A poster at the ASCO Quality Care Symposium describes how a value-based care partnership used prior authorization data and pharmacist workflows to move eligible patients off flat dosing of pembrolizumab.
Pembrolizumab (Keytruda; Merck) is the largest drug line-item in nearly every oncology practice’s budget. The PD-1 inhibitor is also one of the most important therapies ever seen in cancer care, with 44 indications across 19 different cancer types.1 Robert “Bobby” Green, MD, MSCE, president and chief medical officer of Thyme Care, says those 2 facts aren’t in conflict.
“It’s a great drug, right? Just to be clear,” Green said in an interview with The American Journal of Managed Care® (AJMC®). “I’m an oncologist. I saw people who would have died be cured by Keytruda.”
But if there’s a way to reduce a big line item, it makes sense for an oncology practice to do that if it’s safe for patients, especially if the practice might help patients save money, too.
Enter weight-based dosing, a concept that Green and a colleague outlined more than 2 years ago in Evidence-Based Oncology (EBO).2 It’s one that’s worked for Texas Oncology, the largest community oncology practice in the United States.
“This is not [that] we want to limit the use of Keytruda,” Green explained. “But here is a clinically appropriate cost-saving mechanism that you can deploy that can take the highest-cost anticancer drug and reduce the spend of it appreciably.”
At the recent American Society of Clinical Oncology Quality Care Symposium (ASCO Quality) in Boston, Massachusetts, Thyme Care shared results showing how this initiative reduced utilization and cut care costs by $723,000.3That translated into a 7.3% reduction compared with projected spending under flat dosing.3
Pembrolizumab is commonly given as a flat 200 mg every 3 weeks or 400 mg every 6 weeks. In their 2024 essay in EBO, Green and Samyukta Mullangi, MD, MBA, wrote, that approach “assumes that the average patient weighs 100 kg.”² Weight-based dosing gives smaller patients less drug and wastes less, without sacrificing efficacy.
Data collected during CMS’ Oncology Care Model (OCM), which ran from 2016 through 2022, showed that by the end of 2021, drugs made up more than 71% of total cost of care in a 6-month cancer episode in OCM.²
Texas Oncology had already adopted weight-based pembrolizumab dosing within the OCM successor model, the Enhancing Oncology Model. Then they partnered with Thyme Care, a value-based care enabler that takes on total cost-of-care risk through its health plan contracts. Through this initiative, Thyme Care and Texas Oncology worked together to extend the intervention to a shared Medicare Advantage population, which Green explained included approximately 4500 Texas Oncology patients who were also covered by plans that contract with Thyme Care. Under this construct, Thyme Care shares savings generated in that population with the practice—a key element of its value-based care offering.
According to the poster, patients weighing 80 kg or less were eligible. Those weighing 50 kg or less received 200 mg every 6 weeks, and those weighing 50.1 to 80 kg received 300 mg every 6 weeks.3
Green said community practices are well-suited to this work. “Community oncology practices, like Texas Oncology and others, are where a lot of innovation happens,” he said. “Physician-owned, physician-controlled entities are able to say, ‘This is important to us. We want to do this,’ whether it’s independently or with a partner.”
He added that the financial model is what makes the effort worthwhile. “It honestly doesn’t make sense to go through all of the operational work and time and energy to do this … in other settings,” he said. “But if you set up the right value-based programs to do it, … then you can actually make it make sense from an operational and from a financial standpoint.”
Of 613 pembrolizumab administrations analyzed across cancer types, 338 (55%) were eligible by weight. Of those, 115 (34%) were switched to weight-based dosing. That avoided the use of 11,800 mg of the drug.3
Monthly adherence ran between 28% and 36% from September 2025 through February 2026. It then rose to 48% in March and 46% in April.3 Green credited 2 changes for the jump:
“One of the things … that we underappreciate is the role of pharmacists in oncology practices and what a critical role they play,” Green said.
The poster’s authors also described working through “blockers.” The main one involved patients already partway through treatment. Patients starting cycle 1, day 1, are easy to flag from PA data. But it is also clinically appropriate to switch a patient on their eighth or 12th cycle. The team built an algorithm to identify those patients and send them to pharmacists for review.
The program is ongoing. “Our adherence is in the 60% range, which honestly, for an intervention like this, is sort of where we would expect it,” Green said.
Green described the 2 approaches as clinically equivalent, with weight-based dosing less expensive. For some patients, he said, lower drug spending also means lower out-of-pocket costs, which reduces financial toxicity.
Green said Thyme Care looks for interventions that are right for patients first, then weighs how much each would affect total cost of care. He pointed to several possibilities:
“There is a lot of alignment between high-quality care and less [use] of drugs, or less administrations of drugs, or a different dose of drugs,” Green said. “There are a lot of things that you can do within value-based care, and it’s a question of how do you align incentives, and how do you figure out how to operationalize them?”
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