Final analysis of a phase II, open label, randomized study of osimertinib versus osimertinib plus carboplatin/pemetrexed for patients with locally advanced or metastatic non-small cell lung cancer whose disease has progressed with previous EGFR-TKI and whose tumours harbour a T790M mutation (LOGIK1604/NEJ032A).

e21594 Background: Osimertinib is now available not only as a second line treatment for the patients with EGFR and T790M-mutation positive non-small cell lung cancer (NSCLC) after initial tyrosine kinase inhibitors (TKIs) but as a first line treantment for those who are TKI-naive. The efficacy and the safety of osimertinib plus palatinum-based chemotherapy has not yet been evaluated. Methods: This phase 2, open-label, randomized study enrolled adult patients (pts) with clinical stage IIIB or IV, or postoperative recurrent NSCLC harbouring susceptible EGFR and T790M mutations after preceded EGFR-TKI failure. Pts were randomly assigned to receive either an osimertinib [80 mg/day 1-21; q3w] or a combination of osimertinib [80 mg/day 1-21] with carboplatin/pemetrexed (hereafter combination) [area under the curve (AUC) = 5 and 500 mg/m2 day 1; q3w]. The primary endpoint was progression-free survival (PFS). Secondary endpoints included incidence of adverse events, response rate and overall survival. As indiction of osimertinib was expanded to a first line, we amended the protocol to discontinue the enrollment and perform final analyses. Results: From October 2016 to January 2019, 62 pts were enrolled [31 pts osimertinib; 31 pts combination] (median age 68 (37-80); 53.2% male; 83.3% stage IV; 100% adenocarcinoma; 59.7% exon 19 deletion and 40.3% L858R; 45.2% never smoker). The rate of grade (G) ≥ 3 treatment-related adverse events was 32.2% in the osimertinib group and 83.9% in the combination group. Neutropenia, anemia and thrombocytopenia were more common in the combination group and the rates of G ≥ 3 were 0%, 0% and 6.4% in the osimertinib group and 38.7%, 25.8% and 29.1% in the combination group, respectively. Three episodes (9.7%) of G ≥ 3 infection and one episode (3.2%) of G ≥ 3 febrile neutropenia were uniquely observed in the combination group, however, these were well managed. Two episodes (6.5%) of G ≥ 3 pneumonitis was observed only in the osimertinib group. Exaggeration of adverse events specific for osimertinib or any unknown adverse event was not observed in the combination group. Final PFS analysis is to be demonstrated in the presentation. Conclusions: Combination of osimertinib with carboplatin and pemetrexed demonstrated safety in patients with EGFR and T790M mutation-positive NSCLC and the efficacy should be validated in the future phase 3 study. Clinical trial information: 000024438.