Cancer Immunotherapy Stewardship - Cost-Neutral, Patient-Centered Dosing to Increase Infusion Center Efficiency.

Abstract

At a Veterans Affairs medical center, an immunotherapy stewardship initiative was developed to optimize dosing of pembrolizumab, which accounted for Medicare Part B's largest single line item for total spending, at more than US$5.4 billion in 2023. Pembrolizumab received regulatory approval in 2014 at a personalized dose of 2 mg/kg every 3 weeks; however, in the United States, practice is now dominated by fixed 200 mg every-3-weeks dosing (approved in 2017) and 400 mg every-6-weeks dosing (approved in 2020), with all patients dosed on the assumption that they weigh 100 kg. This status quo very likely results in unnecessary drug use, excessive spending, and lost opportunities to improve patient experience. The authors developed a stewardship initiative around a 4 mg/kg every-6-weeks dosing option, now recommended in many contemporary oncology guidelines, which is more time-efficient for infusion centers and practices, more cost-effective for payers, more convenient for patients, and is supported by a strong pharmacologic rationale and international precedent. The stewardship initiative, which ran from July 1, 2024, through June 30, 2025, introduced dose banding, new electronic medical record (EMR) order sets, and pharmacist-led education to guide prescribers toward utilization of the more cost- and time-efficient dosing option. Quarterly audit feedback reinforced adoption. Evaluation included prescribing trends, drug utilization, and cost and patient time savings. Over the 12-month intervention, the every-6-weeks dosing option for pembrolizumab monotherapy increased from about 60% (among 25 unique patients in month 1) to 80% (among 34 unique patients per month in month 12), while the pembrolizumab administered as part of a combination regimen with intravenously administered chemotherapy (i.e., combination therapy) remained predominantly every 3 weeks owing to EMR and cultural barriers. Compared with counterfactual estimates, the program was associated with approximately US$296,000 in averted drug costs (about 6.5% of an expected US$4.55 million spend), capturing more than 90% of modeled potential savings. Time savings were notable: With a median infusion encounter lasting nearly 180 minutes, every-6-weeks dosing helped avert more than 450 hours of health care contact time, which is equivalent to approximately 6 hours saved per recipient over the course of 1 year. Limitations include some marginal uptake of every-6-weeks dosing, which most likely would have occurred even without the intervention, the financial analysis focusing solely on drug acquisition costs and not accounting for potential cost savings related to fewer infusions, and the lack of consideration of adjacent provider and health system efficiency gains. Nevertheless, the initiative demonstrates that pragmatic tools - dose banding, EMR redesign, pharmacist involvement, and feedback loops - can meaningfully improve the time- and cost-efficiency and patient experience without increasing drug-related spending. Stewardship offers a replicable framework for health systems to balance value, efficiency, and patient-centered care in oncology.