Does Low-Molecular-Weight Heparin Influence the Antimyeloma Effects of Thalidomide? A Retrospective Analysis of Data from the GIMEMA, Nordic and Turkish Myeloma Study Groups

Background/Aim: Low-molecular-weight heparin (LMWH) has been shown to prolong survival among patients with solid tumors, but its role among myeloma patients is unknown. Patients: Data from the GIMEMA (Gruppo Italiano Malattie Ematologiche dellʼAdulto), Nordic and Turkish myeloma study groups comparing melphalan and prednisolone with (MPT, n: 404) or without thalidomide (MP, n: 393) are analyzed for effects of LMWH. Forty percent (159/394) of the patients on MPT and 7.4% (29/390) in the MP arm received LMWH. Results: Thalidomide improved response and progression-free survival (PFS). Regardless of thalidomide treatment, response rate was higher among those receiving LMWH vs. none vs. other anticoagulants (58.1 vs. 44.9 vs. 50.4%, p = 0.01). PFS was significantly longer (median 32 vs. 21 and 17 vs. 17 months, p = 0.004) only among international scoring system (ISS) I patients receiving MPT ± LMWH vs. MP ± LMWH. The group of MPT patients who also received LMWH had a better OS compared to those who did not [45 months, 95% confidence interval (CI) 27.7-62.3, vs. 32 months, 95% CI 26.1-37.9; p = 0.034]. When multivariate analysis was repeated in subgroups, thalidomide was no longer a significant factor (response, PFS) among those receiving LMWH. Conclusion: Addition of LMWH to MPT, in particular in patients with low ISS, suggests additive effects, but the results are limited by the retrospective design of our study.