Biosimilar Hematology Roundup: December 2018

On the heels of the FDA approval of Celltrion’s rituximab biosimilarTruxima in November 2018, December saw the publication of a variety of new data on biosimilars used in hematology.

Much of those data were derived from this month’s American Society of Hematology’s 60th Annual Meeting & Exposition, held from the first to the fourth of the month in San Diego, California, during which several research teams presented fresh findings that underscore the benefits of biosimilars.

A number of those research teams focused on granulocyte colony-stimulating factor (G-CSF) therapies. First, assessing data from the Saskatchewan Cancer Agency, which switched to using Apotex’s filgrastim biosimilar, Grastofil, for stem cell mobilization prior to autologous stem cell transplants (ASCT) in 2016, researchers found that, when using either the biosimilar or the reference Neupogen before ASCT, each medication has similar efficacy. The authors concluded that prescribing the biosimilar over the reference product could provide substantial savings.

Another team found that, among patients undergoing transplantation who were receiving Zarxio or the reference filgrastim, there was no difference in plerixafor use between the 2 groups. Given that the cost of the biosimilar was approximately 50% lower than that of the reference product, using the biosimilar G-CSF agent once again provided an opportunity for significant cost savings.

Biosimilar filgrastim was shown to generate substantial cost savings over reference pegfilgrastim in its on-body injector presentation. In a simulation analysis from the payer perspective, researchers concluded that the incremental costs of delivering pegfilgrastim via on-body device for febrile neutropenia (FN) prophylaxis was lowest when compared with regular pegfilgrastim, and highest when compared with biosimilar filgrastim, at a real-world duration of 5 days.

A follow-on filgrastim, tbo-filgrastim (Granix) was demonstrated to provide the greatest cost-savings for the Veterans Health Administration, beating both Zarxio and the reference filgrastim on savings realized. However, switching patients to tbo-filgrastim from the brand-name option provided only a modest savings—just 2.2%—under 340B pricing. According to researchers, other approaches to reducing the cost of G-CSF therapy are likely to have a greater impact on the overall cost of care than a switch to biosimilars, including:

• Avoiding the use of G-CSF therapies in cases in which there is no convincing evidence of their efficacy
• Continuing to use short-acting agents instead of long-acting therapies
• Investigating the feasibility of using 2-day or 4-day courses of filgrastim rather than 8-day courses

Despite findings showing that biosimilars can curb costs, concerns remain about the slow pace of US biosimilar uptake for the prophylaxis of FN. Writing in JAMA Oncology, a team of authors pointed to the current lack of interchangeability, patent litigation, and rebates as culprits for low uptake. Writing in The Center for Biosimilars^®, contributor Isha Bangia, PharmD, MBA, highlighted the payer’s role in the sluggish pace of biosimilar adoption.

Among rituximab biosimilars, the newly approved Truxima was shown in several studies to be safe and effective in treating a variety of hematological diseases. First, UK researchers reported that the reference and biosimilar rituximab demonstrated equivalence in treating patients with immune thrombotic thrombocytopenic purpura, and that the mean savings to the healthcare system per patient treated with the biosimilar was £4000 (approximately $5089). Second, results from the first 7 months of a phase 3 study in patients with previously untreated follicular lymphoma (FL) with low tumor burden demonstrated that Truxima and the reference rituximab had therapeutic equivalence. Finally, a study in patients with previously untreated advanced FL showed that, at 23 months, treatment with Truxima or its reference led to comparable progression-free survival.

Additionally, PF-05280586, a proposed rituximab developed by Pfizer, got a boost from new data that showed that the efficacy, safety, immunogenicity, pharmacokinetics, and pharmacodynamics of PF-05280586 and the reference rituximab were similar at 26 weeks in patients with previously untreated CD20-positive FL with low tumor burden.

Industry appears to expect substantial sales from Pfizer’s product; Vantage’s annual preview of the pharmaceuticals market predicted that, in 2019, the proposed rituximab biosimilar for which a regulatory decision is expected in the third quarter of the year will be among the most valuable research and development projects of the year. The proposed biosimilar has a net present value of $3.6 billion, Vantage said.