Pegfilgrastim Prefilled Syringe vs. On-Body Injector: Study Finds no Meaningful Differences in Clinical or Economic Outcomes

The pegfilgrastim biosimilar story has widely been viewed as a qualified success. The field is a bit crowded: there are four biosimilar competitors, and more to come, in addition to the originator product Neulasta® and Neulasta Onpro® on-body injector. Amgen, the manufacturer of Neulasta, has seen ongoing, decreasing marketshare of the prefilled syringe, but it has been bolstered by the continuing dominance of OnPro. No biosimilar manufacturer has brought its own on-body injector to the market.

The on-body injector is preferred by patients and doctors, based on its convenience and reduced need for office visits. However, a study published in the September issue of the Journal of Managed Care and Specialty Pharmacy revealed that real-world economic and clinical outcomes between the two formulations were nearly identical. This may mean that any adherence benefit that may arise from the use of the on-body injector does not translate into clinical outcomes. This could provide important support for health plans and insurers that seek to prefer biosimilars over the reference formulation.

The study was funded by Sandoz, manufacturer of one of the pegfilgrastim biosimilars (Ziextenzo®). All of the biosimilars available today are available only in prefilled syringe form.

Some Difference on Costs, Little on Care

The retrospective study was conducted using a large claims database. Researchers from Sandoz and Banner University Medical Center and University of Arizona Cancer Center identified 2,170 patients with either breast cancer or non-Hodgkin lymphoma receiving myelosuppressive chemotherapy and who were prescribed pegfilgrastim to prevent febrile neutropenia over an 18-month period ending May 31, 2018. Half had used the on-body injector and half had pegfilgrastim administered via the prefilled syringe.

The mean incidence of febrile neutropenia during the first chemotherapy cycle was 1.01% for patients using the on-body injector compared with 1.48% for those using the prefilled syringe (P = .34). The difference narrowed further if all chemotherapy cycles were considered (0.91% vs. 1.22%, respectively, P = .21).

From an economic standpoint, the mean total all-cause adjusted costs between the two study groups were not statistically significant, although the prefilled syringe cohort had a slight edge ($21,745 vs. $20,655, P = .055). Patients utilizing OnPro had significantly greater outpatient costs ($14,737 vs $10,961, respectively, P < .001), although mean pharmacy costs were higher for the patients using the prefilled syringe form of pegfilgrastim ($226 vs. $319, respectively, P < .001). The researchers could not find any statistically significant associations in terms of emergency department visits or  hospitalizations between the study groups. However, for 409 patients who experienced at least one hospital stay, those receiving OnPro had shorter mean hospital stays than those in the prefilled syringe groups (3.8 vs. 4.7 days, P < .001).

It should be noted that the data collection period in this study ended before the first pegfilgrastim was approved (Fulphila®, in June 2018). Therefore, this study solely compared clinical and economic outcomes associated with Neulasta and Neulasta OnPro. The introduction of biosimilars has significantly lowered the net costs of the class (including OnPro). As a result, the economic conclusions–especially regarding pharmaceutical costs–would likely be different if considered in today’s terms.

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