AUTOLOGOUS PERIPHERAL-BLOOD PROGENITOR-CELL SUPPORT FOLLOWING HIGH-DOSE CHEMOTHERAPY OR CHEMORADIOTHERAPY IN PATIENTS WITH HIGH-RISK MULTIPLE-MYELOMA

Purpose: The aims of the current study were to evaluate in patients wi th high-risk multiple myeloma (MM) the feasibility and usefulness of h igh-dose chemotherapy or chemoradiotherapy followed by hematopoietic s tem-cell support with autologous peripheral-blood progenitor cells (PB PC) harvested after high-dose cyclophosphamide (HDCYC). Patients and M ethods: Seventy-three patients with high-risk MM were entered onto the study. Before the procedure, all patients had received HDCYC to colle ct PBPC by leukapheresis. One patient died of infection after HDCYC. A ll other patients subsequently received high-dose melphalan (HDM) (140 mg/m(2)) either alone (n = 4) or associated with either busulfan (16 mg/kg; n = 4) or total-body irradiation (TBI) (8 to 15 Gy; n = 67). In addition, three of the latter patients received cyclophosphamide (120 mg/kg). Thereafter, PBPC were reinfused either alone in 61 patients o r together with back-up bone marrow cells in 11 patients in whom the g ranulocyte-macrophage colony-forming unit (CFU-GM) cell content of the leukapheresis was low. Results: One patient died of acute cardiac fai lure after reinfusion of PBPC; three patients did not respond after au tologous blood progenitor cell transplantation (ABPCT), while the othe r 68 patients achieved either a complete response (CR; n = 32) or part ial response (PR; n = 36). Thirty-six patients relapsed or progressed after a median response duration of 14.5 months (range, 3 to 43) and 1 9 of these subsequently died. Four other patients died while still res ponsive of lung cancer (n = 1) or infection (n = 3). The remaining 28 patients are currently alive and still responding with a median follow -up duration of 27 months (range, 6 to 66). The 3-year probability of survival was 66% +/- 12% (95% confidence interval [CI]) after ABPCT an d 77% +/- 51% (95% CI) from diagnosis. Conclusion: High-dose chemother apy or chemoradiotherapy followed by autologous PBPC support in MM is feasible and efficient. Further studies are needed to confirm these en couraging, although preliminary, results and to compare this technique with other therapeutic strategies. (C) 1996 by American Society of Cl inical Oncology.