4. Rituxan

Roche said Rituxan continued to grow in the U.S. last year because prices and volume both increased. (Roche)

4. Rituxan
2018 U.S. sales: $4.24 billion
Used for: non-Hodgkin lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis, microscopic polyangiitis and pemphigus vulgaris

Roche’s Rituxan enjoyed another strong year in U.S. sales in 2018, but a cliff is approaching as biosimilars nip at the multitasking blockbuster’s heels.

Rituxan secured $4.24 billion in U.S. sales last year across its immunology and oncology uses, an increase of 4% from the year before. Roche said the drug continued to grow because both prices and volume increased in the U.S., maintaining its hold as the company's highest-performing stateside and third-best-selling drug worldwide.

Although Rituxan enjoys its place as tops among Roche’s trifecta of top-performing cancer drugs—alongside Avastin and Herceptin—the drug is under threat now that Celltrion and Teva’s biosimilar, Truxima, has won its FDA approval and is preparing for a launch later this year. 

While Truxima has yet to hit the market, early figures in Europe could indicate Rituxan’s upcoming troubles. In the third quarter of 2018, Rituxan sales dropped 49% in the EU, underscoring the challenge Roche faces stateside. However, history says biosimilar penetration could be far slower in the U.S., with discounts closer to 15%.

Fortunately, at least one of Rituxan’s competitors is off the table, though. Novartis’ Sandoz unit pulled its biosimilar challenger after the FDA rejected its application in November.

4. Rituxan