Petra Muus

Summary The most effective post-remission treatment to maintain complete remission (CR) in adults aged between 46 and 60 years with acute myeloid leukaemia (AML) is uncertain. Previously untreated patients with AML in CR after induction chemotherapy with daunorubicin and cytarabine were randomized between two intensive courses of consolidation therapy containing high-dose cytarabine, combined with amsacrine or daunorubicin and a standard consolidation and maintenance therapy containing standard dose cytarabine and daunorubicin. One hundred fifty-eight CR patients were assigned to the intensive group and 157 patients to the standard group. After a median follow-up of 7.5 years, the 4-year survival rate was 32 % in the intensive group versus 34 % in the standard group (P = 0.29). In the intensive group, the 4-year relapse incidence was lower than in the standard group: 55 and 75 %, respectively (P = 0.0003), whereas treatment-related mortality incidence was higher: 22 versus 3 % (P < 0.0001). Two intensive consolidation courses containing high-dose cytarabine as post-remission treatment in patients with AML aged between 46 and 60 years old did not translate in better long-term outcome despite a 20 % lower relapse incidence. Better supportive care and prevention of treatment-related complications may improve the overall survival after intensified post-remission therapy in this age group.

Acute myeloid leukemia (AML) in the elderly is associated with low rates of response to conventional chemotherapy and long-term survival, highlighting the need for innovative treatment strategies. Gemtuzumab ozogamicin (GO) is an immunoconjugate that has shown activity in relapsed AML with a favorable safety profile. The aim of this collaborative trial was to assess the feasibility, safety, and antileukemic activity of administering GO followed by conventional chemotherapy as first line therapy in patients aged 61-75 years with AML. Eligible patients received frontline treatment with GO 9 mg/m2 infused intravenously on days 1 and 15. Following response assessment to GO, patients were started on conventional chemotherapy consisting of the MICE regimen (mitoxantrone, cytarabine, etoposide). No further treatment was planned for complete responders. Among the 57 evaluable patients, 38 (67%) completed the entire sequential treatment as planned. The overall response rate to the entire induction sequence was 54.4% (31/57), with complete remission (CR) in 35.1% and complete remission with incomplete platelet recovery (CRp) in 19.3%. Rates of failure due to treatment-related mortality or resistant disease were 14.1% (3 toxic deaths during the GO segment, 5 during MICE) and 29.9%, respectively. An initial response to GO was documented in 20 patients (35.1%), with CR in 22.8% and CRp in 12.3%; 6 additional patients entered a partial remission. Reversible myelosuppression and liver toxicity were the main adverse events during both segments of induction. Frontline GO was associated with modest mucosal and gastrointestinal toxicity, but grade 3-4 pancytopenia was universal and prolonged. Hepatic veno-occlusive disease developed in 3 patients after GO and 2 after MICE, resulting in 4 deaths from liver failure. One-year survival at follow-up was 34%. Twelve patients continue in CR/CRp after a median of 226 days. The sequential combination of GO and conventional chemotherapy is a feasible and active treatment strategy for older patients with untreated AML. This novel regimen is now being compared in a phase III trial (AML-17).

In the EORTC ALL-3 trial, the efficacy of allogeneic transplantation was compared with that of autologous marrow transplantation and maintenance chemotherapy in patients <or= 50 years who reached CR. Among 340 patients who entered the study, 279 were <or=50 years old. Out of these, 220 reached CR, 184 patients started consolidation and were HLA typed; 68 had a donor and 116 had no sibling donor. The median follow-up was 9.5 years; 93 patients relapsed, 26 died in CR, and overall 116 patients died. Allogeneic transplantation was performed in 47 (68%) patients with a donor while autologous transplantation or maintenance chemotherapy was given to 84 (72%) patients without a sibling donor. The 6-year disease-free survival rate was similar in the groups with and without donor [38.2% (SE=5.9%) vs. 36.8% (SE=4.6%), hazard ratio 1.01, 95% CI 0.67-1.53]. Comparing the donor group with the no donor group, the former had a lower relapse incidence (38.2% vs. 56.3%, p=0.001), but a higher cumulative incidence of death in CR (23.5% vs. 6.9%, p=0.0004). The 6-year survival rates were similar [41.2% (SE=6.0%) vs. 38.8% (SE=4.6%)]. This trial did not show that allogeneic transplantation, when a sibling donor is available, produces a better outcome than the policy of offering autotransplantation or chemotherapy in the absence of a donor.