(HealthDay News) — For HER2-mutated non-small-cell lung cancer (NSCLC), half of tumors are detected at stage IV, and anti-human epidermal growth factor receptor 2 (HER2) treatments are associated with encouraging response rates and disease control rates (DCRs), according to a study published online April 22 in the Journal of Clinical Oncology.

Julien Mazières, M.D., Ph.D., from the Hôpital Larrey in Toulouse, France, and colleagues collected data on clinicopathologic characteristics, patient outcomes, and treatments for 65 patients with NSCLC, diagnosed with a HER2 in-frame insertion in exon 20.

The HER2 mutation was identified in 1.7% of patients (65 of 3,800) and was exclusive in all but one case. The researchers found that the population had a median age of 60 years; 69% were women, and 52.3% were never-smokers. All the tumors were adenocarcinomas and half were diagnosed at stage IV. Of those diagnosed at stage IV, 16 patients had 22 anti-HER2 treatments administered after conventional chemotherapy. Four, seven, and 11 patients, respectively, had progressive disease, disease stabilization, and partial responses (overall response rate, 50%; DCR, 82%).

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For trastuzumab-based therapies (15 patients) and afatinib-based therapies (three patients), the DCRs were 93% and 100%, respectively, but there was no response to other HER2-targeted drugs. For patients with HER2 therapies, progression-free survival was 5.1 months. For early-stage and stage-IV patients, median survival was 89.6 and 22.9 months, respectively.

“This study, the largest to date dedicated to HER2-mutated NSCLC, reinforces the importance of screening for HER2 mutations in lung adenocarcinomas and suggests the potential efficacy of HER2-targeted drugs in this population,” the authors write.

The study was supported in part by Roche, Boehringer Ingelheim, and GlaxoSmithKline. Several authors disclosed financial ties to the pharmaceutical industry.

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