A systematic review of comparative schedule-related toxicities with maintenance rituximab in follicular and mantle cell lymphomas.

Abstract We conducted a systematic review of grade 3/4 adverse events (AEs) reported in prospective trials enrolling patients with follicular lymphoma (FL) and mantle cell lymphoma (MCL) receiving maintenance rituximab (MR). Random-effects models were used to calculate summary estimates and 95% confidence intervals for the proportion of AEs occurring during MR. Differences by induction program, histology, setting and MR schedule were examined by stratified analyses and univariate random-effects meta-regression. Eleven trials met the search criteria, with nine sufficiently reporting AEs during the MR phase. Of 1009 patients receiving MR, the proportion experiencing cumulative grade 3/4 toxicity was 24% (95% confidence interval [CI]: 14-36%). Patients receiving MR every 6 months as four weekly infusions for 2 years had significantly less toxicity compared with those receiving MR every 2 months (10% vs. 28%; p = 0.035). Patients treated with rituximab alone during induction had fewer toxicities compared to those treated with rituximab plus chemotherapy induction (12% vs. 35%; p = 0.031). Myelosuppression and infections were the most common toxicities. Our literature analysis suggests that MR given every 6 months and rituximab alone as induction may be associated with fewer grade 3/4 AEs for patients with FL and MCL; however, assessing the true independent impact of induction regimens and schedule on toxicity will require prospective trials.

Radicicol activates heat shock protein expression and cardioprotection in neonatal rat cardiomyocytes.

Heat shock proteins (HSPs) constitute an endogenous cellular defense mechanism against environmental stresses. In the past few years, studies have shown that overexpression of HSPs can protect cardiac myocytes against ischemia-reperfusion injury. In an attempt to increase the HSPs in cardiac tissue, we used the compound radicicol that activates HSP expression by binding to the HSP 90 kDa (HSP90). HSP90 is the main component of the cytosolic molecular chaperone complex, which has been implicated in the regulation of the heat shock factor 1 (HSF1). HSF1 is responsible for the transcriptional activation of the heat shock genes. In the present study, we show that radicicol induces HSP expression in neonatal rat cardiomyocytes, and this increase in HSPs confers cardioprotection to these cardiomyocytes. We also show that radicicol induction of the HSP and cardioprotection is dependent on the inhibition of HSP90 in cardiomyocytes. These results indicate that modulation of the active HSP90 protein level plays an important role in cardioprotection. Therefore, compounds, such as radicicol and its possible derivatives that inhibit the function of HSP90 in the cell may represent potentially useful cardioprotective agents.