Extended follow-up data from the ADAURA study reveal that the benefit of adjuvant osimertinib over placebo in persons with EGFR-mutated stage IB-IIIA non-small-cell lung cancer remains beyond the 3-year treatment course (NSCLC).
Masahiro Tsuboi of the National Cancer Center Hospital East in Kashiwa, Japan, remarked at the ESMO Congress 2022 in Paris, France, that the “new findings strengthen adjuvant osimertinib as the standard of care for [these patients] following total tumour resection, with or without adjuvant chemotherapy.”
The primary analysis of the phase 3 trial found that using adjuvant osimertinib 80 mg once daily for up to 3 years was associated with an 83% lower risk of disease recurrence or death in patients with stage II-IIIA disease (the primary endpoint) and an 80% reduction in those with stage IB-IIIA disease versus placebo.
With an extra 2 years of follow-up, the median DFS in this updated analysis was 65.8 months in the 233 people with stage II-IIIA illness who received osimertinib and 21.9 months in the 237 who received placebo. The median duration of follow-up was 44.2 and 19.6 months, respectively.
The difference in risk for disease progression or mortality between the two arms was 77% lower in favour of osimertinib. At 3 years, osimertinib had a DFS rate of 84% versus 34% with placebo, and at 4 years, the rates were 70% and 29%, respectively.
According to Tsuboi, the results show that osimertinib “continued to demonstrate a clinically meaningful DFS benefit.”
A similar pattern was observed for central nervous system DFS in the primary study cohort (hazard ratio [HR]=0.24) and overall DFS in the whole study cohort (stage IB-IIIA; HR=0.27), with osimertinib favouring all outcomes, including those in subgroup analyses.
During the long follow-up period, which comprised a median of 35.8 months of osimertinib exposure, no additional safety issues were detected, according to the presentation.
This is the most interesting slide for the #ADAURA trial.
Here you can find the rate of local PD vs distant
Local/regional not well specified but should include lung and LN https://t.co/A5bcCttNFe pic.twitter.com/sNxQHA2XhA
— Antonio Passaro MD PhD (@APassaroMD) September 19, 2020
Sanjay Popat, a session discussant from the Royal Marsden NHS Foundation Trust in London, UK, stated that “the DFS impact remains strong and clinically impactful.”
“Adjuvant osimertinib remains, however arguable, [an] important therapy choice for our patients, despite the lack of mature overall survival data,” he added.
However, he noted that in patients with stage II and IIIA illness, the survival curves appear to reveal the first evidence of a putative tyrosine kinase inhibitor decreasing effect after therapy termination. The effect was less noticeable in patients with stage IA illness, but Popat speculated that this could be due to a lack of occurrences.
“Given this diminishing efficacy,” he says, “the ideal osimertinib duration in stage II and IIIA illness is unknown.”
He went on to say that it’s unclear “if osimertinib is just delaying recurrence and whether longer adjuvant osimertinib (more than 3 years) dosage is indeed required vs treatment on relapse.” Furthermore, “the possible diminishing effect strongly suggests for treatment with adjuvant chemotherapy when necessary.”
Popat concluded that he is eager to see further data on long-term disease-free survival, recurrence patterns over time, outcomes by minimal residual disease, and overall survival.
Springer Healthcare Ltd. provides an independent medical news service called medwireNews. Springer Healthcare Ltd, a subsidiary of the Springer Nature Group, was founded in 2022.
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