Association of concurrent acid-suppression therapy with survival outcomes and adverse event incidence in oncology patients receiving erlotinib.

ABSTRACT

PURPOSE: Acid-suppression therapy is known to decrease the systemic exposure of erlotinib. The erlotinib prescribing information recommends staggering dosing with a histamine-2 receptor antagonist (H2RA) and avoiding concurrent use of a proton pump inhibitor (PPI). This retrospective analysis evaluated the frequency of concurrent acid-suppression therapy in oncology patients receiving erlotinib and its association with outcomes. METHODS: All patients prescribed erlotinib within UC San Diego Health System between February 26, 2011, and February 28, 2014, were assessed for eligibility, survival outcomes and adverse events. RESULTS: Of the 76 patients in the analysis, 24 were prescribed both a PPI and an H2RA with erlotinib therapy (31.6 %). The two patient groups, with (n = 24) and without PPI/H2RA (n = 52), were similar in clinical characteristics and erlotinib dose. One patient received an H2RA therapy alone and was excluded from the analysis; no one received PPI therapy alone. Patients receiving erlotinib alone had a longer median progression-free survival (PFS) compared to patients with concurrent PPI/H2RA therapy (11.0 months vs. 5.3 months; P = 0.029). Overall survival (OS) and incidence of rash and/or diarrhea did not correlate with use of acid-suppression therapy. CONCLUSION: Nearly one-third of patients received acid-suppression therapy. Patients treated with erlotinib and PPI/H2RA therapy had shorter PFS, but similar OS and adverse event profile compared to those who did not receive acid-suppression.