Conflict of interest

Laura A. Huppert, Zak Walker, Moming Li, Mi-Ok Kim and Melanie Majure: no financial disclosures. Jennifer Callan: none relevant to this work. Employed by Arcus Biosciences, an oncology-focused biopharmaceutical company. Danielle Brandman: none relevant to this work. Research funding from Gilead, Genentech, Allergan, Conatus, Grifols. Michelle E. Melisko: research funding to institution: Astra Zeneca, Novartis, KCRN Research, Puma, Seattle Genetics. For spouse: Speaker bureau/honoraria: Genentech, Gilead, Astra Zeneca. Stock Ownership: Merrimac. Hope S. Rugo: research support for clinical trials through the University of California: Pfizer, Merck, Novartis, Lilly, Roche, Daiichi, Seattle Genetics, Macrogenics, Sermonix, Boehringer Ingelheim, AstraZeneca, Astellas and Gilead. Honoraria from: Puma, Samsung, Mylan, Chugai, Blueprint, and NAPO. Spencer Behr: none relevant to this work. Scientific Advisory Committee member for Navidea and Consultant for GenVivo. Jo Chien: research funding to institution: Merck, Puma, Amgen, Seagen.

Ethics approval

This research was approved by the UCSF Institutional Review Board.

Consent to participate and publish

Patient consent was not required given that this was a retrospective, observational study approved by the UCSF Institutional Review Board.