Selecta Biosciences and Cartesian Therapeutics Announce Merger to Form Public Company Focused on RNA Cell Therapy

Selecta Biosciences Joins Forces with Cartesian Therapeutics: Advancing RNA Cell Therapy for Autoimmune Diseases

November 13, 2023 – Selecta Biosciences, Inc. (NASDAQ: SELB) has unveiled a strategic merger with Maryland-based Cartesian Therapeutics, Inc., a clinical-stage biotechnology company that is blazing a trail in the realm of RNA cell therapies for autoimmune diseases.

This new partnership comes with a financial boost, as Selecta also revealed a $60.25 million private financing led by Timothy A. Springer, Ph.D., a member of the Selecta Board of Directors. The result is a combined entity with a financial firepower exceeding $110 million at its disposal, poised to drive the development of Cartesian’s innovative pipeline.

The centerpiece of their collaboration is Descartes-08, a potential game-changer in the treatment of myasthenia gravis (MG). This Phase 2 lead asset has already demonstrated deep and enduring responses in MG patients. The spotlight is on multiple upcoming catalysts, including data from the Phase 2b study of Descartes-08 in MG, expected to surface in mid-2024. Additionally, the merger paves the way for the initiation of multiple studies in various autoimmune indications.

Carsten Brunn, Ph.D., who will continue to serve as President and Chief Executive Officer of the combined company, expressed his enthusiasm, stating, “With several potential value-driving milestones expected in the near-term, including data from the ongoing Phase 2b study of Descartes-08 in MG expected in mid-2024, we are confident that this merger represents a significant opportunity for Selecta stockholders.”

This bold move positions the newly formed company, now named Cartesian Therapeutics, Inc., with a Nasdaq ticker symbol change to “RNAC,” effective November 14, 2023. The merger brings together the expertise of Cartesian’s Co-Founders, Murat Kalayoglu, M.D., Ph.D., and Michael Singer, M.D., Ph.D., who will serve on the Board of Directors.

The legacy Selecta stockholders will receive transferable Contingent Value Rights (CVRs), entitling them to future royalties and milestone payments tied to SEL-212 and all other legacy Selecta assets.

Cartesian Therapeutics offers a portfolio of RNA cell therapies designed for outpatient administration, emphasizing safety, potency, and cost-effectiveness compared to traditional DNA-engineered cell therapies. Their proprietary RNA Armory® platform allows precision control and optimization of engineered cells for various cell therapies, including autologous, allogeneic, and in vivo transfection.

Descartes-08, an autologous anti-BCMA rCAR-T therapy, takes center stage. It is currently in clinical development for MG, a debilitating autoimmune disorder. This revolutionary RNA-engineered therapy promises safety and durability, without the need for preconditioning chemotherapy. Descartes-08 has already been granted Orphan Drug Designation by the U.S. Food and Drug Administration for MG treatment.

Notably, Cartesian reported positive results from a Phase 2a study of Descartes-08, underscoring its safety and efficacy. The ongoing Phase 2b trial is expected to deliver topline results in mid-2024.

Beyond MG, Cartesian is set to initiate a Phase 2 study of Descartes-08 for systemic lupus erythematosus in the first half of 2024, with plans for additional studies in ocular and vasculitic autoimmune diseases later in the year. They are also advancing Descartes-15 and Descartes-33, demonstrating significant promise in the realm of autoimmune therapies.

The merger between Selecta Biosciences and Cartesian Therapeutics heralds a new era in the treatment of autoimmune diseases. It’s a collaboration that promises innovation, progress, and renewed hope for patients in need. Stay tuned for more developments in this exciting biotech venture.

The below information was taken from the company’s press release.

Management and Organization 

The combined company will be led by Selecta’s Chief Executive Officer, Carsten Brunn, Ph.D., and current Chief Financial Officer, Blaine Davis, as well as several members of the legacy Cartesian team, including Metin Kurtoglu, M.D., Ph.D., as Chief Operating Officer, Milos Miljkovic, M.D., as Chief Medical Officer, Chris Jewell, Ph.D., as Chief Scientific Officer, and Emily English, Ph.D., as Vice President of Quality. Matthew Bartholomae, J.D., Selecta’s General Counsel, will continue to serve in this role.

