Evidence to Support Zarxio Use Presented at AMCP

Two posters presented at the Academy of Managed Care Pharmacy bolstered the case for moving away from the use of the originator filgrastim product Neupogen®.

In a study from Magellan Rx Management, Scottsdale, AZ, the researchers grouped both Zarxio® and Granixzarxio® together as alternatives to the originator filgrastim in the granulocyte-colony-stimulating factor (G-CSF) category as supportive oncological care. They studied the effect of a step edit, requiring the use of either Zarxio or Granix first, and its effect on utilization trends and cost savings among 2.7 million covered lives.

The step edit was implemented in October 2016 and the results for the fourth quarter of 2016 were compared with utilization and cost data from the first three quarters of that year. In terms of utilization, the marketshare of Neupogen dropped from 18% in early 2016 to only 2% by the third quarter of 2017. As expected, the drop in utilization occurred just after the step edit was introduced a year ago. The combined marketshare of Granix and Zarxio jumped from 9% to 21% over that time, but the dominant player in the G-CSF space, Neulasta® (pegfilgrastim), maintained utilization, rising from 73% to 77%. Over the one-year period since the step edit was introduced, the authors calculated a cost savings of $662,278; the cost savings in the quarter after the policy change was $106,980, or approximately 8% of the total spent for the G-CSF category.

The authors noted that the cost savings were calculated using wholesale acquisition cost (WAC) not average sales price (ASP), and manufacturer discounts or rebates were not considered in the estimates.

The second poster, sponsored by Sandoz, was a retrospective claims analysis of the incidence of febrile neutropenia in patients receiving chemotherapy who were treated with Zarxio or Neupogen. This study covered 13 months of claims (from Optum) from 162 patients taking Zarxio compared with 3,297 receiving Neupogen. The groups did not differ significantly in terms of demographics, insurance, or tumor type.

The researchers found that the incidence of neutropenia (in addition to fever and/or infection) was nonsignificantly greater in those receiving the biosimilar compared with the reference product (2.3% vs. 1.7%, respectively).

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