ATLANTA (FRONTLINE MEDICAL NEWS) Minimal residual disease-guided treatment with azacitidine is an effective strategy for preventing or delaying hematological relapse in patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) who are at high risk for relapse, according to findings from the open-label, interventional RELAZA2 trial .

Of 205 patients screened between 2011 and 2015 at 11 centers in Germany, 53 became minimal residual disease (MRD) positive while remaining in hematological remission. All 53 started azacitidine-based preemptive treatment, and 6 months after the initiation of the MRD-guided therapy, 31 (58%) were still in complete remission, while 22 (42%) relapsed after a median of three treatment cycles, Uwe Platzbecker, MD, reported at the annual meeting of the American Society of Hematology.

Of those still in complete remission, 21 patients responded with a decline of MRD below a predefined threshold, and 10 achieved stabilization in the absence of relapse, said Dr. Platzbecker of the University Hospital Carl Gustav Carus Dresden, Germany.

The overall response rate was greater in those who underwent allogeneic hematopoietic stem cell transplantation (71% vs. 48%), he noted.

“After 6 months, 24 patients continued to receive a median of nine subsequent azacitidine cycles. Seven patients completed 24 months of treatment according to protocol. Eventually, hematologic relapse occurred in eight of those patients (33%) but was delayed until a median of 397 days after initial MRD detection,” he said in an interview, adding that, overall, 26 of the 53 patients in the study (49%) experienced hematologic relapse, which was delayed until a median of 422 days after initial MRD detection.

Study subjects were adults with a median age of 59 years with measurable MRD suggestive of imminent relapse but who were still in CR. Most (48) had AML, and 5 had MDS. They were treated preemptively with six cycles of 75 mg/m2 of azacitidine given subcutaneously on days 1-7 of each 1-month cycle. Those who continued treatment beyond the initial 6 months were treated with risk-adapted azacitidine-based therapy for up to 18 additional months.

Treatment was well tolerated. Grade 3 or 4 thrombocytopenia occurred in three patients, and grade 3 or 4 neutropenia occurred in 45 patients. Infections and pneumonia, which occurred in four and three patients, respectively, were the main serious side effects during the first 6 cycles.

“With a median follow-up of 13 months after the start of MRD-guided preemptive treatment, the actual overall and progression free survival rate was 76% and 42%, respectively,” Dr. Platzbecker said.

Chemotherapy frequently results in complete remission in patients with MDS or AML, but a substantial proportion of patients relapse even after allogeneic stem cell transplantation, he said, noting that treatment options in these patients are limited.

In the prospective RELAZA 1 trial, short-term preemptive azacitidine therapy was associated with sustained responses. RELAZA2 was designed to assess the ability of early nonintensive azacitidine treatment, directed by MRD monitoring after allogeneic stem cell transplantation and chemotherapy, prior to avert relapse.

The findings suggest that this approach is effective in patients at higher risk of relapse, but the success of treatment seems to be context dependent, Dr. Platzbecker said, explaining that this finding emphasizes the potential immunomodulatory role of hypomethylating agents.

“The study supports the prognostic importance of MRD in AML and may serve as a platform for future studies in combining hypomethylating agents and novel targeted therapies,” he concluded.

The RELAZA2 trial is sponsored by Technische Universität Dresden. Dr. Platzbecker reported serving as a consultant for, and receiving honoraria and research funding from Celgene, Janssen, Novartis, and Acceleron.

SOURCE: Platzbecker U et al. ASH 2017 Abstract #565 .