Selecta fuses with Cartesian in reverse merger, bolstering finances for autoimmune cell therapy goals

Selecta Biosciences is jumping into Cartesian’s cell therapy cockpit, preparing to take flight once again after landing nearly all of its previous programs. 

The two companies announced a reverse merger Monday, with Selecta shareholders owning 26.9% of the new company. The merged company will keep Cartesian's name and will be listed as "RNAC" on NASDAQ, with Selecta CEO Carsten Brunn, Ph.D., taking the helm. Cartesian’s co-founders Murat Kalayoglu, M.D., Ph.D., and Michael Singer, M.D., Ph.D., will join the board. 

The new Selecta will have over $110 million in cash moving forward, including $60.2 million from a private placement also announced this morning. That’s enough to advance the lead asset, an RNA-engineered CAR-T from Cartesian called Descartes-08, through a phase 3 trial to treat myasthenia gravis. A phase 2 trial testing the treatment in patients with lupus is expected to launch in the middle of 2024. The merged biotech says the new funds will also help afford additional programs. 

The move offers both Selecta and Cartesian a magical ingredient that’s been fleeting for many biotechs this year: hope. 

Selecta’s ambitions had dwindled down to one asset following an announcement in August that it was narrowing its focus to its Sobi-partnered gout drug, SEL-212, with plans to submit an FDA approval application in 2024. Other programs, like the company’s preclinical ImmTOR-IL asset for liver diseases, were paused. The few prospects were reflected in the company’s share price, which has lived below $2 per share since March. Over the summer the company said it would lay off 25% of the team to fortify its finances. 

Cartesian has been chugging along well as it advanced the Descartes-08 therapy, but as many private biotechs know all too well, the financing environment has been stringent. Now the asset serves as a lighthouse hoping to draw in sustained public investment. 

Beyond Descartes-08, Cartesian comes equipped with Descartes-15, a preclinical, next-generation version touted as “significantly more potent” based on early research. The biotech is also working on an off-the-shelf stem cell therapy Descartes-33, to treat autoantibody-associated autoimmune diseases. 

Editor's note: This story was updated to correct that the merged company will keep Cartesian's name, not Selecta's.