. Kaléo has also announced plans to introduce an authorised generic version of Evzio this year that would cost $178 per two-pack carton, compared to more than $4000 for the branded product.

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