Spectrum Pharmaceuticals, Hanmi Pharmaceutical's U.S. partner, said that it is further expanding its poziotinib clinical program by adding three new cohorts for ZENITH20, a global phase 2 trial for the drug.

The ZENITH20 trial is an open-label, multicenter, global phase 2 trial evaluating the impact of poziotinib treatment on non-small cell lung cancer (NSCLC) patients.

"Amid the increased use of osimertinib as the treatment of first-line NSCLC patients with classical epidermal growth factor receptor (EGFR) mutations, the emergence of osimertinib resistance is a growing occurrence in this setting," said Jeffrey Clarke, assistant professor of medicine at Duke University Hospital.

One emerging resistance pattern is through the development of an additional EGFR mutation, and recent pre-clinical publications suggest that poziotinib may be active against EGFR-dependent resistance mechanisms, he added

The three new cohorts are currently open to patient enrollment in the ZENITH20 trial.

Cohort 5 includes previously treated or treatment-naïve NSCLC patients with EGFR or HER2 exon 20 insertion mutations, Cohort 6 includes NSCLC patients with classical EGFR mutations who progressed while on treatment with the first-line osimertinib and developed an additional EGFR mutation, and Cohort 7 includes NSCLC patients with a variety of less common mutations in EGFR or HER2 exons 18-21 or the extracellular or transmembrane domains.

"Our poziotinib clinical program is aggressive, proactive and designed to provide us with a full understanding of poziotinib's potential impact on non-small cell lung cancer," Spectrum Pharmaceuticals President and CEO Joe Turgeon said. "Thus far, we are pleased with the rapid recruitment and are eagerly awaiting our first topline readout in patients with previously treated EGFR exon 20 insertion mutations in the fourth quarter of this year."