AMCP Posters Highlight Clinical, Real-world Application of Trastuzumab, Infliximab Biosimilars

Posters from the Academy of Managed Care Pharmacy’s annual meeting highlighted the clinical similarity of a trastuzumab biosimilar compared with its reference product (Herceptin) and real-world longitudinal application of 4 infliximab biosimilars.

Real-world Switching and Discontinuation of Infliximab Biosimilars¹

Investigators from the Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) conducted a scoping review of observational studies that have examined real-world evidence on the switching and discontinuation patterns of infliximab biosimilars in patients with rheumatoid arthritis (RA).

RA affects about 1.28 million to 1.38 million adults in the United States. There are currently 4 infliximab biosimilars approved for the treatment of RA in the United States and European Union: Avsola (infliximab-axxq), Renflexis (infliximab-abda), Ixifi (infliximab-qbtx), and Inflectra (infliximab-dyyb).

Current published literature contains limited large-scale comparative observational studies describing real-world patterns of use of infliximab biosimilars compared with the reference product (Remicade). Fewer studies have been conducted that have compared these patterns between biosimilars.

The investigators conducted a literature search in 3 databases for studies published between 2015 and 2020, with the latest search occurring on February 18, 2021. For inclusion, the studies had to be published in English, be observational studies, and examine the switching and/or the discontinuation of infliximab products in adult patients with RA. Of the 1130 studies identified, 18 were included in the review.

The studies were conducted in Denmark, Portugal, the Republic of Korea, Bulgaria, the Czech Republic, Romania, the Netherlands, Finland, France, Canada, the United States, Turkey, and Spain, with some studies including data from multiple countries and some countries included in multiple studies.

Many of the outcomes from the studies were pooled for a combination of inflammatory diseases and about one-third of them had a biosimilars sample size of 50 patients or less. Among the 18 studies, 12 listed reasons for discontinuation, with the most common causes of treatment discontinuation being lack of effectiveness and adverse effects.

Discontinuation rates for the biosimilars varied from 8.3% to 87.5%, and the rates of switching between products ranged from 4% to 81.5%. Among those that included information on the study design, 5 were considered prospective analyses and 6 were retrospective.

Comparing Safety, Efficacy of Trastuzumab-anns With Herceptin²

Another poster included information from a real-world study, conducted by Kaiser Permanente, that found that the safety and effectiveness of trastuzumab-anns (Kanjinti) was comparable to the reference product (Herceptin) in patients with human epidermal growth factor receptor 2 (HER2)–positive breast cancer.

Although Kanjinti’s noninferiority in early HER2-positive breast cancer was established in previous trials, evaluation of real-world outcomes is still needed to contribute information on biosimilar utilization and support providers in treatment decision-making.

There are 5 approved trastuzumab biosimilars in the United States and there are 6 in the European Union. The first FDA-approved trastuzumab biosimilar launched on the US market in July 2019. The investigators collected real-world data from patients enrolled in a Kaiser Permanente health plan in the Northern and Southern regions of California.

For inclusion, patients had to be 18 years or older, have received a breast cancer diagnosis within the previous 24 months, and have not received trastuzumab therapy within 6 months prior to the index data. After patients were dosed with their first course of trastuzumab-anns or the reference product (RP), patients were followed up with for 12 months or until death.

Of the 2173 patients that were eligible to participate, 1784 were included in the study, 893 of whom were given the biosimilar and 891 of whom were administered the RP. On average, the patients were about 57 years old and about half were White. Patients were further divided based on whether they received treatment in a curative setting (biosimilar, n = 734; RP, n = 794) or a palliative care setting (biosimilar, n = 159; RP, n = 97).

The primary end point of early treatment failure for the biosimilar was noninferior to the RP for the entire cohort and the curative setting groups. However, this was not true for the patients within the palliative care group, which may be due to the small number of patients in this group. Also, there was no significant differences between the groups regarding the multivariate Cox proportional hazards model, incidence of cardiomyopathy, or neutropenia incidence.

The observational design of the study, small sample size, and lack of generalizability outside of California were listed as limitations of the analysis.

References

1. Yun Y, Lockhart C, McDermott C. Real-world switching and discontinuation patterns of infliximab originator and biosimilars in patients with rheumatoid arthritis: a scoping review. Presented at: Academy of Managed Care Pharmacy 2022 Annual Meeting; March 29-April 1; Chicago, IL. Poster M3.
2. Nguyen D, Niu F, Ho SL, Durna L ,Hui LF, Hui RL. Evaluation of trastuzumab-anns effectiveness and safety compared to the reference product trastuzumab in patients with HER2-positive breast cancer: a non-inferiority study. Presented at: Academy of Managed Care Pharmacy 2022 Annual Meeting; March 29-April 1; Chicago, IL. Poster C12.