Osimertinib is effective in pretreated non-small cell lung cancer with EGFR-T790M mutations

This trial examined the effectiveness and safety of osimertinib (Tagrisso) for treating patients with advanced non-small cell lung cancers that harbor T790M mutations. The authors concluded that the drug is promising in both safety and effectiveness at treating this type of cancer.

Non-small cell lung cancers (NSCLC) are commonly caused by genetic mutations (changes). One common mutation is called EGFR. EFGR-TKIs are treatments for patients advanced NSCLC with EGFR mutations. While the initial response to EGFR-TKIs is promising, the majority of patients become resistant to the drugs. This is often because of other mutations, including T790M.

Osimertinib (Tagrisso) is an EGFR-TKI that also targets T790M. Early studies have showed a good response to osimertinib in patients with T790M NSCLC, however further studies need to be performed.

This trial is a further extension of initial studies which examined the effectiveness and safety of osimertinib. The authors assessed effectiveness in terms of objective response rate (ORR – patients with tumor size reduction), progression free survival (PFS – time from treatment until disease progression), disease control rate (DCR – patients with stable or shrinking tumors) and duration of response (DoR – time from initial response until disease progression).

198 patients with advanced NSCLC who progressed after first treatment with EGFR TKIs were included in this trial and treated with osimertinib.

The ORR was 62% and average DoR was 15.2 months. Average PFS was 12.3 months and the disease control rate was 90%.

All patients had at least 1 side effect. The majority of these were mild and included diarrhea, rash, dry skin and infections in the skin around the nails. 3 people died of treatment related side effects, including interstitial lung disease (scarring of lung tissue) and pneumontitis (infection in the air sacs of the lung).

The authors concluded that for patients with T790M advanced NSCLC, osimertinib is safe and effective.

This study was funded by several pharmaceutical companies, including the manufacturers of osimertinib.