Solu Therapeutics Secures $41M Series A Financing to Advance Novel CyTAC and TicTAC Platforms Targeting Intractable Cell Surface Proteins

BOSTON, April 9 – Solu Therapeutics, a biotechnology company pioneering novel medicines that eliminate disease-driving cells in oncology, immunology, and other therapeutic areas, announced the successful completion of a $41 million Series A financing round. The round included participation from five new investors—Eli Lilly and Company, Biovision Ventures, Pappas Capital, Hengdian Group Capital (HgC), and The Leukemia & Lymphoma Society Therapy Acceleration Program®—along with continued support from existing investors Longwood Fund, DCVC Bio, Santé Ventures, Astellas Venture Management, and Alexandria Venture Investments. The company also announced the dosing of the first patient in its first-in-human Phase 1 clinical trial evaluating STX-0712 in patients with resistant/refractory chronic myelomonocytic leukemia (CMML) and other hematologic malignancies.。（New Frontier! $31 Million Seed Funding to Develop Bifunctional Small Molecules）

Philip J. Vickers, President and CEO of Solu Therapeutics, said:"In the short time since our initial seed funding, Solu Therapeutics has rapidly evolved into a clinical-stage company committed to addressing highly unmet medical needs for patients. Through this Series A financing, we appreciate the continued support from our existing investors and are thrilled to welcome several new investors who recognize the potential of our novel CyTAC (Cytotoxic Targeted Chimera) and TicTAC (Therapeutic Index-Controlled Targeted Chimera) platforms. These technologies demonstrate unprecedented capabilities to unlock high-value cell surface targets that traditional antibodies cannot reach, enabling more precise and effective elimination of disease-driving cells."

The proceeds from the Series A financing will be used to complete dose escalation and expansion of the leading CCR2-CyTAC program, STX-0712, for the treatment of CMML. Additionally, the funds will support the generation of a new pipeline of development candidates, including a novel, first-in-class mast cell depleting agent for immune disorders, initiate new discovery programs targeting pathogenic cells, further expand the pipeline, and explore new applications for the CyTAC and TicTAC platforms.Solu Therapeutics is developing three different TicTAC projects for potent and long-acting sodium channel antagonists. One project specifically targets NaV1.7, while anotherThe project targets NaV1.8, the thirdThe project aims to dual inhibit NaV1.7 and NaV1.8.

By uniquely linking potent and selective small molecules with effector antibodies, cell surface proteins that are undruggable by other therapeutic modalities can be targeted. Using best-in-class small molecule binders, it is possible to access deep binding pockets within receptors such as G-protein coupled receptors (GPCRs) and ion channels. Solu Therapeutics designs the binders as bifunctional small molecules. One arm engages the extracellular target, while the other arm connects to a proprietary antibody using innovative linker technology. This cutting-edge linker technology enables Solu Therapeutics to create an entirely new class of drugs where bifunctional small molecules adopt the pharmacokinetic properties and functionality of antibodies. This unique ability to combine bifunctional small molecules with antibodies allows for the development of novel therapeutics that were previously impossible to create.

CyTAC™：Cytotoxicity Targeting Chimera

Proprietary CyTAC molecules connect cell surface targets that label pathogenic cells with a proprietary platform antibody that induces the killing of these cells.

TicTAC™：Therapeutic Index Control Targeting Chimera

Proprietary TicTAC molecules facilitate the tight binding of potent and selective small molecule agonists or antagonists with Fc-modified antibodies, imparting antibody-like pharmacokinetic properties to the small molecules. This can offer multiple advantages, providing better characteristics for therapeutic applications.

STX-0712 aims to selectively deplete CCR2-positive malignant monocytes in patients with advanced hematologic malignancies, with an initial focus on CMML. The Phase 1 trial of STX-0712 is an open-label, multicenter study divided into two parts. Part A will focus on dose escalation to determine the maximum tolerated dose and/or minimal effective dose, enrolling participants with refractory/resistant CMML. Part B will further evaluate the safety, tolerability, recommended Phase 2 dose, and preliminary anti-tumor activity of STX-0712.

Sergio Santillana, M.D., Chief Medical Officer of Solu Therapeutics, stated:"Our team is excited to initiate the first-in-human clinical trial of STX-0712, marking a significant step forward in our mission to develop innovative therapies for patients with unmet medical needs. By directly depleting CCR2-positive malignant monocytes that drive CMML, STX-0712 has the potential to offer a highly specific and targeted treatment for patients with currently limited therapeutic options. This trial represents an important milestone for Solu Therapeutics as we strive to bring new and potentially more effective targeted therapies to patients with CMML and other hematologic malignancies."

In December 2024, Solu Therapeutics presented preclinical data at the 2024 American Society of Hematology (ASH) Annual Meeting, showing that STX-0712 has potent in vitro activity against CCR2-positive monocytes in CMML patient samples. CMML is characterized by elevated monocyte counts and bone marrow dysplasia, with limited treatment options.