FDA puts Altimmune's intranasal COVID-19 vaccine trial on hold

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Altimmune “does not anticipate a significant impact on the overall clinical development timeline." (wildpixel/GettyImages)

The FDA has put a planned phase 1 clinical trial of Altimmune’s intranasal COVID-19 vaccine on clinical hold. Altimmune attributed the setback to the need for protocol modifications and additional chemistry, manufacturing and controls (CMC) data. 

Maryland-based Altimmune is one of a number of companies working on COVID-19 vaccines that are delivered by means other than injection. Altimmune’s candidate, AdCOVID, is an adenovirus type 5-vectored vaccine that is designed to provide protection against SARS-CoV-2 after administration of a single intranasal dose.

Altimmune’s plans to test the vaccine in humans hit a snag late last year when the FDA issued a clinical hold on the IND filing. The FDA asked Altimmune to make protocol modifications and submit additional CMC data to get the clinical hold lifted.

Altimmune has moved quickly to resolve the situation. Having received the letter on Dec. 22, the company had submitted its response to the FDA by the time it publicly disclosed the setback the next day. Altimmune said it has agreed to each of the FDA’s requests.

Given its acceptance of the requests, Altimmune “does not anticipate a significant impact on the overall clinical development timeline.” Altimmune had planned to share early clinical data on the candidate in the first quarter of 2021.

While vaccines from AstraZeneca, Moderna and Pfizer are already approved in some key markets, a group of companies are betting there is an opportunity for next-generation COVID-19 prophylactics. Altimmune’s continued development of AdCOVID reflects a belief intranasal administration has some advantages over the intramuscular vaccines already on the market. Notably, Altimmune designed its vaccine to induce immune responses in the respiratory mucosa central to transmission of the virus.

Shares in Altimmune fell almost 10% after news of the clinical hold broke but have since regained some of the losses.