Session: 613. Acute Myeloid Leukemia: Clinical Studies: Poster I
Hematology Disease Topics & Pathways:
Diseases, AML, Adult, Study Population, Myeloid Malignancies
Methods: Patients aged 18+ in the UK NCRI AML15,16,17 trials were identified who harboured a FLT3 ITD mutation, were treated with intensive chemotherapy, and were either refractory to two courses of induction therapy, or relapsed within six months of transplant, or did not receive a prior transplant and had a remission duration of 6 months or less. Patients were grouped hierarchically as refractory, relapsed post transplant, or relapsed without prior transplant. Eligibility was established at the point a patient first became eligible for analysis. The primary outcome was overall survival (OS), measured from point of eligibility, with subsequent remission with or without count recovery as secondary outcome. A sensitivity analysis was performed excluding those who died within 21 days of eligibility to eliminate patients who might be thought of as too unwell to enter a post-relapse trial. Cox regression was used to identify prognostic factors for survival.
Results: A total of 264 patients were identified (refractory n=58, relapsed post SCT n=49, relapsed without SCT n=157). The median age was 51 (range 18-84); 25% of patients were aged 60 or older; 44% were male, 95% had intermediate cytogenetics; 11% had secondary disease. Split by age, among those under 60 45 were refractory, 44 relapsed post SCT and 110 relapsed without SCT; for ages 60+ the figures were 13 vs 5 vs 47. Overall 17% of patients experienced a subsequent remission; with median survival of 86 days and 1 year OS of 13%. If deaths within 21 days were excluded, the remission rate improved to 21%; with a median survival of 133 days and 1 year OS of 16%.
In multivariable Cox regression, age group HR for age>60 1.81 (1.33-2.47) p=0.0002) and route to eligibility (HR refractory vs relapsed no SCT 0.77 (0.55-1.07); relapsed post SCT vs no SCT 1.58 (1.11-2.25) p=0.003) were the only factors affecting survival – in particular sex, secondary disease, and ITD allelic burden were not significant. In the sensitivity analyses, only age was significant (HR 1.77 (1.24-2.53) p=0.001); with route to eligibility not significant (p=0.14).
Among patients with post-relapse treatment information, 65% were treated intensively, 8% non-intensively, and 20% with palliation – other patients received experimental therapies. When restricting attention to those treated intensively, median survival was 130 days with 17% 1 year OS. Figures were not materially changed if early death was excluded.
Of 215 patients who had not relapsed post transplant, 53 (25%) received a transplant post-eligibility. In these 56 patients, median survival was 301 days with 42% alive at one year.
Conclusions: In relapsed/refractory AML, outcomes for FLT3-ITD mutated patients are generally poor and worse for older patients. Applying the eligibility criteria of QUANTUM-R and excluding early deaths gives outcomes comparable to the control group of the QUANTUM-R study. In the 25% of patients who proceeded to transplant survival was extended indicating that a treatment which can deliver patients to transplant has the potential to improve patient outcomes.
Disclosures: Hills: Daiichi Sankyo: Consultancy, Honoraria. Russell: Daiichi Sankyo: Consultancy; Pfizer: Consultancy, Honoraria, Speakers Bureau; Jazz Pharma: Speakers Bureau.
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