ATLANTA, Dec. 9 /PRNewswire-USNewswire/ -- Six studies that highlight important advances in the treatment of leukemia, including acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic-phase chronic myelogenous leukemia (CML), will be presented today at the 49th Annual Meeting of the American Society of Hematology (ASH) in Atlanta, GA. A press conference revealing this new research will take place on Sunday, December 9, from 9:30 a.m. to 10:30 a.m.
"Every year scientists are continually making advances in learning more about what causes normal bone marrow cells to become cancerous on the genetic level," said Richard A. Larson, MD, University of Chicago, Chicago, IL, and moderator of the leukemia press conference. "Through this cutting-edge research, we are finding more effective combination therapies and developing new targeted cancer agents that help extend the lives of our patients with leukemia. Research presented at this year's meeting focuses on many of these innovative treatment advances."
-- Preliminary results from a phase III study of interleukin-2 immunotherapy in young and middle-aged adults with acute myeloid leukemia [Abstract #157]
Jonathan E. Kolitz, MD, Monter Cancer Center, Lake Success, NY
This phase III study, conducted by the Cancer and Leukemia Group B, assessed the possible benefit of immunotherapy with rIL-2 (recombinant interleukin-2) in patients with AML in complete remission who had completed all planned therapy but were at risk of relapse.
A total of 734 patients were randomized into two induction regimens: Ara-C, daunorubicin and etoposide chemotherapy plus PSC-833, a P-glycoprotein modulator, or chemotherapy alone. Post-remission therapy was based on cytogenetic risk factors - patients with core binding factor(CBF) AML received three courses of high-dose Ara-C chemotherapy, while all others were assigned to receive a two-step autologous transplant regimen. Randomization between the rIL-2 and observation arms was to occur no later than 120 days after the first day of the last high-dose Ara-C cycle or day zero of the autologous transplant.
To date, the three-year disease-free survival rate has reached 56 percent in the rIL-2 arm compared to 45 percent in the observation arm. Additionally, the three-year overall survival rate reached 68 percent for those treated with rIL-2 compared to 61 percent in the observation group. Since the current standard is to offer no further therapy, the fact that this therapy can be given safely to outpatients is an important advance in care.
-- Improved event-free survival seen with PR1 peptide vaccine in patients with various forms of myeloid leukemia [Abstract #283]
Muzaffar H. Qazilbash, MD, The University of Texas M. D. Anderson Cancer Center, Houston, TX
This randomized phase I/II trial evaluated the safety and efficacy of a PR1 peptide vaccine in contributing to complete cytogenetic remission, which is determined through genetic and chromosomal analysis of the bone marrow, in patients with various forms of myeloid leukemia. It is the largest vaccine trial in leukemia patients to date, in which a vaccine was given without concurrent anti-leukemia chemotherapy and showed durable clinical responses in high-risk patients who had failed several prior therapies.
Sixty-six patients with AML, CML, or myelodysplastic syndrome were treated with PR1 peptide vaccine. Fifty-four patients received three vaccinations and 12 patients received six vaccinations. The study found that the vaccine was well tolerated, with toxicity limited to grade I and II injection-site reactions. Among the 53 patients with active disease at vaccination, PR1 vaccine-induced immune response was seen in 47 percent of patients. Clinical responses were observed in 36 percent of immune responders vs. 10 percent of immune non-responders.
The PR1 vaccine-induced immune response was associated with a longer eventâfree survival, 8.7 months vs. 2.4 months, and a trend toward longer overall survival. This is the first trial that showed a longer event-free survival in patients who demonstrated an immune response to the vaccine. Among 13 patients treated in complete remission, four have remained in remission for a median of 30.5 months.
