Enhertu delivers a Phase III win in first-line HER2-mutant lung cancer

The companies said the result represents the first successful Phase III trial of a HER2-directed treatment in the first-line lung-cancer setting. Because the data are topline only, the announcement establishes that the primary endpoint was met but does not yet show the median PFS, hazard ratio, response rates or mature survival outcomes.

Why a first-line result matters

Enhertu is already approved in more than 80 countries and regions for adults with unresectable or metastatic NSCLC whose tumors have activating HER2, also known as ERBB2, mutations and who have received prior systemic therapy. DESTINY-Lung04 evaluated the drug earlier in the treatment pathway, before that prior-treatment requirement.

A positive Phase III result could support regulatory discussions or applications seeking a first-line indication. It does not, however, change the approved label by itself; regulators will need to review the complete efficacy and safety dataset. The companies have said that overall survival and other secondary analyses will continue.

HER2 mutations are uncommon in NSCLC, affecting approximately 2% to 4% of patients according to Daiichi Sankyo’s trial announcement. That makes molecular testing especially relevant when clinicians are identifying potential treatment options for advanced non-squamous disease, although this announcement does not provide enough information to determine how testing practices or treatment guidelines will change.

What was reported about safety

AstraZeneca and Daiichi Sankyo said Enhertu’s safety profile was consistent with its established profile and that no new safety concerns were identified. The full safety dataset has not yet been published in the information provided, so the frequency and severity of adverse events in DESTINY-Lung04 cannot yet be independently assessed from the topline announcement.

The contrasting volrustomig decision

AstraZeneca also announced that it was discontinuing the Phase III eVOLVE-Lung02 trial, which tested volrustomig plus chemotherapy against pembrolizumab plus chemotherapy as first-line treatment for metastatic NSCLC with tumor PD-L1 expression below 50%.

The decision followed a planned review by the trial’s independent data-monitoring committee. The committee concluded that the volrustomig combination was unlikely to meet either of the study’s dual primary endpoints: PFS or overall survival.

This was a setback for the specific volrustomig combination and trial setting, not evidence that every volrustomig study had been terminated. AstraZeneca said other studies of the drug would continue.

The two announcements therefore offered a mixed picture of AstraZeneca’s lung-cancer pipeline: a potentially important targeted-therapy result in a biomarker-defined population, alongside the withdrawal of an immunotherapy combination that was unlikely to outperform the comparator in a broader metastatic NSCLC population.

What happens next

The next meaningful updates will be the detailed DESTINY-Lung04 data, including the magnitude of the PFS benefit, objective response results, duration of response, safety details and overall-survival follow-up. Until those data are available and regulators act, Enhertu’s reported success should be viewed as a strong clinical-trial result rather than a completed change to first-line treatment standards.

AstraZeneca’s shares rose in early trading after the group of lung-cancer announcements, with Investing.com reporting a move of about 1.6% to approximately 11,650 pence. Market reactions are short-term signals, however, and do not establish the eventual commercial or clinical impact of the trial.