CTO1681 to prevent and mitigate cytokine release syndrome in multiple myeloma patients receiving car T-cell therapy

The National Cancer Institute awarded Cytoagents Inc. $1,313,567 on September 22, 2025, under the Cancer Treatment Research program (CFDA 93.395) to develop and advance CTO1681, a pharmaceutical compound designed to prevent and mitigate cytokine release syndrome in multiple myeloma patients receiving CAR T-cell therapy.

CTO1681 is an orally available compound that reduces transcription of proinflammatory cytokines implicated in cytokine release syndrome, a severe systemic inflammatory response associated with chimeric antigen receptor T-cell therapy. The compound is identical to beraprost sodium-314D, the active stereoisomer of beraprost sodium, which modulates cytokine release from human peripheral blood mononuclear cells. Cytoagents has investigated the use of this compound for both CAR T-cell therapy-induced CRS and virus-induced moderate CRS, specifically in influenza and COVID-19.

Cytoagents Inc., a for-profit pharmaceutical development company based in Pittsburgh, Pennsylvania, is the recipient. The award period runs through August 31, 2027, with place of performance in Pennsylvania. The Cancer Treatment Research program supports development and evaluation of improved cancer treatment methods, including biological therapy and molecular targeted therapies, along with studies to reduce toxicity of cytotoxic therapies.

Abstract

Cytoagents is developing CTO1681 for the prevention and treatment of cytokine release syndrome (CRS) associated with chimeric antigen receptor (car) T-cell therapy. Car T-cell therapy has emerged as a very promising treatment option for patients with relapsed or refractory (R/R) hematologic malignancies. However, car T-cell therapy can also result in a high incidence of severe and potentially life-threatening immune-mediated toxicity, including CRS and immune effector cell-associated neurotoxicity syndrome (ICANS). CRS is a systemic inflammatory response that has been reported as one of the most frequent and dangerous adverse events following CD19-directed car T-cell therapy. CRS is thought to be mediated by an initial release of proinflammatory cytokines, which activate bystander immune cells and endothelial cells, which in turn activate more immune cells, culminating in a cytokine storm. Because cytoagents' novel approach is focused on reducing the transcription of multiple proinflammatory cytokines, its compound is expected to mitigate, and in some cases even prevent, CRS. CTO1681 is an orally available, stable compound identical to beraprost sodium-314D (BPS-314D), the stereoisomer of the racemate beraprost sodium (BPS) that accounts for nearly all of BPS's pharmacological activity. Because BPS can modulate the release of cytokines from human peripheral blood mononuclear cells, cytoagents has investigated the use of BPS and its active isomer CTO1681 as a treatment for moderate virus-induced CRS, specifically influenza and covid-19. All of the results to date indicate that CTO1681 has strong potential to reduce the CRS response, leading to better patient outcomes regardless of CRS etiology. Overall, BPS, BPS-314D, and CTO1681 formulations have been found to be well tolerated and to not completely suppress cytokine levels in healthy volunteers with normal serum levels. Cytoagents is currently conducting a phase 1B trial of CTO1681, a multicenter, open-label, dose-escalating safety and pharmacokinetic (PK) MAD study in patients with diffuse large B cell lymphoma (DLBCL) receiving CD19- directed car T-cell therapy. This direct to phase II project will support additional drug manufacturing and initiation of an open-label phase 2A trial in multiple myeloma (MM) patients. The company will undertake three specific aims: 1) determine the preliminary efficacy of CTO1681 in preventing or reducing CRS or ICANS compared to historical data; 2) determine the expanded safety profile of CTO1681 in patients with R/R MM receiving car T-cell therapy; 3) investigate the potential impact of CTO1681 on antitumor activity of car T-cell therapy compared to historical data. This project will help support clinical assessment of CTO1681 in car T-cell therapy recipients, advancing a novel treatment with the potential to reduce hospitalization, intensity of supportive care, and mortality and to improve patients' quality of life. Moreover, this therapeutic may allow more patients with R/R hematologic malignancies to have access to potentially life-saving car T-cell treatment.