A Clinical Trial Of Antigen-Pulsed Dendritic Cells (DC) In The Treatment Of Patients With B-Cell Lymphoma
Researchers at Stanford University Medical Center presented preliminary results of a study on a new vaccine treatment for B-cell lymphoma.
Chemotherapy and/or radiation can cause remission in most patients with B-cell lymphoma. However, despite responsiveness to treatment, patients ultimately relapse and most cannot be cured with standard treatment. One new approach to treatment evokes the immune system's ability to target and eliminate cancerous cells while sparing normal cells. B-cell malignancies present an opportunity to use the immune system because a tumor specific "marker" has been identified. This marker (termed idiotype or Id) resides on the surface of the B-cells. Each tumor displays many copies of a single idiotype which is different for each patient.
Previous studies have shown that the immune system can kill B-cell lymphomas by recognizing the idiotype on the surface of the tumor cell. Lymphoma patients who had received a custom made tumor idiotype vaccine developed anti-tumor immunity.
In the current study, Frank Hsu, M.D., clinical and research fellow, division of oncology, and colleagues immunized 8 patients with residual B-cell lymphomas previously treated with chemotherapy. In a two-day process, dendritic cells (DCs) were harvested from each patients' blood, and allowed to mature in culture bathed n a solution containing the tumor idiotype. DCs are powerful antigen presenting cells, capable of engulfing proteins and working on the cells of the immune system to recognize and attack cells displaying those proteins on the surface of the cell. The purified, "antigen primed" DCs were then given intravenously to each patient. Anti-tumor immune responses have been detected in all six evaluable patients. Two patients experienced complete tumor regression and have remained in remission; one patient has been in remission for over two and half years, a second patient for over one year. Another patient had a mixed response with partial tumor regression. Patients did not experience significant side effects.
"These are very interesting data," noted Ellin Berman, M.D., associate professor, Memorial Sloan-Kettering Cancer Center (New York, NY) at a press briefing today. "Antigen pulsed DC can be used as a potent vaccine that induces significant responses."