Concomitant use of capecitabine and proton pump inhibitors - Is it safe?

BACKGROUND: Capecitabine is a commonly used oral chemotherapy agent. Recent data suggest that concurrent use of proton pump inhibitors may reduce the efficacy of capecitabine by decreasing its absorption through increased gastric pH. Since proton pump inhibitors are widely used, we evaluated the supportive evidence for the probability of occurrence and potential seriousness of this drug interaction. METHODS: The probability of occurrence was evaluated based on the clinical, pharmacokinetic and in vitro evidence using the Drug Interaction Probability Scale. The possibility of seriousness was assessed based on the potential impact on the therapeutic intent of capecitabine therapy. RESULTS: The probability of occurrence of the interaction is doubtful. Clinical findings from two retrospective post hoc analyses showed inconsistent trends towards reduced survival. Pharmacokinetics studies found no significant decrease in systemic capecitabine level with concurrent gastric acid suppression with antacid or food intake. In vitro data do not support the proposed mechanism of reduced capecitabine absorption due to increased gastric pH. The possibility of seriousness varies depending on the treatment intent of capecitabine therapy. The most and least serious possible outcome would be reduced possibility of cure or survival and symptom control, respectively. CONCLUSION: Although the possible outcome may be serious, the probability of interaction between capecitabine and proton pump inhibitors is doubtful. Therefore, we suggest that intervention should be limited to minimal change to existing therapy plan. This may include routinely ascertaining the need for proton pump inhibitor use. Alternate acid suppressing agents may be considered based on the therapeutic intent of capecitabine therapy.

Evaluation of the role of pharmacy technicians in reviewing the eligibility for Oncotype DX genomic test and the impact of the test on treatment plans in breast cancer patients.

PURPOSE/OBJECTIVES: The Oncotype DX genomic test is a treatment decision-making tool. Test results are presented as recurrence scores which are used to help decide between adjuvant hormonal therapy (low recurrence score) or chemotherapy (high recurrence score). Since 2014, the Oncotype DX test has been funded at the cancer treatment centres in our province for patients with early breast cancer. Eligibility criteria for funding include patient and tumour characteristics. Pharmacy technicians were assigned to review and approve requests based on the eligibility criteria and with access to consultation to an oncology pharmacist and a medical oncologist. We assessed the clinical role of pharmacy technicians in this review process and the impact of recurrence score on treatment decisions. METHODS: This was a retrospective, multi-centre study to evaluate the Oncotype DX test eligibility review process from June 2014 to May 2015. The main objectives were to assess (1) the discrepancy rate of approval by the pharmacy technicians in this review process and (2) the concordance rate between the recurrence score from the Oncotype DX test and the adjuvant treatment given. RESULTS: Four hundred and forty requests for Oncotype DX test were received during the study period. A total of 90.8% of requests were approved and 9.2% were denied. The discrepancy rate of approval by pharmacy technicians was 1.1%. The average review time was 13.8 min, with the reviewing pharmacist and oncologist consulted in 5.5 and 15.2% of the requests, respectively. The concordance rate between the recurrence score and given treatment was 96%. DISCUSSION: The discrepancy rate of our pharmacy technicians appears to be similar to that reported with other expanded technician roles in literature, suggesting that the current task and other similar clinical tasks can be reliably delegated to technicians. The concordance rate of the recurrence score and given treatment in our study was higher than what has been reported in literature, suggesting that most of our patients were treated in accordance to recurrence score-based recommendations. CONCLUSION: Pharmacy technicians were able to expand their clinical role by accurately reviewing the Oncotype DX test requests with a low discrepancy rate. The Oncotype DX test results appeared to successfully guide the adjuvant treatment given to patients in accordance to recurrence score-based recommendations.