AstraZeneca (AZN) and Daiichi Sankyo are facing a significant obstacle in their push to expand the use of cancer drug Enhertu into a key new treatment setting.
The two pharmaceutical giants have been working to establish Enhertu as a first-line therapy for patients with HER2-mutant non-small cell lung cancer, one of the most common forms of the disease.
However, preliminary data from a phase 3 clinical trial has revealed a 15% higher death risk among patients receiving the treatment in that setting.
The finding threatens to seriously derail the companies’ ambitions to broaden Enhertu’s approved uses and capture a significant share of the lucrative lung cancer treatment market.
Enhertu, known scientifically as trastuzumab deruxtecan, is an antibody-drug conjugate, a class of medicines that has attracted enormous attention and investment across the oncology sector in recent years.
The drug has already won regulatory approval for use in certain breast cancer and gastric cancer patients, where it has demonstrated strong efficacy and helped cement its reputation as a standout therapy.
AstraZeneca and Daiichi Sankyo have jointly developed and commercialised Enhertu through a high-profile collaboration deal that has been closely watched by investors and industry analysts.
Non-small cell lung cancer accounts for the vast majority of all lung cancer diagnoses, making it a particularly important and competitive commercial target for oncology drug developers.
HER2 mutations represent a distinct molecular subgroup within that patient population, and targeted therapies addressing such mutations have become an increasingly active area of clinical development.
A phase 3 trial is the most advanced stage of clinical testing before regulatory submission, making any negative signal at this point particularly consequential for the drug’s development programme.
The 15% elevated death risk identified in the preliminary data will now draw intense scrutiny from regulators, clinicians, and investors monitoring the programme’s progress.
Both AstraZeneca and Daiichi Sankyo will need to carefully analyse the full dataset to determine whether the trial results can be addressed or whether the first-line lung cancer strategy requires a significant rethink.