Blood Clot and Bleeding Risk in B-cell Lymphomas: Gene Changes and CAR T-cell Therapy Insights

In this article, you will learn findings presented at the 2025 ASH conference about how certain gene changes and CAR T-cell therapy may affect clotting and bleeding risk for people with B-cell lymphomas.

Certain gene changes may raise blood clot risk in lymphoma

Venous thromboembolism (VTE) means a blood clot forms in a deep vein, like the leg, then breaks off and travels to an area like the lungs. VTE can be life-threatening. And people with lymphoma are at a higher risk for this dangerous clot. A study used tumor sequencing data from 3,403 people with B-cell lymphomas to look for gene changes tied to VTE risk. 

Overall, 2.4% of patients had VTE within one year since the start of monitoring, but the risk was higher in people with aggressive lymphomas than slow-growing ones. DLBCL had the highest one-year VTE rate at 4.9%. Researchers found that alterations in genes BIRC3, CDKN2A, CDKN2B, and PRDM1 were linked to higher VTE risk across lymphoma types. 

For patients, this research could eventually help identify who may need closer clot monitoring or prevention strategies. 

Read this abstract: Genomic profiling identifies somatic alterations predicting thromboembolic risk in patients with lymphoma 

Bleeding after CAR-T may be more common than people realize 

A Dutch study focused on people with LBCL who had been treated with the CAR T-cell therapy axi-cel. They tracked whether patients experienced any blood clots or bleeding during the year after their CAR-T infusion. Clots occurred in 6.6% of patients and bleeding in 11%. 

Bleeding was linked to worse overall survival. Risk rose in people who had moderate-to-severe ICANS, very low platelets, and those taking full-dose blood thinners around infusion. Preventive-dose blood thinners did not appear to raise bleeding risk compared with no blood thinners, but full-dose blood thinners did. 

The goal is not to avoid blood thinners when they’re needed, but to match the intensity of blood thinners to your risk during a time when platelets can drop, like after CAR-T. 

Ask your lymphoma specialist how this research can be applied to your care. If you have a history of blood clots or take blood thinners, this data may help guide important conversations with your doctor before CAR-T. 

Read this abstract: High risk of bleeding following CAR T-cell therapy: Insights from the dutch “Follow that CAR!” registry 

Summary

These studies show that certain gene changes and treatments like CAR T-cell therapy can affect the risk of blood clots and bleeding in people with B-cell lymphomas. Talk with your lymphoma specialist about your personal risk so you can plan the safest monitoring and prevention steps for your care. 

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