RTTNews | Jun 29, 2021 05:24PM EDT

17:24 Tuesday, June 29, 2021 (RTTNews.com) - Shares of Altimmune Inc. (ALT) plunged 35% in extended session on Tuesday after the clinical-stage biopharmaceutical company said that its stopping development of its investigational Covid-19 vaccine AdCOVID.

The company decided to discontinue AdCOVID's development after the intranasal vaccine candidate did not stimulate an adequate immune response in healthy volunteers.

"AdCOVID appeared to be well tolerated with an overall adverse event profile similar to intranasal saline placebo. The immunogenicity data demonstrated lower than expected immune responses for each of the immune parameters tested," the company said in a statement.

The company said that antibodies were detected in a subset of subjects, but the response and the percent of subjects responding to AdCOVID were substantially lower than what had been demonstrated for other vaccines already authorized for emergency use.

"The immune response to AdCOVID was inferior to that seen in our NasoVAX influenza vaccine trial," commented Scot Roberts, PhD, Chief Scientific Officer at Altimmune. "Unlike the NasoVAX study, the AdCOVID study population lacked immunity from prior infection or vaccination. We believe that prior immunity in humans may be important for a robust immune response to intranasal dosing with AdCOVID."

The company also decided to terminate further enrollment and evaluate options for future T-COVID development following an assessment of the available data.

ALT closed Tuesday's trading at $15.90, down $0.40 or 2.45%, on the Nasdaq. The stock, further slipped $5.72 or 35.97%, in the after-hours trade.

Read the original article on RTTNews ( https://www.rttnews.com/3205826/altimmune-tanks-35-after-it-discontinues-covid-19-vaccine-development.aspx)

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