Pegfilgrastim biosimilar MYL-1401H exerts equivalent efficacy to reference product in preventing chemotherapy-induced neutropenia in patients with breast cancer

Pegfilgrastim is indicated for reducing duration of neutropenia and incidence of febrile neutropenia associated with chemotherapy regimens in cancer patients. This study compared the prophylactic efficacy of MYL-1401 biosimilar versus reference pegfilgrastim in a guideline-recommended sensitive population of breast cancer patients receiving high-risk chemotherapy.

Biologics have great therapeutic potential but are associated with a high cost, which consequently affects their availability – the two principal limitations that biosimilars are designed to address. Among the first biosimilars to receive EMA/FDA approval was filgrastim, indicated for the prophylaxis of chemotherapy-induced neutropenia (CIN), infections, and dose reductions in cancer patients. Whereas filgrastim is administered daily, its long-acting form, pegfilgrastim, can be given once per chemotherapy cycle. MYL-1401H is a pegfilgrastim biosimilar with preclinical and pharmacokinetic/pharmacodynamic data that supports equivalence to the originator drug. This phase III safety and efficacy trial was designed to confirm equivalence between MYL-1401H and pegfilgrastim for CIN prophylaxis.

The study included patients with breast cancer eligible to receive adjuvant chemotherapy with docetaxel/doxorubicin/cyclophosphamide (TAC) chemotherapy every 3 weeks for six cycles. CIN prophylaxis was administered 24 hours after day 1 of each chemotherapy cycle.

Findings

Mean duration of severe neutropenia in both the MYL-1401H and pegfilgrastim groups was 1.2 days, demonstrating equivalent efficacy between the two groups. Secondary endpoints including absolute neutrophil count (ANC) nadir and time to ANC nadir were also similar. Across all cycles, febrile neutropenia (FN) occurred in 6% patients receiving MYL-1401H and 2% pegfilgrastim, suggesting noninferiority of this parameter. All cases of FN were of short duration and no infections required treatment. Similar rates of treatment-emergent adverse events (TEAEs) were observed between groups. One patient in the pegfilgrastim group and no patients in MYL-1401H group had treatment-induced antidrug antibodies.

In this study MYL-1401H demonstrated equivalent efficacy to pegfilgrastim for prophylaxis of CIN in patients with breast cancer undergoing TAC chemotherapy. Both products were generally well tolerated, with no clinically meaningful differences of TEAEs.

Key takeaway

Long-acting pegfilgrastim is indicated for the prophylaxis of CIN, infections, and dose reductions in cancer patients. This phase III trial demonstrated equivalent efficacy of the biosimilar MYL-1401H to the originator product.