After 8 years of trastuzumab biosimilar competition and slow uptake, a new report shows that trastuzumab biosimilar discounts from the reference product (Herceptin) doubled between 2019 and 2022.
Researchers found that discounts for trastuzumab biosimilars have doubled in the last few years, showing that increased competition on the US market is resulting in lowering prices despite a slow growth for the biosimilar industry.
The report, published by the University of Southern California (USC) Leonard D. Schaeffer Center for Health Policy & Economics in Health Affairs, analyzed pricing trends for Herceptin (reference trastuzumab) and its 5 biosimilar competitors (Kanjinti, Ogivri, Ontruzant, Herzuma, and Trazimera), the first of which launched in July 2019 (Kanjinti) and the last launched in April 2020 (Ontruzant). The study is one of the first to look at multiple biosimilar competitors in terms of US market share, price, and prescribing habits.
Trastuzumab products are used to treat HER2-positive breast, stomach, and gastroesophageal junction cancer. Herceptin was approved by the FDA in September 1998. Since the introduction of biosimilars on the US market, biosimilars have faced several challenges to entering the market and obtaining market share, including patent thickets, delayed entrance dates, lack of education and trust among patients and providers, access issues due to payers not placing them on formularies, and provider prescribing incentives (rebates and reimbursement) prioritizing reference products.
“Trastuzumab is the best example to date of biosimilars fulfilling their promise to reduce biologic drug prices…. In just 3 years, the trastuzumab market displayed important hallmarks of competition: doctors could choose among 6 products; new entrants rapidly captured market share from the originator; and prices steadily declined on all 6 options,” Alice Chen, PhD, coauthor of the study, an associate professor and vice dean for research at the USC Sol Price School of Public Policy, and senior fellow at the USC Schaeffer Center, said in a statement.
By the second quarter of 2022, the average sales prices for trastuzumab biosimilars ranged from 28% to 58% lower than Herceptin’s, a significant increase from the first quarter of 2019, which ranged from 15% to 46% lower than Herceptin’s precompetition net price.
Additionally, the Herceptin’s average sales price fell 21% from $101 to $80 per 10 mg as a result of biosimilar competition.
Kanjinti was found to have the “first-mover advantage” over the other trastuzumab biosimilars by having the highest market share in most states. Hospital-based physicians prescribing trastuzumab tended to prescribe either the reference product or a biosimilar, but not both. However, office-based physicians were more likely to prescribe the reference product and biosimilars more evenly.
“Our analysis applies to a physician-administered drug under Medicare Part B, and provides the best evidence so far that biosimilars can reduce originator drug prices quickly, in the same way that generics reduce prices of small-molecule drugs…. Our findings support the growing body of evidence that biosimilars do in fact reduce biologic drug prices in the physician-administered market. Whether they can do the same in the retail drug market remains to be seen, as the industry brings more of these products to the market,” said coauthor Karen Van Nuys, PhD, executive director of the Value of Life Sciences Innovation program and a senior fellow at the USC Schaeffer Center.