In preclinical studies in mice, QTX153 reduced body weight without loss of muscle mass, and the company is preparing to start its first Phase I clinical trial in 2027.
ZAMUDIO (Bizkaia), 8th October 2026 – Quimatryx, the chemistry subsidiary of Oncomatryx, has developed QTX153, an oral drug candidate for the treatment of obesity that, in preclinical studies, reduced body weight without reducing muscle. The results were presented on 30 September at the 62nd Annual Meeting of the European Association for the Study of Diabetes (EASD 2026), held in Milan from 28 September to 2 October, as part of the congress’s oral session program.
In mice with diet-induced obesity, QTX153 given orally once a day reduced body weight by 19.2% over 22 days at the highest dose, compared with 21.2% for injectable semaglutide in the same study. The weight loss came from a reduction in visceral fat, while skeletal muscle weight was maintained. Current obesity drugs such as semaglutide are highly effective, but part of the weight patients lose is muscle mass. Preserving muscle during weight loss is one of the goals obesity research is currently working towards.
Beyond weight loss, the compound improved glucose tolerance and reduced liver fat and markers of liver damage. In the preclinical studies conducted to date, it has also shown high oral bioavailability and a favorable safety profile.
“These are preclinical results and there is still a way to go, but the fact that QTX153 reduces weight without reducing muscle, orally and through a different mechanism from current treatments, encourages us to keep working on its development,” said Eneko Aldaba, Director of R&D and co-founder of Quimatryx.
Unlike incretin-based therapies such as semaglutide, QTX153 is a selective inhibitor of HDAC6, an enzyme involved in leptin signaling. Leptin is a key hormone in the regulation of appetite and energy balance. The study was carried out in collaboration with the Kaertor Foundation and the University of Santiago de Compostela, with the participation of Oncomatryx researchers. Quimatryx is now completing the regulatory preclinical studies for QTX153, which will allow it to start its first Phase I clinical trial in 2027.
“QTX153 shows that the chemistry capability we have built for our cancer drugs can generate valuable candidates beyond oncology. Cancer remains our focus, but our platform is designed precisely for this: to generate multiple drugs and take each one as far as it can bring value to patients,” said Laureano Simón, Founder and CEO of Oncomatryx.
More information about the congress is available at: https://www.easd.org/annual-meeting/easd-2026/
About Quimatryx
Quimatryx is the Basque medicinal chemistry company of the Oncomatryx group. Since 2025, it has carried out the conjugation chemistry for the group’s antibody-drug conjugates (ADCs) in its own laboratories: it designs the linker and the payload and conjugates the complete ADC. This chemistry expertise also enables it to develop its own drug candidates in other therapeutic areas.
About Oncomatryx
Oncomatryx is a Spanish biopharmaceutical company headquartered in the Basque Country with a global outlook, and a pioneer in treating metastatic solid tumors by targeting their microenvironment rather than the tumor cell. The company has also built a platform designed to generate multiple drug candidates and advance them to clinical proof of concept for licensing to large pharmaceutical companies. This platform spans the full cycle of research, clinical development and in-house manufacturing that defines today’s industry leaders.
Oncomatryx is the only biotech company designated as a strategic company by Spain’s Centre for the Development of Industrial Technology (CDTI). In 2025, it received a European Union EIC Accelerator grant as one of five life sciences companies selected from 950 applicants.