A phase II study of two cycles of high-dose chemotherapy with autologous stem cell support in patients with metastatic breast cancer who meet eligibility criteria for a single cycle.

Multi-cycle high-dose chemotherapy with autologous stem cell support (HDC-ASCS) may improve the results obtained with single-cycle HDC-ASCS in metastatic breast cancer (MBC). However, the tolerability and efficacy of additional cycles of HDC-ASCS in patients selected using standard eligibility criteria for single cycle HDC-ASCS is uncertain. Twenty-nine patients with MBC and a CR or PR to induction chemotherapy were selected by standard institutional eligibility criteria for single-cycle HDC-ASCS. Cycle 1 HDC-ASCS (cyclophosphamide 6 g/m2; mitoxantrone 70 mg/m2; carboplatin 800 mg/m2) was followed by a planned second cycle (etoposide 1.6 g/m2; thiotepa 800 mg/m2; carboplatin 800 mg/m2 modulated by tamoxifen 120 mg/m2/day x 5 days) with a median interval of 3.2 months. CR rate was 20% after induction chemotherapy and 33% and 54% after HDC cycles I and II, respectively. Sixteen patients (55%) failed to complete HDC cycle II within 200 days because of disease progression, toxicity, inadequate stem cell collection, insurance denials or patient choice. Median progression-free survival (PFS) for all 29 patients entered is 301 days from date of HDC cycle I and actuarial PFS at 2 years is 35%. For the 13 patients who received the two cycles of HDC-ASCS, actuarial PFS at 2 years was 54% (P = NS compared to those receiving only one cycle). These data show that a second cycle of full-dose intensity HDC-ASCS may increase the proportion of patients with MBC that achieve CR and may increase PFS. However, a large proportion of patients that complete HDC-ASCS cycle I may fail to proceed to cycle II in a timely fashion. Bone Marrow Transplantation (2000) 25, 519-524.