Response to First Cycle Is the Major Predictor of Long-Term Response to Lenalidomide and Dexamethasone Therapy in Relapsed and Refractory Multiple Myeloma: Can We Spare Patients the Toxicity and Costs of Additional Agents?

BACKGROUND

Lenalidomide plus dexamethasone (Ld) is still considered an option of care for some selected patients with relapsed or refractory multiple myeloma (RRMM), despite the proven superiority of lenalidomide-based triplet therapy. Up to 20% of patients obtain long-term benefit from Ld alone. The aim of this multicenter retrospective study was to identify and characterize those with good response to Ld salvage therapy, defined as progression-free survival lasting more than 24 months.

PATIENTS AND METHODS

Patients treated with Ld in a consortium of 3 tertiary-care hospitals (Institut Català d'Oncologia) between 2009 and 2016 were prospectively registered; 227 patients had evaluable data.

RESULTS

In multivariate analysis, obtaining partial response after the first therapy cycle was the main independent factor associated with progression-free survival lasting more than 24 months. Together with standard risk cytogenetics, partial response after first cycle was also independently associated with a higher rate of complete response. Previous plasma-cell dyscrasia remained as the only baseline characteristic independently associated with long-lasting responses. High-risk cytogenetics and no history of monoclonal gammopathy of undetermined significance were the only statistically significant negative prognostic factors for overall survival. Patients who had received only one prior therapy showed a trend toward higher overall survival.

CONCLUSION

If Ld is to be considered a treatment choice, at least a partial response should be obtained after the first therapy cycle to maintain double-agent therapy safely.

Partitioning of liquid-ordered/liquid-disordered membrane microdomains induced by the fluidifying effect of 2-hydroxylated fatty acid derivatives

Cellular functions are usually associated with the activity of proteins and nucleic acids. Recent studies have shown that lipids modulate the localization and activity of key membrane-associated signal transduction proteins, thus regulating the cell's physiology. Membrane Lipid Therapy aims to reverse cell dysfunctions (i.e., diseases) by modulating the activity of membrane signaling proteins through regulation of the lipid bilayer structure. The present work shows the ability of a series of 2-hydroxyfatty acid (2OHFA) derivatives, varying in the acyl chain length and degree of unsaturation, to regulate the membrane lipid structure. These molecules have shown greater therapeutic potential than their natural non-hydroxylated counterparts. We demonstrated that both 2OHFA and natural FAs induced reorganization of lipid domains in model membranes of POPC:SM:PE:Cho, modulating the liquid-ordered/liquid-disordered structures ratio and the microdomain lipid composition. Fluorescence spectroscopy, confocal microscopy, Fourier transform infrared spectroscopy and differential detergent solubilization experiments showed a destabilization of the membranes upon addition of the 2OHFAs and FAs which correlated with the observed disordering effect. The changes produced by these synthetic fatty acids on the lipid structure may constitute part of their mechanism of action, leading to changes in the localization/activity of membrane proteins involved in signaling cascades, and therefore modulating cell responses.