Low rates of primary medication nonadherence in patients prescribed oral oncology agents across health system specialty pharmacies.

BACKGROUND: New oral oncology medications bring novel challenges when patients are initiating treatment. Rates of primary medication nonadherence (PMN), the rate at which a medication is prescribed but not obtained, of up to 30% have been reported for oral oncology medications. More research is needed to identify causes and develop strategies for health system specialty pharmacies (HSSPs) to improve cancer treatment initiation rates. OBJECTIVE: To evaluate the rate and reasons for PMN to specialty oral oncology medications in an HSSP setting. METHODS: We performed a multisite retrospective cohort study across 7 HSSP sites. Patients were included if they had an orally self-administered oncology medication referral generated by the health system of the affiliated specialty pharmacy between May 1, 2020, and July 31, 2020. Data collected at each site using pharmacy software and the electronic health record were deidentified and aggregated for analysis. After identifying unfilled referrals within a 60-day fill window, a retrospective chart review was performed to identify final referral outcomes and reasons for unfilled referrals. Referral outcomes were categorized as unknown fill outcomes (because of being referred to another fulfillment method or if received for benefits investigation only), filled by the HSSP, or not filled. The primary outcome was PMN for each PMN-eligible referral and secondary outcomes included reason for PMN and time to fill. The final PMN rate was calculated by dividing the number of unfilled referrals by total referrals with a known fill outcome. RESULTS: Of 3,891 referrals, 947 were PMN eligible, representing patients with a median age of 65 years (interquartile range = 55-73), near equal distribution between male and female (53% vs 47%), and most commonly with Medicare pharmacy coverage (48%). The most referred medication was capecitabine (14%), and the most common diagnosis was prostate cancer (14%). Among PMN-eligible referrals, 346 (37%) had an unknown fill outcome. Of the 601 referrals with known fill outcome, 69 referrals were true instances of PMN, yielding the final PMN rate of 11%. Most referrals were filled by the HSSP (56%). Patient decision was the most common reason for not filling (25%; 17/69 PMN cases). The median time to fill after initial referral was 5 days (interquartile range = 2-10). CONCLUSIONS: HSSPs have a high percentage of patient initiation of new oral oncology medication treatments in a timely manner. More research is needed to understand patient reasons for deciding not to start therapy and to improve patient-centered cancer treatment planning decisions. DISCLOSURES: Dr Crumb was a planning committee member with Horizon CME for the Nashville APPOS 2022 Conference. Dr Patel received funding and support for attending meetings and/or travel from the University of Illinois Chicago College of Pharmacy.

Potential cross-reactivity of polysorbate 80 and cremophor: A case report.

INTRODUCTION: Anaphylactic and hypersensitivity reactions are known adverse effects of many drug products and may be due to the inactive ingredients of the drug formulation. Specifically for paclitaxel and docetaxel, it is their excipients (cremophor and polysorbate 80, respectively) that have been identified as being most likely responsible for these reactions. CASE REPORT: The patient is a 39-year-old female, with a history of breast cancer and no known allergies, who was scheduled to start chemotherapy. While being administered fosaprepitant, she reported shortness of breath and was noted to be hypotensive and flushed. Two months later, the patient returned to clinic to start weekly paclitaxel. During the administration of the paclitxel test dose, the patient reported difficulty breathing, flushing, and chest tightness. Management and outcome: Both medication reactions were managed with epinephrine and other supportive medications. Fosaprepitant was taken out of the patient's antiemetic regimen for future cycles and paclitaxel was switched to nab-paclitaxel. DISCUSSION: It is well documented that paclitaxel and fosaprepitant have the potential to cause hypersensitivity reactions due to their excipients. While it is likely that each reaction was a unique event, it is difficult to ignore the possibility of cross-reactivity due to the presence of oleic acid in both excipients.