U.S. scientists say patients responding to a new peptide vaccine for leukemia enjoyed a median remission more than three times longer than non-responders.
Researchers at the University of Texas M. D. Anderson Cancer Center said immune response to the PR1 vaccine was associated with an 8.7-month event-free survival compared with 2.4 months for non-responders. Clinical responses ranging from improvements in blood counts to complete cytogenetic remission.
"We did not expect dramatic responses in this clinical trial, and were pleasantly surprised to see the clinical responses and improved event-free survival" said Dr. Muzaffar Qazilbash, an associate professor in the department of stem cell transplantation and cellular therapy.
The Phase I/II clinical trial was designed to assess the vaccine's safety and ability to elicit an immune response. Toxicity was limited to low-grade injection site side effects such as redness, swelling and some pain.
Disease-specific Phase II clinical trials of the vaccine for chronic myelogenous leukemia and myelodysplastic syndrome are planned or are under way and the company that makes the vaccine is conducting a national Phase III clinical trial for acute myelogenous leukemia.
The findings were reported in Atlanta during the annual meeting of the American Society of Hematology.
Copyright 2007 by United Press International
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