Osimertinib plus Chemotherapy for Non-Small Cell Lung Cancer with Mutated EGFR
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Reviewed & Translated by Dat Tien Nguyen, B.A, ScM.
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Posted on February 2nd, 2026
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Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Prior studies have demonstrated that osimertinib is more effective in treating non–small cell lung cancer than earlier-generation EGFR inhibitors and platinum-based chemotherapy. Separately, recent evidence has shown that combining platinum-based chemotherapy with the second-generation EGFR inhibitor gefitinib leads to improved clinical outcomes compared with gefitinib alone. Building on these findings, a study funded by AstraZeneca was conducted to evaluate whether adding platinum-based chemotherapy to osimertinib could further improve outcomes.
This phase 3 clinical trial enrolled 557 patients with previously diagnosed locally advanced or metastatic nonsquamous non–small cell lung cancer. All participants had tumors harboring activating EGFR mutations, specifically exon 19 deletions or L858R substitutions. Patients with stable central nervous system metastases were eligible for inclusion, although the exact number of such patients was not specified.
Participants were randomly assigned to receive either osimertinib plus platinum–pemetrexed chemotherapy or osimertinib monotherapy. Osimertinib was administered orally at a daily dose of 80 mg and functions by inhibiting downstream EGFR signaling, thereby suppressing tumor cell proliferation. In the combination arm, patients received pemetrexed at 500 mg per square meter of body surface area along with a platinum agent, either cisplatin or carboplatin.
After a median follow-up of 51 months, patients treated with the combination regimen demonstrated improved overall survival, with a 23% lower risk of death compared with those receiving osimertinib alone. The authors hypothesized that EGFR-mutated adenocarcinomas may be particularly sensitive to pemetrexed due to lower expression of thymidylate synthase, a key target of the drug that helps tumor cells survive & proliferate. However, the combination therapy was associated with a higher incidence of adverse events, many of which were severe and led to treatment discontinuation. As a result, clinicians must carefully balance the survival benefit against the increased toxicity when selecting therapy. The researchers also noted that alternative adjunctive strategies, including angiogenesis inhibitors and antibody–drug conjugates, may offer additional avenues to improve clinical outcomes.
This phase 3 clinical trial enrolled 557 patients with previously diagnosed locally advanced or metastatic nonsquamous non–small cell lung cancer. All participants had tumors harboring activating EGFR mutations, specifically exon 19 deletions or L858R substitutions. Patients with stable central nervous system metastases were eligible for inclusion, although the exact number of such patients was not specified.
Participants were randomly assigned to receive either osimertinib plus platinum–pemetrexed chemotherapy or osimertinib monotherapy. Osimertinib was administered orally at a daily dose of 80 mg and functions by inhibiting downstream EGFR signaling, thereby suppressing tumor cell proliferation. In the combination arm, patients received pemetrexed at 500 mg per square meter of body surface area along with a platinum agent, either cisplatin or carboplatin.
After a median follow-up of 51 months, patients treated with the combination regimen demonstrated improved overall survival, with a 23% lower risk of death compared with those receiving osimertinib alone. The authors hypothesized that EGFR-mutated adenocarcinomas may be particularly sensitive to pemetrexed due to lower expression of thymidylate synthase, a key target of the drug that helps tumor cells survive & proliferate. However, the combination therapy was associated with a higher incidence of adverse events, many of which were severe and led to treatment discontinuation. As a result, clinicians must carefully balance the survival benefit against the increased toxicity when selecting therapy. The researchers also noted that alternative adjunctive strategies, including angiogenesis inhibitors and antibody–drug conjugates, may offer additional avenues to improve clinical outcomes.