The combined company’s Board of Directors will be led by current Selecta Chairman Carrie S. Cox and will include, among others, current Selecta board member Timothy Springer, Ph.D., as well as Cartesian Co-Founders Murat Kalayoglu, M.D., Ph.D., and Michael Singer, M.D., Ph.D. All members of the Selecta Board of Directors prior to the merger will continue to serve on the Board of Directors following the closing of the transaction.

Merger Terms

The merger was structured as a stock-for-stock transaction pursuant to which all of Cartesian’s outstanding equity interests were exchanged based on a fixed exchange ratio for consideration as a combination of approximately 6.7 million shares of Selecta common stock and approximately 0.38 million shares of Selecta Series A Non-Voting Convertible Preferred Stock (“Series A Preferred Stock”) (or approximately 385 million shares on an as-converted-to-common basis). Concurrently with the acquisition of Cartesian, Selecta entered into a definitive agreement for a PIPE investment to raise $60.25 million in which the investors will be issued approximately 0.15 million shares of Series A Preferred Stock (or approximately 149.3 million shares on an as-converted-to-common basis) at a price of $403.46851 per share.  Subject to approval of the Company’s stockholders, each share of Series A Preferred Stock will automatically convert into 1,000 shares of common stock, subject to certain beneficial ownership limitations. On a pro forma basis, based upon the number of shares of Selecta common stock and Series A Preferred Stock issued in the acquisition and prior to the private financing, stockholders of Selecta immediately prior to the acquisition will own approximately 26.9% of the Company on an as-converted basis immediately after giving effect to this transaction. The acquisition was approved by the Board of Directors of Selecta and the Board of Directors and stockholders of Cartesian. The closings of the transactions are not subject to the approval of Selecta stockholders. On an as-converted basis, assuming the approval of the Company’s stockholders of the conversion of the Series A Preferred Stock into common stock, and after accounting for these transactions, the total number of shares of Selecta common stock will be approximately 696.2 million.

In connection with the transactions, a transferrable contingent value right (a “CVR”) will be distributed to Selecta stockholders and holders of Selecta’s warrants issued in 2022 (the “2022 Warrants”) of record as of the close of business on December 4, 2023, but will not be distributed to holders of shares of common stock or Series A Preferred Stock issued to Cartesian or the PIPE investors in the transaction. Additionally, holders of Selecta’s warrants other than the 2022 Warrants will be entitled to receive CVRs when and if such warrants are exercised. Holders of the CVR will be entitled to receive certain cash payments from proceeds received by the Company, if any, from its legacy assets, including SEL-212, following the closing of the transaction.

Leerink Partners is serving as exclusive financial advisor and private placement agent to Selecta. Covington & Burling LLP is serving as legal counsel to Selecta. Foley Hoag LLP is serving as legal counsel to Cartesian.

Conference Call and Webcast

Selecta and Cartesian will host a conference call today, Monday, November 13, 2023, at 9:00 am ET to discuss the merger. To access the conference call, please dial (844) 845-4170 (local) or (412) 717-9621 (international) at least 10 minutes prior to the start time and ask to be joined into the Selecta Biosciences call. The live audio webcast, along with accompanying slides, can be accessed on the Events & Presentations section of Selecta’s website at A replay of the webcast will be available for a limited time following the event on Selecta’s website.

About Cartesian Therapeutics

Cartesian Therapeutics is a clinical-stage company pioneering RNA cell therapies for the treatment of autoimmune diseases. The company’s lead asset, Descartes-08, is a potential first-in-class, RNA-engineered chimeric antigen receptor T-cell therapy (rCAR-T) in Phase 2b clinical development for patients with generalized myasthenia gravis, with additional Phase 2 studies planned in systemic lupus erythematosus as well as ocular autoimmune and vasculitic autoimmune basket trials. Cartesian operates a wholly owned, state-of-the-art cGMP manufacturing facility in Gaithersburg, MD.

About Selecta Biosciences, Inc.

Prior to the merger discussed herein, Selecta Biosciences Inc. (NASDAQ: SELB) was a clinical-stage biotechnology company leveraging its ImmTOR™ platform to develop tolerogenic therapies that selectively mitigate unwanted immune responses. Selecta Biosciences is headquartered in the Greater Boston area. For more information, please visit