Livia, Here is the summary report on the Phase I clinical trial of this vaccine you are considering: http://meeting.jco.org/cgi/content/abstract/24/18_suppl/6509?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=vaccine+cml&searchid=1&FIRSTINDEX=0&volume=24&issue=18_suppl&resourcetype=HWCIT
K562/GM-CSF vaccination reduces tumor burden, including achieving molecular remissions, in chronic myeloid leukemia (CML) patients (PTS) with residual disease on imatinib mesylate (IM) B. Smith, Y. L. Kasamon, C. B. Miller, C. Chia, C. Gocke, J. Kowalski, I. Tartakovsky, B. Biedrzycki, R. J. Jones, K. Hege and H. I. Levitsky Johns Hopkins University, Baltimore, MD; Cell Genesys, Inc., South San Francisco, CA Background: Despite high rates of clinical responses to IM, molecular complete responses are rare. The curative potential of allo transplantation and donor lymphocyte infusions underscores CML's responsiveness to T cell mediated immunity. K562/GM-CSF is a tumor vaccine derived from a CML cell line that expresses several defined CML associated antigens and has been genetically engineered to produce GM-CSF. A pilot vaccination strategy was developed to determine if K562/GM-CSF immunotherapy in combination with IM could enhance T cell reactivity and clinical responses in pts having persistent, measurable disease despite 1 or more years on IM. Methods: Eligibility required pts to have achieved a major cytogenetic response (<35% Ph+ cells) while on a stable dose of IM. Disease burden was measured serially over 12 wks prior to vaccines. 4 vaccines were administered in 3 wk intervals, each consisting of 1 x 108 irradiated K562/GM-CSF cells distributed over 10 sites, with or without topical 5% Aldara (a Toll- like receptor 7 agonist) used as a vaccine adjuvant. Disease burden was measured at 6 wk intervals for 9 mos from the first vaccine and specimens were banked for measurement of immune responses. Results: The trial enrolled 19 pts, all have completed the planned 4 vaccinations and 14 pts have completed all planned disease burden measurements. The median age is 52 (range 28-76) yrs with a median time from dx to enrollment of 57 (range 16-111) mos. Pts were on IM for a median of 37 (13-53) mos prior. 4 of 19 pts had FISH pos as their best previous response (BPR) with 2 becoming FISH neg post- vaccine (1 became PCR neg and 1 achieved a >1 log reduction in disease burden by PCR). Of the 15 pts whose BPR was FISH neg/PCR pos, 4 are now PCR neg post vaccine, 4 experienced a >1 log and 1 had 0.5-0.99 log reduction by PCR. Mean PCR levels for the 19 pts declined btwn pre- and post-vaccine measures (p=0.01). 3 of 5 pts achieving PCR neg remain so beyond 6 months. Only 1 pt progressed having entered the study with a heavy disease burden (30% FISH pos). Conclusions: K562/GM- CSF vaccine appears to improve responses in pts on IM, including achieving complete molecular remissions, despite long durations of previous IM therapy. END QUOTE The vaccine in the clinical trial you are considering is made by taking the patient's own leukemic cells, mixing them with GM-CSF (Leukine -- which boosts WBC production), and then the mixture is irradiated to geneticly alter the cells. The goal is to try to teach the patient's T-cells to recognize the altered leukemic cells as something that should be attacked and eliminated, and also teach those same T-cells to attack live leukemic cells. The Phase I report above shows that it works to some degree on some people, but not on everyone. I participated in a different type of vaccine clinical trial earlier this year and will post some information about it in the near future. But as far as whether you should participate and why you would want to, you need to look into several issues. First, your Onc is also involved in the clinical trial, so he needs to get 54 people to sign up for it, which is harder than you might think. He may not have any other reason for suggesting that you participate but to fill his quota, so you should ask him that directly. If your RT-PCRs are negative but the lab has also been doing nested Q-PCRs which are more sensitive and show positive, then you have at least a 4 or 5 log reduction in BCR-ABL. So controlling the disease is not much of an issue for you. So the reasons to participate in the trial could be: 1) to help expand the science of CML vaccines, 2) to see if you are able to further reduce your BCR-ABL levels, and have the residual effects carry you during pregnancy, 3) to hope the vaccine might eliminate some or all of your leukemic stem cells and progenitor cells that Gleevec cannot eliminate, and become cured (this is not proven, and is highly questionable). There is another item, which is that you may not be accepted into the trial since your BCR-ABL levels are so low. The clinical trials prefer to have people with only a 2 log reduction, so they can track the progress in BCR-ABL reduction. If you go from being barely detectable to undetectable, have they learned anything about the vaccine, or was it just chance? Overall, it is a very personal decision, and the most likely outcome is that you will simply help advance the science of CML vaccines. --~--~---------~--~----~------------~-------~--~----~ [CMLHope] A support group of http://cmlhope.com ------------------------------------------------- You received this message because you are subscribed to the Google Groups "CMLHope" group. To post to this group, send email to CMLHope@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/CMLHope -~----------~----~----~----~------~----~------~--~---
