Vaccine causes remission in patients with leukemia

AORN Journal,  Jan, 2005  

• E-mail
• Print
• Link

Researchers at The University of Texas M. D. Anderson Cancer Center, Houston, have found that vaccination with a peptide that is abnormally expressed on myeloid leukemia cells can produce a complete molecular remission in some patients, according to a Dec 7, 2004, news release from the university. The experimental vaccine produced an immune response in 60% of patients tested (ie, 20 of 33 patients able to be evaluated).

Almost all of the patients had either active or relapsed acute myelogenous leukemia or refractory chronic myelogenous leukemia--types of leukemia in which there is a dangerous accumulation of immature cells in the bone marrow. Others had high-risk myelodysplastic syndrome, a precancerous bone marrow disorder.

Of the 20 patients who exhibited an immune response against their cancer, 14 had an overall survival of four years. None of the 13 patients who had no immune response lived that long, according to researchers. Three patients are in molecular remission, in which there is no evidence of the disease remaining.

The vaccine is made from the PR1 peptide, part of a protein that is found inside leukemia cells. Vaccine delivery induces immune cells that recognize the PR1 peptide--which naturally exists in normal bone marrow cells--and draws them to the bone marrow that contains leukemia. The target protein is overexpressed on leukemia cells, so it directs immune T-cells to kill the leukemia and leave normal cells unaffected.

The vaccine appears to create an immune system "memory" for the PR1 peptide, resulting in long-term protection. Despite patients receiving the vaccine only three times, researchers measured an immune response in patients four years after treatment.

Peptide Vaccine Can Produce Complete Remission in Myeloid Leukemia Patients (news release, Houston: The University of Texas M. D. Anderson Cancer Center, Dec 7, 2004) http://www.mdanderson.org/departments/newsroom/display.cfm? id=D6A2C4F6-8745-11D5-813100508B603A14&method=displayFull&pn=00c8 a30f-c468-11d4-80fb00508b603a14 (accessed 9 Dec 2004).

COPYRIGHT 2005 Association of Operating Room Nurses, Inc.
COPYRIGHT 2005 Gale Group