Proposed biosimilar LA-EP2006 and reference pegfilgrastim were comparable regarding efficacy and safety in the prevention of neutropenia in patients with early stage breast cancer receiving TAC, according to results of a study published in The Oncologist.1

Pegfilgrastim, which is used for the prevention of chemotherapy-induced neutropenia, has no approved biosimilar. Researchers conducted the phase 3, randomized, double-blind PROTECT-2 trial to compare LA-EP2006 with reference pegfilgrastim in patients with early stage breast cancer receiving adjuvant or neoadjuvant myelosuppressive  chemotherapy.

A total of 308 patients were randomly assigned to receive LA-EP2006 or pegfilgrastim. Each received TAC (intravenous docetaxel 75 mg/m2, doxorubicin 50 mg/m2, and cyclophosphamide 500 mg/m2 on day 1 of each cycle, for 6 or more cycles. Pegfilgrastim or the biosimilar were administered subcutaneously (6 mg in 0.6 mL) on day 2 of each cycle.

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The primary endpoint was duration of severe neutropenia (DSN) during cycle 1 (number of consecutive days with an absolute neutrophil count <0.5 × 109/L), with equivalence confirmed if 90% and 95% confidence intervals were within a 1-day margin.

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Results showed that DSN was equivalent between the groups at mean ± SD 1.36 ± 1.13 (LA-EP2006, n = 155) and 1.19 ± 0.98 (reference, n = 153) in cycle 1. With a treatment difference (reference minus LA-EP2006) of −0.16 days (90% CI, −0.36 to 0.04; 95% CI, −0.40 to 0.08), LA-EP2006 was equivalent to reference pegfilgrastim. Secondary efficacy parameters were similar between groups across cycles. Safety profiles were also similar. No neutralizing antibodies against pegfilgrastim, filgrastim, or polyethylene glycol were detected.

Reference

  1. Blackwell K, Donskih R, Jones CM, et al. A comparison of proposed biosimilar LA-EP2006 and reference pegfilgrastim for the prevention of neutropenia in patients with early-stage breast cancer receiving myelosuppressive adjuvant or neoadjuvant chemotherapy: pegfilgrastim randomized oncology (supportive care) trial to evaluate comparative treatment (PROTECT-2), a phase III, randomized, double-blind trial [published online ahead of print April 18, 2016]. Oncologist. doi: 10.1634/theoncologist.2016-0011.

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Breast Cancer Side-Effect Management