NantKwest, a US-based immune-oncology company backed by pharmaceutical companies Celgene and Sorrento, closed its initial public offering at $238.3m on Friday.
The company initially raised $207m last week when it issued almost 8.3 million shares on Nasdaq priced at $25 each. Its $2.6bn market cap was reportedly the largest ever in a biotechnology IPO.
NantKwest raised an additional $31m when underwriters BofA Merrill Lynch, Citigroup Global Markets, Jefferies, Piper Jaffray and MLV & Co took up the option to buy another 1.24 million shares. Its stock is trading at $27.66 at the time of publication.
Originally founded in 2002, NantKwest is developing immunotherapy drugs to treat cancer, infectious diseases and inflammatory diseases. Part of the IPO proceeds will fund Phase I and I/II clinical trials for three of its product candidates.
Celgene paid $17m for about 680,000 shares in the offering. Sorrento retains a stake sized at about 7% after investing $11m in the company in December 2014.