A predictive model of response to erythropoietin stimulating agents in myelodysplastic syndrome: from the Canadian MDS patient registry.

Prediction of response to erythropoietin stimulating agents (ESAs) in anemic MDS patients is often based on the Nordic score. We wished to validate the Nordic score (IWG 2006 response criteria) in a larger cohort and determine if other variables such as IPSS/IPSS-R, ferritin, LDH, and a novel European ESA response score (Santini 2013) were of prognostic importance. We analyzed 208 ESA-treated MDS patients (WHO 2008 criteria) from a prospective registry. Ninety-four and 93% had lower risk scores by IPSS (low/int - 1) and IPSS-R (low/very low), respectively. Erythroid response was achieved in 94 patients (47%); responses were similar with erythropoietin (50%) and darbepoetin (39%; p = 0.2). The Nordic and European scores were both validated on univariate analysis. Variables independently predictive of response in multivariate analysis were low-risk IPSS score (OR 0.1, p = 0.0016) and serum EPO level < 100 mIU/mL (OR 8.7, p < 0.0001). We propose a new ESA response score, consisting of (a) IPSS low score (1 point) and (b) serum EPO levels < 100 mIU/ml (2 points), yielding scores ranging from 0 to 3, with response rates varying from 17 to 81%. The Nordic score has validity but we observed lower than the expected response rates in the best risk group. Our proposed scoring system appears more discriminating but needs validation.

MDM2 antagonist nutlin plus proteasome inhibitor velcade combination displays a synergistic anti-myeloma activity.

Mutliple myeloma (MM) has one of the poorest prognosis of the hematological malignancies and novel therapeutic approaches are needed. Therapeutic induction of p53 might be important to evaluate the drugs either individually or in combination. Direct inhibition of MDM2 function by an MDM2 antagonist nutlin or blocking proteasomal degradation of p53 by a selective proteasome inhibitor velcade can stabilize p53 and activate the p53 apoptotic signaling pathway. We examined if inhibition of p53-MDM2 interaction by nutlin might potentiate the cytotoxic effects of velcade in MM cell lines and primary MM samples. Nutlin or velcade resulted in a reduction in cell proliferation or viability in MM cells harboring wild type p53. Nutlin plus velcade showed a synergistic anti-myeloma activity as evidenced by a significant increase of cytotoxicity with respect to each agonist alone. These effects were accompanied by accumulation of p53 and its two immediate downstream targets, p21 and MDM2, as well as caspase activation and induction of proapoptotic targets, PUMA, BAX and BAK. The induction of p53 target genes induced by nutlin and/or velcade was further validated by gene expression profiling and expression of some selective targets was quantified by qRT-PCR. These preclinical studies provide the framework for clinical trial of nutlin, alone and in combination with conventional and novel therapies such as velcade to increase efficacy and improve patient outcome in MM.