ProNAi Therapeutics, Inc. (DNAI)

ProNAi Therapeutics was a clinical-stage cancer drug developer. Its lead candidate, PNT2258, was based on the company's DNA interference platform, which used short DNA strands designed to block the expression of the BCL2 gene, a driver of certain lymphomas. The company tested the drug in diffuse large B-cell lymphoma and other blood cancers. The company had no approved products and depended on investor funding.

ProNAi went public on NASDAQ in July 2015, selling 8.1 million shares at $17.00 under the symbol DNAI and raising about $138 million. The offering was well received and the stock rose in early trading. The company had research roots in Michigan and its operations were run from Vancouver, British Columbia. It was among the larger biotech offerings of that summer.

In 2016 trial data for PNT2258 fell short of expectations and the company stopped developing it. Management then licensed new oncology programs, including a CHK1 inhibitor, and in January 2017 renamed the business Sierra Oncology, with the shares moving to the ticker SRRA. Sierra later in-licensed momelotinib, a drug for anemic patients with myelofibrosis, which became its focus. Its earlier lymphoma work was wound down.

After positive late-stage results for momelotinib, GSK agreed in April 2022 to buy Sierra Oncology for $55.00 per share in cash, about $1.9 billion. The deal closed on July 1, 2022 and the stock was delisted. GSK later won approval for momelotinib under the brand name Ojjaara. Shareholders received cash and no longer hold any listed successor shares of Sierra.