Sunesis Pharmaceuticals

Sunesis Pharmaceuticals, Inc. operated as a biopharmaceutical firm with a focus on developing and commercializing treatments for hematologic and solid cancers. Founded in 1998, the company built its operations around internal research and development, strategic in-licensing and out-licensing of pharmaceutical compounds, and managing clinical trials.

Historically, Sunesis's pipeline included several drug candidates. One of its key programs was vosaroxin, an anti-cancer quinolone derivative designed to treat acute myeloid leukemia (AML). The company also developed vecabrutinib, a non-covalent inhibitor of Bruton's Tyrosine Kinase (BTK) intended for patients with B-cell malignancies who had developed resistance to other BTK inhibitors. Another significant asset was SNS-510, a PDK1 inhibitor licensed from Millennium Pharmaceuticals (a subsidiary of Takeda Oncology), which showed potential in treating a variety of cancers, including those of the breast, lung, and prostate. Sunesis's business model involved advancing these candidates through clinical trials and forming licensing agreements. For instance, it had a licensing deal with Denovo Biopharma for vosaroxin and another with DOT-1 for a pan-Raf inhibitor program, which entitled Sunesis to milestone payments and royalties.

In a significant strategic shift, Sunesis entered into a definitive merger agreement with Viracta Therapeutics, Inc. in November 2020. This all-stock transaction, which closed in February 2021, resulted in the formation of a combined entity operating under the name Viracta Therapeutics, Inc. and trading on Nasdaq under the ticker "VIRX". Following the merger, pre-merger Sunesis shareholders owned approximately 13.95% of the new company, while Viracta shareholders held the remaining 86.05%. The merged company's focus pivoted to Viracta's pipeline, particularly its lead program targeting Epstein-Barr virus (EBV)-positive malignancies. This program features an all-oral combination therapy of nanatinostat and valganciclovir. After the merger, the Sunesis name and its original operational focus were discontinued, and the new entity, Viracta Therapeutics, began to carry forward the mission of developing treatments for virus-associated cancers. However, the Viracta Therapeutics, Inc. website now states that the company is no longer operating.

Keywords: Sunesis Pharmaceuticals, Viracta Therapeutics, biopharmaceutical, oncology, hematologic cancers, solid tumors, vosaroxin, acute myeloid leukemia, vecabrutinib, BTK inhibitor, SNS-510, PDK1 inhibitor, clinical trials, drug development, pharmaceutical licensing, merger, acquisition, Viracta, nanatinostat, Epstein-Barr virus, EBV-positive lymphoma