Impact of carboplatin and cisplatin shortages on treatment patterns in patients with metastatic solid tumors.

person Emily Castellanos Flatiron Health, New York, NY info_outline Emily Castellanos, Qianyu Yuan, Niquelle Wadé, Khilna Patel, Catherine Rinaldi, Samantha Reiss, Eunice Hankinson, Aaron B. Cohen, Melissa Estevez

Authors person Emily Castellanos Flatiron Health, New York, NY info_outline Emily Castellanos, Qianyu Yuan, Niquelle Wadé, Khilna Patel, Catherine Rinaldi, Samantha Reiss, Eunice Hankinson, Aaron B. Cohen, Melissa Estevez Organizations Flatiron Health, New York, NY Abstract Disclosures Research Funding Flatiron Health Background: The United States experienced cisplatin (CP) and carboplatin (CB) shortages in 2023, leading to potential rationing or switching to alternative therapies in multiple cancers. Using a US nationwide, real-world oncology dataset, we assessed changes in the use of CP and CB in 7 cancers during the shortage period. Methods: All patients (pts) from the Flatiron Health electronic health record-derived de-identified database (~280 cancer clinics, ~800 sites of care) with a machine learning-extracted metastatic (met) diagnosis of a cancer of interest between March 2022 and June 2023 and evidence of first-line (1L) therapy, were selected. Pts with multiple primaries were excluded. Platinum of interest was identified based on frequency of pre-period 1L use for a given cancer. The pre-period was June 2022 through first month of reported shortage (February 2023 for CP; April 2023 for CB); data cutoff was June 2023. Clinical characteristics of platinum-treated pts stratified by pre- vs post-period by disease were assessed. 1L platinum utilization rates (UR), calculated as the proportion of 1L-treated pts initiating CB/CP within 30 days of met diagnosis, were plotted by month. Cohort-level impact was evaluated with an interrupted time series analysis—overall and stratified by practice type, practice size, and socioeconomic status (SES). Multiple testing was controlled using the Benjamini-Hochberg procedure. Results: 10,983 pts received 1L therapy in the study period. Monthly platinum UR were stable across diseases in the pre-period. However, there was a significant post-period decrease in CB usage for non-small cell lung (NSCLC) and endometrial cancers (EC), and a decreasing trend in UR for CB in bladder (BC), ovarian (OC), and small cell lung cancers (SCLC). We also observed a decreasing trend in CP usage for cholangiocarcinoma (CC). Post-period monthly UR were stable for CB and CP in head and neck cancer (HNC), and for CP in BC. Odds ratios (OR) representing the month-over-month change in the odds of receiving platinum therapy during both pre- and post-periods are shown (table). OR trends varied by practice type and disease; no notable trends were seen by practice size or SES. UR with additional follow-up times will be presented. Conclusions: We observed decreased platinum use across multiple cancers during the shortage period, most notably for met NSCLC and EC, suggesting shortages led oncologists to seek alternatives to standard 1L platinum-based regimens. Further study of how treatment changes due to platinum shortages impacted pt outcomes is warranted. Platinum N (pre) N (post) OR (pre) OR (post) P value BC CP 277 217 1.13 0.97 0.32 BC CB 360 134 0.99 1.04 0.90 HNC CP 426 306 1.01 0.96 0.56 HNC CB 533 199 0.99 0.74 0.17 OC CB 657 194 1.01 0.73 0.08 EC CB 495 164 1.06 0.58 0.004* NSCLC CB 5272 1560 1.00 0.71 <0.001* SCLC CB 699 183 1.02 0.80 0.20 CC CP 310 223 0.98 0.83 0.16 *significant after multiple testing adjustment.