On August 6, 2025 Galapagos NV (Euronext & NASDAQ: GLPG) reported that the United States Food and Drug Administration (FDA) has granted RMAT designation to GLPG5101, a second generation anti-CD19/4-1BB CAR-T product candidate for the treatment of relapsed/refractory mantle cell lymphoma (R/R MCL) (Press release, Galapagos, AUG 6, 2025, View Source [SID1234654864]).

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The RMAT designation was established under the U.S. 21st Century Cures Act to accelerate development and review of promising cell and gene therapies for serious or life-threatening conditions. To qualify for RMAT designation, GLPG5101 demonstrated preliminary clinical evidence suggesting it has the potential to treat, modify, reverse, or cure a serious or life-threatening disease.

Clinical data derived from the ongoing ATALANTA-1 study with GLPG5101 in patients with R/R B-cell Non-Hodgkin Lymphoma (B-NHL), including a subset of patients with MCL, supported the RMAT designation. These data1 demonstrated both high objective and high complete response rates, with a manageable safety profile, including low rates of high-grade cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS) and low dropout rates.

"This designation reflects the promising clinical activity and safety profile observed in our ongoing Phase 1/2 study and supports our commitment to delivering an effective and timely treatment option to patients in need," said Omotayo Fasan, M.D., Clinical Development Program Head at Galapagos. "With RMAT status allowing for closer collaboration with the FDA, this will enable additional opportunities for accelerated development and assessment timelines."

Benefits of RMAT designation include increased FDA guidance and more frequent interactions during development, eligibility for accelerated approval based on surrogate or intermediate endpoints, all Fast Track and Breakthrough Therapy advantages such as priority review and rolling submissions, and early discussions of potential study endpoints.

Galapagos intends to report updated data from the ATALANTA-1 study at a future medical conference.

About GLPG5101 and ATALANTA-1

GLPG5101 is a second generation anti-CD19/4-1BB CAR-T product candidate, administered as a single fixed intravenous dose. The safety, efficacy and feasibility of decentralized manufactured GLPG5101 are currently being evaluated in the ATALANTA-1 Phase 1/2 study in eight hematological malignancies with high unmet need. The primary objective of the Phase 1 part of the study is to evaluate safety and to determine the recommended dose for the Phase 2 part of the study. Secondary objectives include assessment of efficacy and feasibility of decentralized manufacturing of GLPG5101. The dose levels that were evaluated in Phase 1 are 50×106 (DL1), 110×106 (DL2) and 250×106 (DL3) CAR+ viable T-cells. The primary objective of the Phase 2 part of the study is to evaluate the Objective Response Rate (ORR) while the secondary objectives include Complete Response Rate (CRR), duration of response, progression free survival, overall survival, safety, pharmacokinetic profile, and the feasibility of decentralized manufacturing. Each enrolled patient will be followed for 24 months. The ATALANTA-1 study is currently enrolling patients in the U.S. and Europe.

About relapsed/refractory mantle cell lymphoma

Mantle cell lymphoma is a rare and aggressive subtype of non-Hodgkin lymphoma originating from B cells. Patients with relapsed or refractory disease have progressed after standard therapies and face limited treatment options and reduced survival rates.