Daiichi Sankyo closed its Plexxikon branch in south San Francisco earlier this year. Now, a new startup is looking to chart its own course — with 10 Plexxikon veterans, five now-defunct biotech assets, and a focus around a new target.
Opna Bio, led by former Plexxikon CEO Gideon Bollag, announced its emergence from stealth this morning – combined with a $38 million Series A round.
Plexxikon, acquired by Daiichi in 2011 for $935 million, was shut down earlier this year as the Japanese pharmaceutical company planned to streamline efforts to continue R&D on Enhertu and two other ADCs. The company, which was founded more than two decades ago, has pushed two cancer therapies all the way through the FDA: Zelboraf in partnership with Roche for melanoma and Turalio for tenosynovial giant cell tumors in 2019.
Opna Bio, according to Bollag, was founded in 2019 – and there are more ties to Bola’s former company, Onyx Pharmaceuticals, than Plexxikon. Douglas Hanahan, one of Opna’s co-founders and head of the biotech scientific advisory board, knew Bollag from his time at Onyx.
“And really independently of Plexxikon, at the very beginning of the pandemic, when I was still CEO of Plexxikon, Doug called and got this news and asked me if I would be interested in it, and looked it over. It was very exciting,” Bollag said.
What that story was about — and what sets Opna apart from other biotech — is a protein called fragile X messenger ribonucleoprotein, or FMRP, and its use in oncology drug development. Hanahan and his laboratory published an article last week in Science on the protein expressed in cancer and hypothesize that it is involved in helping tumor cells evade the immune system.
The protein, encoded by the FMR1 gene, has normally been associated with neurons, says Bollag Terminal news. However, as Hanahan and the lab pointed out, increased levels of FMRP have been noted in some cancers, including pancreatic, colon, breast, prostate, and lung cancers.
This finding led Hanahan’s lab to try to find out why cancer cells express it – because normally they shouldn’t be able to, Bollag pointed out. And it turns out that FMRP is a master regulator of mRNA translation and stability – and it plays a role in the immune system detecting cancer. In addition, it could help in the treatment of certain immune cancers against checkpoint inhibitors.
Bollag added that the idea is that if this protein can be blocked by a small molecule, then the host’s immune system should be much more capable of pursuing and destroying the tumour.
So far, the shortlisting and selection of candidates is still ongoing.
In addition to this effort, Opna Bio said it has acquired five oncology candidates from Plexxikon, including two clinical-stage programs. One, the BET inhibitor OPN-2853, is in a Phase I/II trial for myelofibrosis, and the other (OPN-7486) is a CSF1 inhibitor slated for Phase II next year. The remaining three candidates are still in preclinical development.
In the meantime, the 15-person biotech says it aims to find a partner, and that sneaking out will allow the company to have more discussions with as many interested parties as possible. And speaking of the $38 million the company has raised via Series A, that will last Opna well into 2024.
Investors in this round included Longitude Capital, Northpond Ventures and Menlo Ventures.