Osimertinib shows promise for T790M-positive advanced NSCLC
Osimertinib produced a high objective response rate, as well as a durable response and an “encouraging” PFS among patients with EGFR-mutated T790M advanced non–small cell lung cancer who progressed after EGFR-TKI treatment, according to data from a phase 2 trial.
“The phase 1 component of the osimertinib AURA study showed clinical activity across oral doses of 20 to 240 mg/day,” James Chih-Hsin Yang, MD, PhD, of the National Taiwan University Hospital, Taipei, and colleagues wrote. “The optimal dose chosen for further phase 2 evaluation was 80 mg once daily. The phase 1 study results suggested that both patients with T790M-positive NSCLC and patients with T790M not detected derive benefit from osimertinib treatment but with a much higher response rate in patients with T790M-positive disease (ORR, 61% vs. 21%).”
The researchers performed an extension phase 2 study of 201 patients with EGFR-TKI–pretreated EGFR-mutated and T790M-positive advanced NSCLC. All patients received 80 mg of osimertinib once daily. Yang and colleagues confirmed T790M status with central testing of tumor samples taken after the patients’ most recent disease progression. The researchers allowed patients who had stable, asymptomatic CNS metastases to enroll, as well.
ORR served as the primary objective. Disease control rate, PFS, safety and duration of response served as secondary endpoints.
Median duration of treatment was 13.2 months. Among 198 evaluable patients, ORR was 62% (95% CI, 54-68). The disease control rate was 90% (95% CI, 85-94). In 122 responding patients, median duration of response was 15.2 months (95% CI, 11.3 to not calculable). Overall median PFS was 12.3 months (95% CI, 9.5-13.8).
The most common possibly causally related adverse events were diarrhea (43%; grade ≥ 3, 1%) and rash (40%; grade ≥ 3, < 1%).
“The results from the AURA extension study show that osimertinib 80 mg once daily provides high response rates, encouraging PFS and a long duration of response with a manageable safety profile in patients with T790M-positive pretreated advanced NSCLC,” Yang and colleagues wrote. – by Andy Polhamus
Disclosure: Yang reports honoraria from AstraZeneca, Boehringer Ingelheim, Chugai Pharmaceutical, MSD, Novartis and Roche; and consulting or advisory roles with AstraZeneca, Astellas Pharma, Boehringer Ingelheim, Bayer AG, Bristol-Myers Squibb, Celgene, Clovis Oncology, Daiichi Sankyo, Eli Lilly, Genentech, Merck Serono, MSD, Novartis, Ono Pharmaceutical, Pfizer, Roche and Yuhan. Please see the full study for a list of all other researchers’ relevant financial disclosures.