High-Dose Vincristine Sulfate Liposome Injection, for Advanced, Relapsed, or Refractory Philadelphia Chromosome-Negative Acute Lymphoblastic Leukemia in an Adolescent and Young Adult Subgroup of a Phase 2 Clinical Trial.

PURPOSE

A study of vincristine sulfate (VCR) liposome injection (VSLI) was conducted in patients with advanced, relapsed, or refractory, Philadelphia chromosome-negative acute lymphoblastic/lymphocytic leukemia (ALL). A retrospective subgroup analysis of the results was performed to evaluate the safety and efficacy of VSLI in the adolescent and young adult (AYA) patients.

METHODS

Of the 65 patients treated in the pivotal Phase 2 Study HBS407 (NCT00495079), 44 patients were aged ≤39 years (median 27 [range 19-39] years) and were included in this analysis. Patients received VSLI (2.25 mg/m intravenously every 7 ± 3 days) without dose capping or concurrent steroid administration in continuous 28-day cycles.

RESULTS

VSLI was well tolerated in the AYA patients over a median of 5 (range 1-15) doses administered. One-third of patients (36%) experienced treatment-related serious adverse events (AEs) with peripheral neuropathy (7%), tumor lysis syndrome (7%), and febrile neutropenia (5%) in >1 patient. Neuropathy-associated AEs occurred in 82% patients; no neuropathy-related deaths occurred. The rate of complete remission (CR) (with or without complete blood count recovery) by investigator assessment was 25% in AYA patients, and the overall response rate was 39%. Median leukemia-free survival in AYA patients attaining CR was 135 (range 32-463) days, and median overall survival was 141 (range 13-620) days.

CONCLUSION

VSLI provided a meaningful clinical benefit to AYA patients with ALL, and its safety profile was comparable to that of VCR despite the delivery of higher doses (individual and cumulative).