Evolving paradigms in the treatment of relapsed/refractory multiple myeloma: increased options and increased complexity.

The use of modern therapies such as thalidomide, bortezomib and lenalidomide coupled with upfront high-dose therapy and autologous stem cell transplant (ASCT) has resulted in improved survival in patients with newly diagnosed multiple myeloma (MM). However, patients with relapsed/refractory multiple myeloma (RRMM) often have poorer clinical outcomes and might benefit from novel therapeutic strategies. Emerging therapies, such as deacetylase inhibitors, monoclonal antibodies and new proteasome inhibitors, appear promising and may change the therapeutic landscape in RRMM. A limited number of studies has shown a benefit with salvage ASCT in patients with RRMM, although there remains ongoing debate about its timing and effectiveness. Improvement in transplant outcomes has re-ignited a debate on the timing and possible role for salvage ASCT and allogeneic stem cell transplant in RRMM. As the treatment options for management of patients with RRMM become increasingly complex, physicians must consider both disease- and patient-related factors in choosing the appropriate therapeutic approach, with the goal of improving efficacy while minimizing toxicity.

Six-month freedom from treatment failure is an important end point for acute GVHD clinical trials.

We studied the American Society for Blood and Marrow Transplantation (ASBMT) 6-month (m) freedom from treatment failure (FFTF) as a predictor of survival for patients with acute GVHD (aGVHD) requiring treatment. Adult patients undergoing allogeneic hematopoietic cell transplant (HCT) from February 2007 to March 2009 who were enrolled in a prospective biomarker clinical trial and developed aGVHD requiring systemic corticosteroids by day +100 were included (N=44). Six-month FFTF was defined as per the ASBMT guidelines (absence of death, malignancy relapse/progression or systemic immunosuppression change within 6 months of starting steroids and before chronic GVHD development). aGVHD was treated with systemic corticosteroids in 44 patients. Day 28 response after steroid initiation (complete response+very good partial response+partial response) occurred in 38 (87%) patients, but only 28 (64%) HCT recipients met the 6-m FFTF end point. Day 28 response predicted 6-m FFTF. Achieving 6-m FFTF was associated with improved 2-year (y) OS (81% vs 48%; P=0.03) and decreased 2-y non-relapse mortality (8% vs 49%; P=0.01). In multivariate analysis, 6-m FFTF continued to predict improved OS (hazard ratio, 0.27; P=0.03). The 6-m FFTF end point measures fixed outcomes, predicts long-term therapeutic success and could be less prone to measurement error than aGVHD clinical response at day 28.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for acute leukemias: 'what is the best recipe?'.

Reduced-intensity stem cell transplantation (RIST) has been shown to be a safe and useful alternative transplant method for patients including elderly and medically unfit patients. RIST conditioning regimens vary widely in the intensity of myeloablation, immunoablation, and antileukemia effects, and thus optimal regimen for each disease entity is yet to be determined. Most reports on RIST to date are small, single-institution experiences or retrospective studies with heterogeneous patient populations and primary diseases, complicating any direct comparison between studies. In acute myeloid leukemia (AML), moderate-intensity regimens may be effective, achieving 30-70% 1-year disease-free survival in various series, but minimal-intensity regimens are associated with high relapse rates. In acute lymphoblastic leukemia (ALL), not even moderate-intensity regimens are effective and most patients with advanced ALL relapse post transplant. Thus, the risk/benefit ratios of graft-versus-host disease/graft-versus-leukemia effect differ among diseases. Larger, prospective, multi-center clinical trials are needed to determine the best use of RIST in hematologic malignancies.

Pegfilgrastim after high-dose chemotherapy and autologous peripheral blood stem cell transplant: phase II study.

Pegfilgrastim is equivalent to daily filgrastim after standard dose chemotherapy in decreasing the duration of neutropenia. Daily filgrastim started within 1-4 days after autologous stem cell transplant (ASCT) leads to significant decrease in time to neutrophil engraftment. We undertook a study of pegfilgrastim after high-dose chemotherapy (HDC) and ASCT. In all, 38 patients with multiple myeloma or lymphoma, eligible to undergo HDC and ASCT, were enrolled. Patients received a single dose of 6 mg pegfilgrastim subcutaneously 24 h after ASCT. There were no adverse events secondary to pegfilgrastim. All patients engrafted neutrophils and platelets with a median of 10 and 18 days, respectively. The incidence of febrile neutropenia was 49% (18/37). Neutrophil engraftment results were compared to a historical cohort of patients who received no growth factors or prophylactic filgrastim after ASCT. Time to neutrophil engraftment using pegfilgrastim was comparable to daily filgrastim and was shorter than in a historical group receiving no filgrastim (10 vs 13.7 days, P<0.001). Pegfilgrastim given as a single fixed dose of 6 mg appears to be safe after HDC and ASCT. It accelerates neutrophil engraftment comparable to daily filgrastim after ASCT. Pegfilgrastim may be convenient to use in outpatient transplant units.