CREATE Medicines and Amsterdam University Medical Center Initiate First In Vivo CAR Therapy Trial in Frontline Setting for Solid Tumors

• MT-302, a TROP2-targeting mRNA-LNP in vivo CAR therapy, is the first treatment of its kind to move into a frontline solid tumor trial
• Study builds on clinical experience from over 40 patients, one of the largest clinical datasets in the in vivo CAR field

CAMBRIDGE, Mass., Oct. 28, 2025 /PRNewswire/ -- CREATE Medicines, Inc., formerly Myeloid Therapeutics, Inc. ("CREATE"), announced today that Amsterdam University Medical Center ("Amsterdam UMC") has dosed the first patient in the SPaCE-MT clinical trial. The trial will evaluate the treatment of advanced gastroesophageal cancer with CREATE's MT-302 with capecitabine, oxaliplatin (CAPOX) with or without nivolumab or trastuzumab, representing the first clinical evaluation of an in vivo CAR therapy combined with a standard frontline regimen for solid tumors.

This trial marks a pivotal step in advancing in vivo immune programming to unlock truly scalable, off-the-shelf cell therapies. With this milestone, CREATE Medicines is one step closer to realizing its vision for the future of in vivo cell therapy through repeat-dose treatments that expand access and integrate seamlessly with existing standards of care.

"In vivo mRNA CARs represent a new class of programmable medicines, and SPaCE–MT brings this modality into frontline care. The early MT–302 data demonstrate safety and activity that support combination therapy – expanding options and meaningfully improving outcomes for patients," said Daniel Getts, Chief Executive Officer of CREATE Medicines.

Professor Hanneke van Laarhoven, leading scientist on the trial and Medical Oncologist and Head of the Department of Medical Oncology at Amsterdam UMC - Cancer Center in the Netherlands, recognizes that MT-302 has significant potential to enhance frontline therapy and improve outcomes for patients with advanced esophageal and gastric cancers. The research team is eager to discover new insights into how this therapy may positively influence outcomes for patients with various types of cancer.

In Vivo CAR Clinical Validation

In vivo CAR therapies have become one of the most closely watched frontiers in oncology, offering the potential to overcome the manufacturing complexity, cost, and scalability limitations of traditional ex vivo CAR-T approaches. CREATE has distinguished itself by generating one of the largest clinical datasets in the in vivo CAR field across multiple Phase 1 studies:

• Proof-of-mechanism: Paired biopsies confirmed CAR+ immune cells infiltrating tumors, with immune remodeling and CD8 T-cell recruitment.
• Safety data and repeat dosing: Over 200 monotherapy doses administered with a consistent, manageable safety profile and no cumulative toxicities observed to date.
• Evidence of activity: CAR expression detected in circulating immune cells, stable disease in several patients, and a confirmed partial response lasting 16 months.

These results provide compelling human validation for CREATE's mRNA-LNP platform and de-risk next-generation multi-cell programming initiatives.

"The initiation of this study underscores the need for innovative treatment strategies in gastroesophageal cancer, where outcomes still remain very poor," said Matt Maurer, Chief Medical Officer, CREATE Medicines. "By combining our in vivo CAR therapy with established chemotherapeutic and immunotherapy treatments, we aim to unlock the full potential of a coordinated immune attack against cancer."

About SPaCE-MT

SPaCE-MT (Safety and Preliminary Clinical Efficacy of MT-302 with CAPOX-based Regimens in Metastatic Esophagogastric Cancer, EUCT 2024-520213-45-00) is an open-label, Phase 1/2 investigator-initiated trial led by Professor Hanneke van Laarhoven at Amsterdam UMC. The study evaluates the safety, tolerability, and preliminary efficacy of MT-302 in combination with CAPOX with or without nivolumab or trastuzumab in patients with advanced gastroesophageal cancer.

About Gastroesophageal Cancer

With over 1.3 million new cases diagnosed globally each year, gastroesophageal cancers remain a leading cause of cancer-related mortality worldwide. While progress has been made with chemotherapy, targeted agents, and immune checkpoint inhibitors, outcomes for patients with advanced gastroesophageal cancer remain poor, and resistance to frontline therapies is common, underscoring the urgent need for novel treatment approaches.

About MT-302

MT-302 is a first-in-class, TROP2-FcA-LNP therapy that programs immune cells directly in vivo to attack tumors. TROP2 is overexpressed in most epithelial cancers, with limited expression in normal tissues. Unlike antibody-drug conjugates, MT-302 elicits a coordinated immune response by engaging innate and adaptive arms, including presentation of tumor neoantigens to T cells.

About Amsterdam UMC - Cancer Center Amsterdam

Amsterdam UMC is a leading medical center that combines complex high-quality patient care, innovative scientific research, and education of the next generation of health care professionals. We believe that health care practice, research and education belong together, with each shaping and informing the other. With over 16,000 people, the two locations of Amsterdam UMC work together to provide good and accessible care. Cancer Center Amsterdam is an academic oncology center within Amsterdam UMC that aims to create groundbreaking new possibilities for patients with cancer. It integrates care, research, valorisation, and education in the field of cancer. The Department of Medical Oncology within Cancer Center Amsterdam focuses on new and existing treatments, personalization of treatment and supportive care.

About CREATE Medicines

CREATE Medicines (formerly Myeloid Therapeutics) is a clinical-stage biotech pioneering in vivo multi-immune programming. Its proprietary mRNA-LNP platform directly programs immune cells inside the body to deliver scalable, repeat-dose, off-the-shelf immunotherapies. With proven human validation and next-generation RNA technology, CREATE is advancing a pipeline of in vivo CAR therapies to transform outcomes in cancer, autoimmunity, and fibrosis.
For more, visit createmedicines.com. Follow us on LinkedIn and X (Twitter).

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Media Contact: Susan Roberts, [email protected] | +1 (202) 779-0929

Investor Contact: Brian Korb, [email protected] | +1 (917) 653-5122

SOURCE CREATE Medicines, Inc.