'Smart' Cancer Drug Performs Well in Clinical Trials

Experimental treatment uses mRNA expression from tumors to identify responders.

The first-in-human dose escalation study of the experimental treatment BAY 1163877 showed promising in data presented at the European Society of Medical Oncology Congress.

The drug is a pan-fibroblast growth factor receptor (FGFR) inhibitor that uses messenger RNA (mRNA) to identify patients who will respond to treatment.

“Most studies of FGFR inhibitors have looked at FGFR abnormalities in tumors with limited success,” said lead author Markus Joerger, MD, PhD. “This study used an innovative biomarker approach of tumor FGFR mRNA expression.”

BAY 1163877 was analyzed in a total of 80 patients with treatment-refractory locally advanced or metastatic solid tumors. The dose-escalation study was followed by expansion groups in patients whose tumors expressed high FGFR mRNA levels, according to the study.

There were 23 patients in the dose-escalation phase, and 57 patients in expansion groups in bladder cancer, head and neck cancer, lung cancer, and all comers. Patients in the dose-escalation group received 1 of 5 doses (range 50-800 mg twice per day). The researchers did not find any dose-limiting toxicities.

The researchers recommend a dose of 800-mg twice per day based on preclinical trials, the effect on serum phosphate levels, and clinical analyses. A majority of patients developed low-grade hyperphosphatemia, which is common among all patients taking FGFR inhibitors.

A reduced dose of BAY 1163877 could reduce the risk of additional events, according to the study. In the expansion groups, the highest activity of BAY 1163877 was seen in patients with bladder cancer, where there were 3 out of 8 patients who achieved partial remission, the researchers reported.

A few patients with squamous cell lung cancer, squamous cell carcinoma of the head and neck, and adenoid cystic carcinoma achieved partial remissions as well. Patients with adenoid cystic carcinoma achieved remission for more than a year, according to the study.

“BAY 1163877 is a well-tolerated compound with an innovative biomarker approach that effectively identifies patients who have a good chance to benefit,” Joerger said. “Further studies should be conducted, particularly in bladder cancer where about 35% of patients are FGFR mRNA positive.”