Antibody Designed by Spanish Biopharma Oncomatryx Shows That Attacking the Tumor Environment Also Kills Cancer Cells

• A study published in Science Advances shows that OMTX305, an antibody designed by Oncomatryx, destroyed the fibroblasts that protect the tumor in tissue from 15 patients with lung and ovarian cancer, and increased the death of nearby cancer cells.

• The results support the approach the company has pursued for more than fifteen years: treating solid tumors through their microenvironment, not just the tumor cell.

ZAMUDIO, Spain, October 09, 2026--Oncomatryx, the Basque biopharmaceutical company pioneering the treatment of solid tumors through their microenvironment, has taken part, together with German research institutions, in a study showing in patient tumor tissue that destroying the cells that protect the tumor also kills cancer cells.

This was achieved by OMTX305, a bispecific antibody designed by the company that directs the patient's own T cells against the fibroblasts surrounding the tumor. The work is published in Science Advances, a journal of the American Association for the Advancement of Science (AAAS).

Key findings

The study was conducted on slices of freshly resected tumors from 15 patients with lung and ovarian cancer, cultured with the patients' own immune cells. These tissue slices preserve the structure and cell types of the original tumor. The results show that the antibody:

• Activated T cells, particularly those already inside the tumor, and directed them against cancer-associated fibroblasts.

• Destroyed those fibroblasts: the area they occupied fell from 38% to 24% in three days.

• Increased the death of nearby tumor cells in some of the samples. Dying cancer cells were significantly closer to the targeted fibroblasts than those that remained alive.

• Did not bind to healthy human tissues in the analyses performed.

Responses varied between patients. The authors note that clinical trials will need to determine which patient profiles respond most strongly, and point to the tumor's immune profile and, in lung cancer, PD-L1 expression as potential indicators.

"We have seen in real patient tissue, with its own architecture and immune defenses, that attacking the fibroblasts that protect the tumor also kills the cancer cells around them. These are preclinical results that will need to be confirmed in patients, but they reinforce that the microenvironment is a real route to treating cancer," said Myriam Fabre, Chief Scientific Officer of Oncomatryx.

"More than fifteen years ago we bet on attacking cancer through what surrounds it, when almost the entire industry was looking only at the tumor cell. This study shows once again that this path makes sense, and it is the same logic behind the drugs we develop, starting with OMTX705, which is already in clinical trials," said Laureano Simón, founder and CEO of Oncomatryx.