Sorrento Therapeutics Inc. has priced its secondary stock offering of 4.765 million shares at $5.25 apiece, with plans to raise net proceeds of $23.1 million.

Sorrento Therapeutics’s (Nasdaq: SRNE) stock has dropped 25 percent since the announcement, from $6.70 on May 14 to $5.00 on May 16.

Sorrento Therapeutics (Nasdaq: SRNE) develops pain medication and cancer drugs, and uplisted last year to the Nasdaq with a $35 million stock offering. In recent months, it has launched a new subsidiary called Ark Animal Therapeutics and acquired a small San Diego biotech called Concortis Biosystems Corp. for about $11.3 million.

Last year, it acquired companies including New York-based Sherrington Pharmaceuticals Inc. and Fountain Valley-based Igdrasol Inc. for undisclosed sums. Sorrento also transitioned to the Nasdaq and recently closed a $35 million stock offering.

Aegis Capital Corp. is acting as the sole book-running manager for the offering.