GamaMabs' murlentamab extends PFS in colorectal cancer patients

French biotech firm GamaMabs Pharma has announced positive clinical data from its Phase II study of murlentamab in metastatic colorectal cancer (mCRC), at the European Society of Medical Oncology (ESMO) World Congress on Gastrointestinal Cancer, taking place in Barcelona, Spain.

In combination with trifluridine/tipiracil (FTD/TPI -Servier and Taiho Pharmaceutical’s Lonsurf brand), progression-free survival (PFS) was longer than expected (40% and 31% at 4 and 6 months respectively). This was especially pronounced in patients with more than 20% AMHRII-positive tumor cells, with respectively 83% and 75% patients free of progression at 4 and 6 months. 1.7-fold and 3.6-fold tumor growth rate decrease was observed with murlentamab single agent and murlentamab combined with trifluridine/tipiracil, respectively.

Immune activation under murlentamab was consistently observed in the tumor microenvironment (macrophage and T-cell activation) and in peripheral blood (monocytes and neutrophils activation). No serious adverse events related to murlentamab were reported.

14 patients treated with murlentamab as a single agent (SA) and 15 patients treated in combination with FTD/TPI have been evaluated for efficacy in two parallel non-randomized cohorts.

Results “support further development”
 
“These first clinical and pharmacodynamic data are really encouraging for these patients who have so few options,” said Professor Eric Van Cutsem, University Hospitals Leuven (Belgium), principal investigator of the study. “These results support further development of murlentamab in combination with standard chemotherapies and/or immunological agents in colorectal cancers,” he opined.

“AMHRII expression was found in more than 80% of the tumor biopsied at treatment initiation in the metastatic setting, confirming our previous findings in primary tumors,” said Dr Isabelle Tabah-Fisch, chief medical officer at GamaMabs Pharma, adding: “Besides the encouraging clinical data, the pharmacodynamics changes under murlentamab confirm the rewire of the tumor microenvironment by murlentamab, from macrophage to cytotoxic T lymphocyte activation.”