Shares for San Diego-based Vical Inc. plunged 57 percent after the drugmaker announced its melanoma treatment failed in clinical trials.

Stock was trading at $1.52 per share at market close August 12, a $2.05 drop from the previous trading day. The decrease places Vical’s market capitalization at $132.7 million.

Vical (NasdaqGS: VICL) said in an investor call that it was ending clinical trials of its anti-melanoma drug, Allovectin, and will focus instead on developing vaccines for infectious diseases. Allovectin had been under development for nearly 20 years.

“In the coming weeks, we will make the necessary changes to focus resources on our infectious disease vaccine programs and reduce expenses to conserve cash,” CEO Vijay Samant said.

He said that Allovectin’s failure “does not diminish the potential for success” for the company’s remaining drugs. The company reported cash and investments of $70 million on June 30, which it said is enough to meet its needs through the end of 2014.

— Meghana Keshavan