With Marina Biotech's back against the wall, the RNAi drugs field may soon see the departure of its third player this year, following the bankruptcy of Traversa Therapeutics and the acquisition of Tacere Therapeutics by Benitec Biopharma.
Marina has been under severe financial strain for nearly a year, prompting it to shut down all its day-to-day activities in June (GSN 6/7/2012). Earlier this month, the company disclosed that it only has enough funds to carry it to the end of the month and may be forced to cease operations (see related story, this issue).
Marina's possible shutdown comes on the heels of news that Benitec is buying Tacere, a company that had been founded by former Benitec executives, along with its preclinical hepatitis C virus therapy (GSN 10/11/12). Tacere had been primarily focused on advancing the HCV drug through a partnership with Pfizer, but that relationship was ended when Pfizer decided to end its in-house involvement in oligonucleotide therapeutics early last year.
A Benitec official this week confirmed that the company would be maintaining Tacere, but that all of its employees have left expect Tacere's director of research and development, David Suhy, who has become Benitec's new senior vice president of R&D.
And, as exclusively reported by Gene Silencing News, Traversa filed for bankruptcy this year after it was unable to generate sufficient financing, with portions of its technologies sold off to former employees (GSN 5/31/2012).
Though this quick succession of exits from the field is uncommon, the RNAi space has experienced a number of other disappearing acts over the past decade.
The most successful is undoubtedly Sirna Therapeutics, which was once the field's top player alongside Alnylam Pharmaceuticals, but in early 2007 sold itself to Merck for $1.1 billion (GSN 1/4/2007). Though Sirna remained a subsidiary of Merck, about a year ago the big pharma subsumed the RNAi drug shop (GSN 8/5/2011).
Acuity Pharmaceuticals remains just a footnote in RNAi drug history as the first company to develop a phase III siRNA drug, having merged with two other companies, including a publicly traded shell corporation, to become Opko Health in 2007 (GSN 3/29/2007).
Today's Opko bears little resemblance to Acuity, with an entirely different management and a focus that includes ostensibly no RNAi activities.
Two other early RNAi drug players, Atugen and Intradigm, also no longer exist after both being acquired by Silence Therapeutics. In 2005, Atugen was bought for $7.5 million by British biotech SR Pharma, which later changed to Silence. Four years later, Silence bought Intradigm (GSN 12/17/2009), though it recently closed down Intradigm's California operations to cut costs.
Cequent Pharmaceuticals is also gone from the ranks of RNAi drug developers after it was acquired by Marina in 2010, largely for its transkingdom RNAi technology, which uses attenuated Escherichia coli to transcribe therapeutic shRNAs and gave rise to Marina's sole clinical candidate, the familial adenomatous polyposis treatment CEQ508 (GSN 4/1/2010).
Not all changes to the RNAi therapeutics firm roster have been voluntary, however.
Former expressed RNAi high flier Nucleonics was forced to shut down after failing to secure necessary capital. A lawsuit between the company's founders and management later revealed that the funding woes were prompted by allegations of scientific misconduct (GSN 11/6/2008).
New Zealand's Genesis Research and Development, meantime, has been maintaining virtually no RNAi drug-development operations after failing to generate compelling enough data from its preclinical single-stranded RNAi programs to woo investors (GSN 5/6/2010).