Transplant Plus Personalized Vaccine Promising in Advanced CLL

Researchers from Dana-Farber Cancer Institute have reported on a successful trial involving patients with advanced chronic lymphocytic leukemia and a personalized tumor vaccine.

A personalized tumor vaccine is made of a patient's own inactivated leukemia cells combined with GM-CSF (an immune response stimulator). In this study, the vaccine was given to patients after they underwent an allogeneic stem cell transplant, with the theory that the vaccine would strengthen the so-called "graft-vs-leukemia effect" in CLL patients. In other words, the vaccine would make the transplant more effective against the cancer (the "graft" being the donated marrow).

This was a phase I trial that enrolled 22 patients diagnosed with advanced and aggressive CLL. Thirteen patients had bone marrow involvement.

Four patients were unable to participate because they developed graft-vs-host disease (GVHD) following transplant. In GVHD, the "graft" attacks the patient. This is often a fatal development.

The other 18 patients received at least one dose of the vaccine, although seven of them had to stop receiving it when they developed GVHD.

After a median follow-up of 2.9 years:

• Thirteen patients had remained in continuous complete remission;
• One patient had stable disease;
• Three patients developed progressive disease and two of them had died.

Being a phase I trial, this was designed to test not for efficacy but for the safety and biologic activity of what they call "whole tumor-cell vaccination." Researchers believe the results warrant further studies into therapeutic vaccines following bone marrow transplants in these patients.

Their findings appeared in the Journal of Clinical Investigation.

Source: J Clin Invest