Private-Label Biosimilars Are Being Filled
Are private-label biosimilars actually being filled? Medicare Part D prescription drug events extend the formulary discussion from products listed for coverage to products with reported utilization.
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The short answer
Yes. PBM-affiliated private-label biosimilars were present in the Medicare Part D utilization data, including positive utilization for Cordavis Pyzchiva. But presence and scale are different questions. In the first seven months of 2026, private-label products still represented only a small share of total reported utilization for both adalimumab and subcutaneous ustekinumab.
Biosimilars overall had already become a majority of reported utilization in both markets. Private-label products, however, accounted for 1.53% of all adalimumab utilization and 1.70% of subcutaneous ustekinumab utilization. Among biosimilars alone, their shares were 2.46% and 3.23%, respectively.
2026 utilization shares
| Molecule | Biosimilar share of all utilization | Private-label share of all utilization | Private-label share of biosimilar utilization |
|---|---|---|---|
| Adalimumab | 62.3% | 1.53% | 2.46% |
| Ustekinumab, subcutaneous | 52.7% | 1.70% | 3.23% |
Source: FastHSR analysis of Medicare Part D prescription drug events. The 2026 period includes seven months.
Small shares, faster monthly utilization
Because the 2026 file contains seven months rather than a full calendar year, annual totals are not directly comparable. We compared average monthly private-label utilization in those seven months with the 2025 monthly average. Adalimumab increased 295.6%, while subcutaneous ustekinumab increased 96.9%.
| Molecule | 2025 monthly average index | 2026 monthly average index | Change |
|---|---|---|---|
| Adalimumab | 100.0 | 395.6 | +295.6% |
| Ustekinumab, subcutaneous | 100.0 | 196.9 | +96.9% |
The index sets each molecule's 2025 monthly average to 100. The 2026 monthly average uses the seven reported months.
PBM patterns are not uniform
Results varied substantially across PBM administrators. The three largest PBM groupings had different biosimilar adoption levels and different private-label shares within the biosimilar segment.
| PBM administrator | Adalimumab | Subcutaneous ustekinumab | ||
|---|---|---|---|---|
| Biosimilar share | Private-label share of biosimilars | Biosimilar share | Private-label share of biosimilars | |
| CVS Caremark | 52.9% | 8.18% | 35.5% | 2.77% |
| Express Scripts | 77.6% | 1.93% | 67.1% | 2.87% |
| OptumRx | 75.0% | 0.30% | 78.7% | 4.04% |
PBM categories identify pharmacy benefit administration and do not establish plan ownership.
Affiliated products can be concentrated within the affiliated PBM
The claims do not support a universal claim that PBMs avoid their own labels. Some private-label products were disproportionately concentrated within their affiliated PBM administrator. For example, 85.7% of reported 2026 utilization for Cordavis-labeled private-label adalimumab products appeared in the CVS Caremark category. For subcutaneous ustekinumab, 65.3% of Nuvaila Wezlana utilization appeared in the OptumRx category, and 58.2% of Quallent Pyzchiva utilization appeared in the Express Scripts category.
Cordavis Pyzchiva also had positive Part D utilization in the data. That observation is narrower than a formulary coverage finding: positive claims utilization does not establish broad coverage, preferred placement, or the mechanism that allowed an individual prescription to be filled.