Patients with rare EGFR exon 20 mutation, accounting for about 10 percent of non-small-cell lung cancer patients, might get their disease treated with a new therapy, a study showed Tuesday. EGFR, or epidermal growth factor receptor, is a transmembrane protein. Mutations affecting EGFR expression could lead to cancer.

Dr. John Heymach, a professor at the University of Texas MD Anderson Cancer Center, announced the result of his study at the World Conference on Lung Cancer in Yokohama, Japan, saying poziotinib was more effective than the existing EGRF tyrosine kinase inhibitors (TKI).

“Poziotinib showed superior efficacy in non-small-cell lung cancer patients with exon 20 mutation than existing EGFR TKIs. The study also confirmed the possibility that the drug could be actively effective on patients with cancerous cells spread to the central nervous system and leptomeningeal carcinomatosis,” Heymach was quoted as saying by Hanmi Pharmaceutical, one of the developers of poziotinib.

Poziotinib showed more than 40 times stronger potency than TKIs and 80 percent tumor shrinkage on genetically engineered mouse (GEM) models and patient-derived xenograft (PDX) models.

The MD Anderson Cancer Center is conducting a phase-2 clinical trial on 60 lung cancer patients with exon 20 mutation. As of Tuesday, the study’s objective response rate marked 73 percent or eight out of 11 study patients.

“Patients who suffer from EGFR exon 20 mutation have a poor prognosis with median progression-free survival (PFS) of less than two months on first-generation TKIs,” Heymach was quoted as saying. “However, it was remarkable that all 11 study patients who received poziotinib at a 16mg daily dose have seen tumor shrinkage, as well as evidence of activity in the central nervous system.”

Currently, about 10 percent of non-small-cell lung cancer patients with EGFR mutation suffer from exon 20 mutation. However, no cure has been developed to treat the disease to date.