Questions to explore
The efficacy of patritumab deruxtecan was “high” in this phase 1 study, based on the reported response rate and median PFS, said discussant Nicolas Girard, MD, PhD, of Institut Curie in Paris.
However, the most striking finding of the study was the efficacy of the antibody-drug conjugate across all reported resistance mechanisms, Dr. Girard said in his remarks.
Questions that remains to be explored, according to Dr. Girard, include the impact of previous treatment sequencing with TKIs and chemotherapy on patient outcomes with patritumab deruxtecan, as well as the assessment of intracranial response and PFS for patients treated with the agent.
In addition, antitumor activity was seen across a wide range of baseline HER3 expression levels in this study, suggesting that a predictive biomarker remains to be identified, according to Dr. Girard.
“HER3 immunohistochemistry does not seem to be the candidate in this setting,” he said.
The study was sponsored by Daiichi Sankyo. Dr. Jänne reported disclosures related to Daiichi Sankyo, as well as Araxes Pharma, Astellas Pharma, AstraZeneca, and multiple other pharmaceutical companies. Dr. Jänne is also coinventor on a Dana Farber Cancer Institute–owned patent on EGFR mutations licensed to Labcorp and receives postmarketing royalties from this invention.
Dr. Girard reported disclosures related to AbbVie, AstraZeneca, Boehringer Ingelheim, and multiple other pharmaceutical companies.