Blinatumomab is safe and effective in relapsed and MRD-positive B-ALL CD19+ patients: The Bologna Compassionate Program Experience.

Abstract

e18522 Background: Adult B-ALL patients still have a dismal prognosis, due to a high incidence of relapse even after allogenic SCT. Safety and efficacy of Blinatumomab, anti CD3-CD19 Bite antibody, has been demonstrated both in MRD pos patients and in relapsed/refractory (R/R) setting. To evaluate safety profile and efficacy of Blinatumomab, obtained through a compassionate use, in a cohort of 18 adult patients affected by MRD+ or R/R B-ALL treated at Bologna University. Methods: From March 2015 to December 2017, 18 patients received Blinatumomab at the standard dosage (9 mcg/d x 7 days, 28 mcg/d x 21 days) in 28-days courses. All the patients were hospitalized to receive the 1st course of therapy. The following courses, based on the good safety profile of the compound, were administered in outpatient setting. 18 patients (M/F = 10/8; median age 43, r. 18-73) have been treated. Ph chromosome was detected in 8/18 . 10 were MRD+ (5 Ph pos and 5 Ph neg); E2A-PBX1 and MLL-AF4 rearrangements were found in two patients. 8 patients had a R/R disease (3 Ph pos/5 Ph neg). Median WBC count before starting therapy with Blinatumomab was 5400/mmc (r. 500-76500). All patients had previously received many lines of therapy (median 4, r. 1-7). In 4 cases an alloTMO was already performed, and two patients had received two transplants. 12/18 patients were referred to us by other Institutions. All the patients received at least one course of Blinatumomab. Bone marrow evaluations, including cytogenetics, molecular biology and immunophenotyping analysis were performed at the beginning of every course of therapy in order to assess patients' disease status. MRD evaluation was assessed through BCR-ABL fusion transcript quantitative analysis in Ph pos ALL patients and Ig rearrangment in Ph neg patients. Monitoring of adverse events was periodically performed. 16/18 patients are evaluable for response, at least to one cycle. Results: 9/16 (56%) patients obtained a CR (7/9 MRD+ and 2/7 R/R). In 7/9 (78%) responders patients a molecular CR was reached, (in 6 patients after the first course, in one case after the second one). 5 responders proceeded to alloBMT and are actually alive in CR (median follow-up after transplant 240 days). In terms of toxicity, one patient developed a grade IV neurological event (mental confusion, tremor), which completely resolved after a transient drug withdrawal. Conclusions: Our results confirm the high rate of response and to Blinatumomab in a poor patients' population, and the good management profile of the compound.