Background. Immunomodulator drugs (IMiDs) are associated with an increased risk of thromboembolic events (TE). Multiple Myeloma patients (MM) that can not benefit from novel agents, including IMiDs, only have 9 months survival. IMiDs must be stopped when TE occurs with the consequence of potential shortened life expectancy. MELISSE was designed to prospectively evaluate the incidence and risk factors of venous TE (VTE) associated with IMiDs in MM. We have presented the interim analysis of MELISSE at ASH 2010. A reduced incidence rate of early VTE was observed when a prophylaxis for VTE was started as compared to patients that had no prophylaxis. Interestingly, we also reported that most of the patients had received aspirin, while aspirin is not considered to exert any venous prophylactic effect. LMWH was primarily proposed to patients with high risk of TE according to physician’s evaluation. We present the final analysis of MELISSE with updated results at 1 year.
Method. A total of 524 MM treated with IMiDs-based therapy were included in 52 IFM centers. VTE prophylaxis was recommended prior to start IMiDs, the choice of which was left at the discretion of the investigator. Patients gave written informed consent according to the declaration of Helsinki. The physicians were to record the risk of VTE occurrence, categorized as low, moderate and high, based on guidelines and their own appreciation of the risk. Occurrence of any VTE was to be recorded along with the management of the event and the patient’s outcome. The data were collected at entry in the study, and then after 4 and 12 months.
Results. The median age was 70 years old, with 64.67% of patients >65 years old. Overall 36.0% had thalidomide-based and 64.0% had lenalidomide-based therapy, with 180 patients in first line and the remaining patients in 2nd and 3rd lines of therapy. The observed repartition of TE risk factors was as expected in a European population with myeloma. The risk of VTE was assessed as high in 14.2% patient and small or intermediate otherwise. Interestingly, approximately 70% of patients rated as low and intermediate risk received aspirin as a routine prophylaxis for VTE as compared to 20% in high risk patients. LMWH was primarily given to high risk patients, 45.8%. Surprisingly, 16.0% of patients had no VTE prophylaxis.
Investigators recorded 29 (5.5% annual incidence rate) TE at 12 months, including 12 associated with PE. The incidence rate of TE was similar within the first 4 months (early occurrence, 3.5%) versus after 4 months (late, 2.5%). We have not identified any risk factor that would explain early versus late occurrence of VTE. Interestingly, the incidence of VTE was higher in patients that had no prophylaxis treatment, 8.5%, as compared to 4.4% and 5.9% in the LMWH and aspirin groups, respectively. There was no PE recorded in patients that were on LMWH prophylaxis. The VTE was equally breakdown across the 3 groups of risk factors. The bleeding adverse events were reported for 27 patients, mainly patients with aspirin. We isolated a model with 3 variables that independently predicted a higher risk to develop VTE in the multivariate model, and that comprised the male gender [OR 4.31 (95% CI 1.60 - 13.90)], the smoking habit [6.76 (1.73-22.42)] and the association to EPO [2.66 (1.04-6.58)]. Aspirin showed no significance, but with a p value at 0.55. The multivariate analysis is limited as certain subgroups with high risk factors might have received the optimal VTE prophylaxis, such as patients with bed rest and patients with prior history of VTE. These 2 groups rarely had aspirin. Survival data will be updated and presented at ASH 2011.
Conclusion. This study further demonstrates that TE prophylaxis is required for MM treated with IMiDs-based therapy. There is a slight increase risk of VTE/PE with the use of aspirin as compared to LMWH, but a significant increase in bleeding events. Although we have identified risk factors of VTE in MM treated with IMiDs, for the first time, we could not identified VTE risk factors to guide investigators between LMWH and aspirin-based prophylaxis. The optimal dose and duration of LMWH remains to be determined.