Dear Tracey,
You can find details of the French study that you are referring to under the 'newswire'... scroll down to Dec.19.
I have copied part of the summary presented at ASH 2008 below Hope this clarifies some of the numbers etc.
Note that previous IFN treatment was not considered to be statistically relevant to the overall outcomes.
Also note that all patients who relapsed regained sensitivity and responded when IM was reintroduced.
There are other studies ongoing...
Sandy
Capsule Summary
CCO Independent Conference Coverage of the American Society of Hematology 2008 Annual Meeting*
*CCO is an independent medical education company that provides state-of-the-art medical information to healthcare professionals through conference coverage and other educational programs.
STIM Study Shows CML Complete Molecular Remission Possible to Maintain Following Imatinib Discontinuation
Posting Date: December 13, 2008
* Stop Imatinib (STIM) study: a prospective, multicenter study[1]
Summary of Key Conclusions
* Complete molecular remission maintained in a substantial proportion of individuals with CML following imatinib discontinuation, particularly those pretreated with interferon
o Trend toward greater likelihood of sustained molecular remission in interferon-treated group not statistically significant
o Authors conclude that imatinib discontinuation feasible following sustained complete molecular remission, even among patients treated with imatinib monotherapy
* Longer follow-up with larger number of patients needed to identify factors that influence durability of complete molecular remission
Background
* Imatinib
o Effective treatment for CML
o Treatment continues for indefinite time period
o Unclear whether imatinib can eliminate oncogenic CML clone, potentially allowing for discontinuation of treatment
* Pilot study assessed imatinib discontinuation in patients with CML[2]
o 15 patients in molecular remission for > 2 years on imatinib followed
o 7 patients had molecular relapse during median follow-up of 38 months
o 8 patients maintained complete molecular remission
+ Many of these patients treated with interferon prior to receipt of imatinib
o Median molecular relapse-free survival : 6 months
* Current study assessed persistence of complete molecular remission in a larger cohort of CML patients discontinuing imatinib
Summary of Study Design
* Patients enrolled at 22 centers in France beginning in July 2007
* Inclusion criteria
o ? 18 years of age
o Complete molecular remission for ? 2 years during imatinib treatment
o Molecular monitoring in accord with international guidelines
* Exclusion criteria
o Receipt of confounding treatment (corticosteroids, immunosuppressive therapy, chemotherapy, radiotherapy)
* Primary objective
o Persistence of complete molecular remission
* Secondary objectives
o Clinical and biological factors influencing persistence of complete molecular remission
o Duration of complete molecular remission
o Molecular relapse rate following 6 months of complete molecular remission without imatinib
o Economic effect of imatinib cessation
* Patients with molecular relapse, defined as positivity on quantitative real-time polymerase chain reaction, retreated with imatinib 400 mg/day
o Had to confirm molecular relapse at 2 consecutive assessments
Baseline Characteristics
* Total of 69 patients enrolled in study
* Baseline characteristics for 60 patients with > 1 month of follow-up data
o Median age: 62 years (range: 29-80)
o Female: 38 (63%)
o Previous treatment with interferon: 31 (52%)
o Median patient follow-up: 5 months (range: 1-16)
Main Findings
* Molecular relapse occurred in 28 patients (41%)
o Most cases of relapse observed during first 6 months off of imatinib
o 7 patients have reached Month 14 off of imatinib and have maintained complete molecular remission
+ 5 of these 7 patients received treatment with interferon prior to imatinib
o 1 patient has reached Month 16 off of imatinib without molecular relapse
* Among 27 patients who relapsed during first 6 months off of imatinib
o 13 received previous treatment with interferon
o 14 treated with imatinib only
* Overall, probability of maintaining complete molecular remission at Month 9 off of imatinib: 46% (95% CI: 32% to 59%)
o Probability slightly better for patients who received treatment with interferon before imatinib vs those who received imatinib de novo, but not statistically significant (P = .54)
+ Previous treatment with interferon before imatinib: 53% (95% CI: 33% to 69%)
+ De novo treatment with imatinib: 39% (95% CI: 20% to 58%)
* All patients with molecular relapse who reinitiated imatinib treatment still sensitive to imatinib rechallenge
References
1. Mahon FX, Huguet F, Guilhot F, et al. Is it possible to stop imatinib in patients with chronic myeloid leukemia? An update from a French pilot study and first results from the multicentre “Stop Imatinib” (STIM) study. Program and abstracts of the 50th American Society of Hematology Annual Meeting and Exposition; December 6-9, 2008; San Francisco, California. Abstract 187.
2. Rousselot P, Huguet F, Rea D, et al. Imatinib mesylate discontinuation in patients with chronic myelogenous leukemia in complete molecular remission for more than 2 years. Blood. 2007;109:58-60.
©2008 Clinical Care Options, LLC.
May be copied for personal use only. To request permission for other use, contact at permissions@clinicaloptions.com .
Sandy
