medwireNews: Adjuvant treatment with osimertinib substantially reduces the risk for central nervous system (CNS) recurrence among patients with resected stage IB–IIIA EGFR-mutated non-small-cell lung cancer (NSCLC), shows an analysis of phase 3 study data.
The exploratory analysis of data from the ADAURA trial, presented at the ESMO Virtual Congress 2020, expands on the preliminary primary analysis, previously reported by medwireNews, which showed that adjuvant osimertinib reduced the risk for recurrence or death by around 80% versus placebo.
For the study, 682 patients with resected stage IB–IIIA NSCLC harboring an exon 19 deletion or L858R mutation in EGFR were randomly assigned to receive postoperative osimertinib 80 mg/day (n=339) or placebo (n=343) for up to 3 years, with adjuvant chemotherapy where indicated.
In all, 11% of patients who received osimertinib experienced a disease-free survival (DFS) event (recurrence or death), of which the majority (62%) were local or regional recurrences and the remainder (38%) distant recurrences.
By comparison, 46% of the placebo group had a DFS event, comprising 39% local/regional recurrences and 61% distant recurrences.
The most common site for recurrence was the lung, occurring at rates of 6% and 18% in the osimertinib and placebo groups, respectively, but the researchers focused their analysis on CNS recurrences because CNS metastases are associated with significant morbidity, reported Masahiro Tsuboi, from the National Cancer Center Hospital East in Kashiwa, Japan.
After a median 22 months of follow-up, the CNS recurrence rate was 1% among the patients who received osimertinib and 10% among those who received placebo. This corresponds to a “clinically meaningful” and “highly statistically significant” 82% reduction in the risk for CNS recurrence, Tsuboi said.
Furthermore, median CNS DFS was not reached among the patients in the osimertinib group but was 48.2 months among those in the placebo group, while the conditional probability of CNS recurrence at 18 months was less than 1% with osimertinib versus 9% with placebo.
Tsuboi concluded: “The reduced risk of local and distant recurrence and improved CNS DFS reinforce adjuvant osimertinib as a highly effective, practice changing treatment for patients with stage Ib/II/IIIA EGFR [-mutated] NSCLC following complete tumor resection.”
In a subsequent discussion, however, Johan Vansteenkiste, from University Hospital KU Leuven in Belgium, stressed that the data are still immature (7% maturity for the current analysis) and said that the DFS rates reported “may not be translated into better cure rates.”
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