A Prospective Phase II Study on Tandem Autografting-Nonmyeloablative Allografting for Newly Diagnosed Myeloma: Final Results of the Gruppo Italiano Trapianto Midollo Osseo.

The development of nonmyeloablative conditionings has recently reduced the transplant-related mortality (TRM) and extended the eligible age for transplantation up to 65–70 years. From January 2000 to June 2005, 106 newly diagnosed patients younger than 65 years were enrolled in a prospective phase II study at 15 Italian Centers. Fifty-eight were also previously described in a comparison of autografting with allografting based on a genetic randomisation (Bruno et al. N Engl J Med 2007). Here we report on a larger GITMO experience with a longer follow-up. Induction chemotherapy consisted of VAD-based regimens, followed by a cytoreductive autograft with melphalan 200 mg/m², and by a non-myeloablative 2 Gy TBI-based allograft from an HLA-identical sibling. Graft-vs-host disease (GVHD) prophylaxis included cyclosporin and mycophenolate mofetil. Primary endpoints were overall (OS) and event-free (EFS) survivals. Secondary endpoint was TRM. One-hundred-two (96%) patients, median age 54 (30–65), completed the tandem program whereas 4 withdrew their consent. After a median follow-up of 54 (21–94) months, OS was not reached and median EFS was 35 (31–56) months post-transplant. Incidences of acute grade II-IV GHVD and extensive chronic GVHD were 40% and 50% respectively. Fourteen (13%) patients died from TRM, 14 (13%) from disease progression, 2 from lung cancer (2%) and 1 from lymphoma (1%). Overall response, defined as complete (CR) and partial remission, was 91% (93/102), with 53 patients achieving CR. Overall 39/102 patients relapsed, however only 8/53 of those who reached CR post-transplant. By multivariate-analysis disease response prior to allografting was significantly associated with longer OS (HR 0.27, CI 0.09–0.80, p<0.018) and longer EFS (HR 0.23, CI 0.11–0.49, p<0.001). Interestingly, chronic GVHD was not correlated with either the achievement of post-transplant CR (HR 0.87, CI 0.45–1.65, p<0.66) or its duration (HR 0.79, CI 0.45–1.40, p<0.42). Presence of del(13) was evaluated only in a subset of 39 patients: 13 carried del(13) and 26 did not. OS was not reached in the patients without del(13) and was 52 months in patients with del(13) (p=0.32), however EFS was not reached in the patients without del(13) whereas was 27 months for patients with del(13) (p=0.04). Given the encouraging results, the design of prospective studies that incorporate new drugs to cytoreduce the disease pre-transplant and enhance graft-vs.-myeloma are warranted to lower relapse rates and improve clinical outcomes.