At ASH 2017

ATLANTA (FRONTLINE MEDICAL NEWS)– The rate of venous thromboembolism (VTE) in patients with non-Hodgkin lymphoma (NHL) treated with lenalidomide is similar to that seen in multiple myeloma, according to results of recent systematic review and meta-analysis of trials representing more than 10,000 treatment cycles.

Although rates of VTE for NHL and myeloma could not be directly compared statistically, the finding may have clinical implications for NHL patients, said lead study author Samuel Yamshon, MD, an internal medicine resident at Cornell University, New York.

“Although outpatient VTE prophylaxis is not currently recommended, it should be carefully considered in patients with lymphoma being treated with lenalidomide, especially those receiving lenalidomide as a single agent,” Dr. Yamshon said in a presentation of the results at the annual meeting of the American Society of Hematology.

The rate of thrombosis in patients with B cell NHL who received lenalidomide treatment was 0.75 events per 100 patient-cycles, according to results of the meta-analysis, which was based on 28 articles including 10,332 cycles of lenalidomide received by patients with B-cell NHL.

Reported rates of thrombosis in previously untreated myeloma patients treated with lenalidomide are between 0.7 and 0.8 per 100 patient-cycles, Dr. Yamshon said in his presentation.

Notably, single-agent lenalidomide was linked with a significantly increased risk of thrombosis compared with lenalidomide treatment in combinations. The relative risk of VTE for lenalidomide as a single agent versus lenalidomide in combination was 2.01 (95% confidence interval, 1.28-3.16; P = .002), according to the presented data.

The investigators were unsure why single-agent lenalidomide appeared to have caused increased rates of thrombosis compared to lenalidomide in combinations. “Perhaps patients treated with additional agents have a lower tumor burden, leading to less venous obstruction causing clots, or perhaps there’s a direct interaction between lenalidomide and tumor leading to effects on the vasculature and mediators of coagulation,” Dr. Yamshon said.

Chemotherapy and biologic combinations had somewhat different VTE rates when compared to single-agent lenalidomide. The rate in patients receiving lenalidomide alone was 1.06 events per 100 patient-cycles, compared with 0.73 and 0.41 events per 100 patient-cycles, respectively, for lenalidomide plus chemotherapy and lenalidomide plus biologics.

However, the lower event rate with lenalidomide and biologics compared with lenalidomide and chemotherapy was a “nonsignificant trend” that was likely caused by differences in patient characteristics between the two cohorts, according to Dr. Yamshon.

None of the studies included in the meta-analysis were prospectively designed to measure VTE as a primary or secondary outcome, Dr. Yamshon noted in a discussion of the study’s limitations.

Further studies are warranted to determine lenalidomide’s effect on the vasculature and how it effects mediators of coagulation, he added.

Based on the current results, Dr. Yamshon said it may be reasonable to consider VTE prophylaxis in NHL patients receiving lenalidomide.

“If we’re going to be recommending outpatient VTE prophylaxis in everyone on lenalidomide in multiple myeloma, and the rates (of VTE) are the same, I think it certainly makes sense based on the data to recommend it,” he said in a question-and-answer session.

Dr. Yamshon reported no conflicts related to the study. Coauthors reported disclosures related to Roche, Celgene, Seattle Genetics, Pharmacyclics, Cell Medica, Janssen, and AstraZeneca.

SOURCE: Yamshon S et al. Abstract 677 .