The Impact of Dose and Simultaneous Use of Acid-Reducing Agents on the Effectiveness of Vemurafenib in Metastatic BRAF V600 Mutated Melanoma: a Retrospective Cohort Study

The concomitant use of proton pump inhibitors and BRAF/MEK inhibitors in metastatic melanoma

BACKGROUND

Proton-pump inhibitors (PPIs) are commonly used by patients with cancer, although they could reduce the absorption of oral anticancer targeted therapies. The US Food and Drug Administration states that the effect of PPIs on the efficacy of dabrafenib use by patients with metastatic melanoma is unknown. As a precautionary measure, the European Society for Medical Oncology recommends avoiding PPIs for patients receiving dabrafenib.

OBJECTIVES

To determine the effect of the concomitant use of PPIs and BRAF/MEK inhibitors in patients with metastatic melanoma.

METHODS

Patients with advanced melanoma receiving BRAF/MEK inhibitors as first-line treatments between 2015 and 2017 in France were selected using the French National Health Insurance database. We compared time-to-treatment discontinuation (TTD) and overall survival (OS) according to concomitant PPI exposure. We balanced the baseline characteristics of patients exposed and nonexposed to PPIs using an overlap weighting method based on a propensity score.

RESULTS

The metastatic melanoma cohort comprised 1028 patients receiving BRAF/MEK inhibitors, including 361 (35.1%) patients using PPIs. PPI users had more comorbidities and a more severe metastatic disease. After having equally distributed metastatic sites and comorbidities across patients exposed and nonexposed to PPIs, concomitant PPI use was not associated with shorter TTD [weighted hazard ratio (wHR) 1.03, 95% confidence interval (CI) 0.86-1.24] or OS (wHR 1.11, 95% CI 0.88-1.39). Consistent results were observed when restricting the population to patients receiving dabrafenib, or when narrowing exposure to PPIs with stronger inhibition of cytochromes.

CONCLUSIONS

In a population-based cohort of patients with advanced melanoma, the concomitant use of PPIs and BRAF/MEK inhibitors was not associated with worse outcome.

Controversial link between proton pump inhibitors and anticancer agents: review of the literature

Drug-drug interactions represent a topic of great interest, not only due to the risk of unexpected adverse events but also due to the possibility of altering the effectiveness of a specific treatment. Inappropriate or concomitant use of drugs can often lead to changes in the bioavailability of various compounds, resulting in pharmacokinetic alterations. A recent example is the concomitant administration of proton pump inhibitors (PPIs) and anticancer agents. PPIs are overused beyond their classic indications, resulting in a high risk of interactions with other drugs, such as anticancer agents, both PO and intravenous. However, the real clinical impact of concomitant acid suppression therapy and anticancer therapies remains controversial and is not yet fully understood. Certainly, the gut microbiota plays a key role in regulating the response of the immune system, and PPIs can significantly alter the gut microbiome, resulting in gut dysbiosis. Indeed, while the link sometimes appears to lead to negative outcomes, as in the case of immunotherapy, oral capecitabine, or tyrosine kinase inhibitors, in other cases, it seems to enhance the effectiveness of intravenous chemotherapy. In this review, I analyse the possible drug interactions between PPIs and the main classes of anticancer drugs.

Proton Pump Inhibitors and Oncologic Treatment Efficacy: A Practical Review of the Literature for Oncologists

Proton pump inhibitors (PPIs) are the most commonly used anti-acid drugs worldwide, including among cancer patients. However, drug-drug interactions between PPIs and other agents may lead to decreased drug absorption with possible reduced therapeutic benefit, or even increased toxicity. Unfortunately, only scarce data exist regarding the safety of concomitant PPI use with anti-cancer agents. We aim at reviewing current evidence on this possible interaction by dividing anti-cancer agents by class. Until further data is available, we encourage healthcare providers to limit unnecessary PPI overuse.

Effect of concomitant dosing with acid-reducing agents and vemurafenib dose on survival in patients with BRAFV600 mutation-positive metastatic melanoma treated with vemurafenib ± cobimetinib

BACKGROUND

We conducted a retrospective analysis to evaluate the impact of concomitant acid-reducing agents (ARAs) and vemurafenib dose on the efficacy of vemurafenib in patients with BRAFV600 mutation-positive unresectable or metastatic melanoma treated with vemurafenib or cobimetinib plus vemurafenib.

METHODS

Data were pooled for patients treated with vemurafenib or cobimetinib plus vemurafenib in the BRIM-2, BRIM-3, BRIM-7, and coBRIM studies. The primary end-points were progression-free survival and overall survival across patient subgroups defined by vemurafenib dose (full vs reduced) and concomitant ARA use (yes vs no). Objective response rate (ORR) was also analysed. Steady-state vemurafenib concentrations were evaluated according to vemurafenib dosing and concomitant ARA use across treatment cohorts in a subset of patients from BRIM-7 and coBRIM with available concentration data.

RESULTS

Efficacy analyses included 920 patients: 641 in the vemurafenib cohort and 279 in the cobimetinib plus vemurafenib cohort. Overall, no significant differences in survival outcomes were observed across subgroups according to vemurafenib dose and ARA use, with or without adjustment for known prognostic covariates, in both treatment cohorts. ORR was also similar across subgroups in both treatment cohorts. Steady-state vemurafenib concentrations were analysed in 389 patients (193 in the vemurafenib cohort and 196 in the cobimetinib plus vemurafenib cohort) and were generally similar across vemurafenib dose subgroups, regardless of ARA use in both treatment cohorts.

CONCLUSIONS

Results of this retrospective pooled analysis suggest that ARAs can be used concomitantly with vemurafenib, alone or in combination with cobimetinib, without compromising the efficacy of vemurafenib.