German drug developer Affimed NV put on hold two early stage clinical studies testing an investigational immunotherapy to treat blood cancer following the death of one of the patients and other life-threatening events.

The immunotherapy AFM11, a CD19/CD3-targeting T cell engager, is being evaluated to treat CD19 positive B cell non-Hodgkin lymphoma, or NHL, in patients whose cancer came back or was unresponsive to treatment. The immunotherapy is also being tested on patients with acute lymphoblastic leukemia, or ALL.

Affimed said in its Oct. 8 press release that a patient in the ALL study died and two life-threatening events occurred in the NHL study. These adverse events happened in the highest dose arms of both studies, the company added. The two studies enrolled 33 patients.

Non-Hodgkin's lymphoma is a group of blood cancers that originate in the lymphatic system, an important part of the immune system. Patients with non-Hodgkin's lymphoma develop tumors in white blood cells known as lymphocytes.

Heidelberg, Germany-based Affimed plans to release an update for the future plans of its AFM11 program after conducting a review of the study with global health authorities, the Safety Monitoring Committees and the clinical investigators of the studies.

Affimed has another immunotherapy in development — AFM13 — which helped to reduce cancer in an early stage trial of the drug in combination with Merck & Co. Inc.'s Keytruda. The German biopharmaceutical company in August signed a collaboration deal with Swiss drugmaker Roche Holding AG to develop cancer treatments.