A phase 2 trial of trastuzumab deruxtecan in patients with non-small-cell lung cancer demonstrated a median overall survival of 17.8 months.
Lung cancer is extremely common and figures from 2018, suggest a global incidence of 17 million cases and 9.6 million associated deaths. Primary lung cancers can be either small cell or non-small cell, with the latter being the most common, accounting for around 80 to 85% of all lung cancer cases. Research has identified the presence of various genetic mutations in lung cancer, one of which is a mutation in the human epidermal growth factor 2 (HER2). This mutation is present in roughly 2 to 4% of non-small cell lung cancer (NSCLC) cases. Given the over-expression of HER2, potential treatments include the anti-HER2 agent, trastuzumab, but when used in combination with chemotherapy, there was a lack of benefit. The antibody-drug conjugate, trastuzumab deruxtecan, has been shown to be effective in both HER2 positive gastric and breast cancers but data on its efficacy in NSCLCL is limited to a single phase 1 trial in 11 patients, which showed an objective response rate in 72.7% (8/11) of patients.
Based on these preliminary findings, an international team, the DESTINY-Lung01 trial investigators, conducted a multi-centre, phase 2 trial of trastuzumab deruxtecan given at a dose of 6.4 mg/kg body weight, to patients with metastatic HER2-mutant NSCLC that was refractory to standard treatment. Eligible patients had unresectable or metastatic non-squamous NSCLC with at least one measurable lesion as defined according to the Response Evaluation Criteria in Solid Tumours (RECIST), which provides a simple and pragmatic methodology to evaluate the activity and efficacy of a new anti-cancer therapy in solid tumours. The primary end point was confirmed objective response, independently assessed on the basis of RECIST. Secondary endpoints included the duration of response, disease control and progression-free survival and overall survival. The study also examined the safety of treatment.
A total of 91 patients with a median age of 60 years (66% female) were enrolled in the study and who had a median of 2 previous cancer therapies. There were 50 (55%) patients who achieved a confirmed objective response, with one patient having a complete response and just over half (54%) having a partial response. In addition, the majority (91%) of patients had disease control and a reduction in tumour size. The median progression-free survival time was 8.2 months and the median overall survival, 17.8 months. In terms of safety, 51% of patients experienced a grade 1 – 2 adverse event and grade 3 or higher drug-related adverse events occurred in 41% of patients. The most common adverse effects were nausea (64%) and fatigue (46%) although these were mainly of grade 1 – 2 severity.
The authors concluded that the use of trastuzumab deruxtecan had shown a response in a high number of patients and durable clinical benefit and that a further randomised trial to further evaluate the drug conjugate is underway.
Li BT et al. Trastuzumab Deruxtecan in HER2-Mutant Non–Small-Cell Lung Cancer. N Eng J Med 2021.