Treatment with targeted therapy osimertinib following surgery for localised non-small cell lung cancer (NSCLC) with an epidermal growth factor receptor (EGFR) mutation significantly improved disease-free survival in a phase III study.

Of patients with stage II-IIIA NSCLC who received osimertinib, 90% were alive at two years without the cancer recurring, compared with 44% who received a placebo.

In stage II-IIIA patients, the risk of disease recurrence or death was reduced by 83% for patients treated with adjuvant osimertinib after surgery compared to placebo.

Results of the multinational randomised controlled phase III ADAURA trial were compelling enough that the independent data monitoring committee recommended early unblinding.

The findings come from an unplanned interim analysis to be presented as part of the virtual scientific program of the 2020 American Society of Clinical Oncology (ASCO) Annual Meeting.

“This trial is a home run. It exceeded our expectations,” said lead author Roy S. Herbst, MD, PhD, who is the Chief of Medical Oncology at Yale Cancer Center and Smilow Cancer Hospital, and the Associate Cancer Center Director for Translational Research at Yale Cancer Center.

“It’s an important advance to see a targeted therapy significantly delay disease recurrence following surgery in patients with non-small cell lung cancer. We can now treat patients earlier.”

Adjuvant chemotherapy is standard of care in patients with stage II-III NSCLC who have undergone complete tumour resection and select patients with stage IB disease; however, recurrence rates are high.

Osimertinib is a third-generation EGFR tyrosine kinase inhibitor and is approved in the United States for first-line treatment of patients with metastatic NSCLC with tumours that have EGFR mutations (exon 19 deletions or exon 21 L858R mutations).

Results from this trial show efficacy in the adjuvant setting for patients with earlier stage disease and the same EGFR mutations.

Patients with stage II-IIIA had an 83% reduction in the risk of disease recurrence or death.

Disease-free survival at 2 years was 90% with osimertinib compared with 44% with placebo in patients with stage II-IIIA NSCLC with an EGFR mutation.

In the overall population (stage IB- IIIA), treatment with osimertinib reduced the risk of disease recurrence or death by 79% compared to placebo.

Disease-free survival at 2 years was 89% with osimertinib compared with 53% with placebo.

Overall survival, a secondary endpoint, was immature at the time of data analysis.

The safety profile in this study was consistent with the known safety profile of osimertinib, and the drug was generally tolerable.

Source: ASCO

Watch ecancer's interview with Prof Herbst here.