For self-funded groups or groups that have carved out their pharmacy benefit, biosimilar adoption has become a practical test of PBM performance. The opportunity is real: biologics account for just 5% of prescriptions but 51% of drug spending, according to the FDA, and biosimilars generated $20.2 billion in U.S. savings in 2024 alone, according to the Association for Accessible Medicines.
But those savings don’t happen automatically. Biosimilar adoption is not just about placing a drug in a preferred formulary position. It depends on whether a PBM can move providers, patients, and pharmacies through the transition in a way that delivers sustained adoption, protects continuity of care, and creates lasting value for clients and their members.
Why Biosimilar Savings Do Not Happen Automatically
The biosimilar pipeline is expanding quickly. As of March 2026, the FDA had approved 82 biosimilars. But approval alone hasn’t translated into consistent adoption across the market. For drugs like adalimumab, uptake accelerated only after payers and PBMs changed formulary and contracting strategies.
That is where brokers advising clients through PBM selection or renewal need to look more closely. A PBM can say it supports biosimilars and offers cost savings through strict formulary controls. But the more important question is whether it can execute the transition in a way that protects continuity of care for members—and gives providers, patients, and pharmacies confidence in the change. That’s where projected savings either hold up or start to break down.
Even when the clinical case is strong, adoption can stall if providers are hesitant to change a patient that's stable on therapy, patients are unclear about what the switch means, or pharmacies are not prepared to manage it smoothly. A biosimilar strategy that lives only on paper tends to break down at the point of care. Providers push back. Patients get nervous. Pharmacies receive mixed signals. Members may revert to the reference product or switch to higher-cost biologics that do not have biosimilar alternatives. And projected savings never fully materialize.
What Makes Biosimilar Conversion Stick
A clinically disciplined PBM approaches biosimilar conversion as more than a formulary exercise. What makes conversion work is not the switch itself, but everything around it. The PBMs that see stronger results are usually the ones that treat it as a coordinated clinical effort by preparing pharmacies before the change takes effect, giving prescribers clear information, communicating early with patients, and monitoring closely to prevent avoidable disruption once the transition begins.
That’s where the difference shows up in practice. PharmPix doesn’t just recommend biosimilars as a lower-cost option. It’s shown an ability to move members to those therapies and sustain adoption over time. Across the PharmPix book of business, biosimilars targeted through clinical programs reached 60% to 90% market share in 2025. In one conversion effort, PharmPix reduced Humira use from more than 90% to under 15% in less than a year and achieved a 75% biosimilar transition success rate, with members remaining on the biosimilar for more than six months. In a separate Stelara initiative, 100% of members who transitioned to a biosimilar remained on that therapy after six months.
Real biosimilar value depends on whether a PBM can turn formulary intent into a transition that providers will support, patients will stay on, and pharmacies can carry out without friction.
What Brokers Should Look for in a PBM Biosimilar Strategy
The strongest PBM Biosimilar strategies tend to share four traits:
1. Clinically Led, Not Just Formulary Led
A stronger model doesn’t approach biosimilar conversion as a blanket cost-saving move. It evaluates where conversion is clinically appropriate, where communication needs to be more targeted, and where disruption risk needs to be managed more carefully.
2. Built to Support the Transition, Not Just Measure It
It has a technology backbone that supports action, not just reporting. The ability to identify eligible members, coordinate outreach, monitor the transition in real time, and respond quickly when issues arise is what turns a biosimilar strategy into measurable results.
3. Designed to Protect Disease Control During the Transition
Biosimilar adoption is not just about formulary controls. A successful strategy helps members move from the original biologic to the biosimilar through clear communication, careful coordination, and ongoing support so the transition doesn’t disrupt treatment. When that support is missing, the result is not just member confusion. It can also drive higher medical and pharmacy costs if patients stop therapy, need additional care, or end up on higher-cost alternatives.
4. Built Around the Full Prescription Journey
A biosimilar strategy must work across the full prescription life cycle, not just at the point of formulary change. Do providers understand what is changing and why? Are pharmacies stocked and prepared to support the transition? Will members maintain adherence after the switch? These are the questions that determine whether the strategy holds after conversion or begins to break down.
The Real PBM Differentiator in Biosimilar Adoption
For brokers, this is where the conversation gets real. Clients aren’t longer looking for theoretical savings. They’re looking for confidence that a biosimilar strategy will hold in a market where biologics continue to drive trend, biosimilar options are multiplying, and poor implementation can create as many problems as it solves. For self-funded groups, the stakes are even higher: if the transition is not handled well, savings can be missed entirely, disruption rises, and patient and provider confidence takes the hit.
Biosimilars are no longer the question mark. What matters now is whether plans can capture the full value they make possible. PharmPix's 75% biosimilar transition success rate shows that strong adoption is achievable. But adoption alone isn’t the finish line. The real opportunity lies in building the clinical discipline, provider engagement, patient support, and follow-through needed to make those results sustainable. That’s where clients either realize the savings or miss the opportunity.
FAQs
Why do health plans miss biosimilar savings opportunities?
Savings can be lost when a biosimilar transition is not supported by provider communication, member education, pharmacy readiness and ongoing follow-through.
How can employers and brokers evaluate a PBM’s biosimilar program?
Look for a clinically led program that identifies eligible members, coordinates with providers and pharmacies, supports members through the change and monitors adoption over time.
Are biosimilars appropriate for every patient?
No. A biosimilar transition should be evaluated based on clinical appropriateness, therapy history and the need to maintain continuity of care.
What makes biosimilar adoption successful?
Successful adoption depends on more than formulary placement. It requires a coordinated transition that providers support, members understand and pharmacies can carry out smoothly.
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