The third-generation targeted agent osimertinib (Tagrisso, AstraZeneca) has now been granted a full approval by the US Food and Drug Administration (FDA) after showing a significant improvement in progression-free survival (PFS) when compared to chemotherapy in a randomized clinical trial in a specific group of patients with non‒small cell lung cancer (NSCLC).
The drug has been available in the United States since November 2015, when it was granted an accelerated approvalon the basis of overall response rates in two single-arm clinical trials.
Osimertinib is indicated for use in patients with metastatic NSCLC that is positive for the epidermal growth factor receptor (EGFR) T790M mutation who have experienced disease progression on first-line treatment with an EGFR inhibitor.
The manufacturer emphasizes that the presence of an EGFRT790M mutation in a tumor specimen or plasma specimen (if tumor tissue is unavailable) should be confirmed through use of an FDA-approved test prior to initiation of treatment.
The full approval is based on results from the AURA3 (NCT012151981) study, conducted in 419 patients with metastatic NSCLC who were EGFR T790M‒positive and had experienced progression on first-line EGFR inhibitor therapy. These patients were randomly allocated in a 2:1 ratio to receive osimertinib 80 mg orally once daily or platinum-based doublet chemotherapy.
Patients in the chemotherapy arm received pemetrexed (Alimta, Lilly) with either carboplatin or cisplatin on day 1 of every 21-day cycle for up to 6 cycles, followed by pemetrexed maintenance therapy. Patients who experienced disease progression while receiving chemotherapy were offered therapy with osimertinib.
The results showed a significant benefit for the targeted therapy. The estimated median PFS was 10.1 months with osimertinib compared to 4.4 months with chemotherapy (hazard ratio, 0.30; P < .001). The estimated median durations of response were 11 months with osimertinib compared to 4.2 months for chemotherapy.
The data on overall survival are not yet mature, the manufacturer notes.
The company also notes that serious adverse reactions were evaluated in 833 patients who received osimertinib. The most serious were interstitial lung disease/pneumonitis (3.5%), QTc interval prolongation (0.7%), cardiomyopathy (1.9%), and keratitis (0.7%). The most common adverse reactions (occurring in at least 20% of patients) were diarrhea, rash, dry skin, nail toxicity, and fatigue.