High-dose therapy with single autologous transplantation versus chemotherapy for newly diagnosed multiple myeloma: A systematic review and meta-analysis of randomized controlled trials.

Myeloablative high-dose therapy and single autologous stem cell transplantation (HDT) is frequently performed early in the course of multiple myeloma, supported by some randomized controlled trials (RCTs) indicating overall survival (OS) and progression-free survival (PFS) benefit compared with nonmyeloablative standard-dose therapy (SDT). Other RCTs, however, suggest variable benefit. We therefore undertook a systematic review and meta-analysis of all RCTs evaluating upfront HDT versus SDT in myeloma. The primary objective was to quantify OS benefit with HDT, with PFS benefit a secondary objective. Anticipating heterogeneity, sensitivity and subgroup analyses were undertaken to assess robustness of results. Assessment of harms (treatment-related mortality) was also undertaken. We searched the PubMed, Embase, and Cochrane Collection of Controlled Trials databases using the terms myeloma combined with autologous or transplant or myeloablative or stem cell. In total, 3407 articles were accessed, and 10 RCTs prospectively comparing upfront HDT with SDT, with > or =2-year follow-up, and reporting OS benefit on an intent-to-treat basis were identified. Two reviewers independently extracted study characteristics, interventions, and outcomes. Hazard ratios (with 95% confidence interval) were determined. Nine studies comprising 2411 patients were fully analyzed. Significant heterogeneity was present. The combined hazard of death with HDT was 0.92 (95% confidence interval, 0.74-1.13). The combined hazard of progression with HDT was 0.75 (95% confidence interval, 0.59-0.96). The totality of the randomized data indicates PFS benefit but not OS benefit for HDT with single autologous transplantation performed early in multiple myeloma. Sensitivity and subgroup analyses supported the findings and indicated that, contrary to current reimbursement criteria, PFS benefit with upfront HDT is not restricted to chemoresponsive myeloma. However, the overall risk of developing treatment-related mortality with HDT was increased significantly (odds ratio, 3.01; 95% confidence interval, 1.64-5.50). Hence, evaluating alternative therapeutic options upfront may also be reasonable.

Granzyme B and the downstream granzymes C and/or F are important for cytotoxic lymphocyte functions.

Although the functions of granzyme A (GzmA) and GzmB are well-defined, a number of orphan granzymes of unknown function are also expressed in cytotoxic lymphocytes. Previously, we showed that a targeted loss-of-function mutation for GzmB was associated with reduced expression of several downstream orphan granzyme genes in the lymphokine-activated killer cell compartment. To determine whether this was caused by the retained phosphoglycerate kinase I gene promoter (PGK-neo) cassette in the GzmB gene, we retargeted the GzmB gene with a LoxP-flanked PGK-neo cassette, then removed the cassette in embryonic stem cells by transiently expressing Cre recombinase. Mice homozygous for the GzmB null mutation containing the PGK-neo cassette (GzmB-/-/+PGK-neo) displayed reduced expression of the closely linked GzmC and F genes in their MLR-derived CTLs and lymphokine-activated killer cells; removal of the PGK-neo cassette (GzmB-/-/DeltaPGK-neo) restored the expression of both genes. Cytotoxic lymphocytes derived from mice with the retained PGK-neo cassette (GzmB-/-/+PGK-neo) had a more severe cytotoxic defect than those deficient for GzmB only (GzmB-/-/DeltaPGK-neo). Similarly, GzmB-/-/+PGK-neo mice displayed a defect in the allogeneic clearance of P815 tumor cells, whereas GzmB-/-/DeltaPGK-neo mice did not. These results suggest that the retained PGK-neo cassette in the GzmB gene causes a knockdown of GzmC and F expression, and also suggest that these granzymes are relevant for the function of cytotoxic lymphocytes in vitro and in vivo.