Rationale and design of the 2 by 2 factorial design GnG-trial: a randomized phase-III study to compare two schedules of gemtuzumab ozogamicin as adjunct to intensive induction therapy and to compare double-blinded intensive postremission therapy with or without glasdegib in older patients with newly diagnosed AML.

BACKGROUND: Overall survival remains poor in older patients with acute myeloid leukemia (AML) with less than 10% being alive after 5 years. In recent studies, a significant improvement in event-free, relapse-free and overall survival was shown by adding gemtuzumab ozogamicin (GO), a humanized antibody-drug conjugate directed against CD33, to intensive induction therapy once or in a sequential dosing schedule. Glasdegib, the small-molecule inhibitor of smoothened (SMO), also showed improved overall survival in patients not eligible for intensive chemotherapy when combined with low-dose cytarabine compared to low-dose cytarabine alone. These findings warrant further investigations in the phase III GnG trial. METHODS/DESIGN: This is a randomized phase III trial with measurable residual disease (MRD) after induction therapy and event-free survival (EFS) as primary endpoints. The two research questions are addressed in a 2 by 2 factorial design. Patients age 60 years and older are upfront randomized 1:1 in one of the two induction arms: GO administered to intensive induction therapy on days 1,4, and 7 versus GO administered once on day 1 (GO-147 versus GO-1), and double-blinded 1:1 in one of the subsequent treatment arms glasdegib vs. placebo as adjunct to consolidation therapy and as single-agent maintenance therapy for six months. Chemotherapy backbone for induction therapy consists of standard 7 + 3 schedule with cytarabine 200 mg/m2 continuously days 1 to 7, daunorubicin 60 mg/m2 days 1, 2, and 3 and high-dose cytarabine (1 g/m2, bi-daily, days 1, 2, and 3) for consolidation therapy. Addressing two primary endpoints, MRD-negativity after induction therapy and event-free survival (EFS), 252 evaluable patients are needed to reject each of the two null hypotheses at a two-sided significance level of 2.5% with a power of at least 85%. ETHICS AND DISSEMINATION: Ethical approval and approvals from the local and federal competent authorities were granted. Trial results will be reported via peer-reviewed journals and presented at conferences and scientific meetings. TRIAL STATUS: Protocol version: 1st version 20.10.2020, no amendments yet. Study initiation on February 16, 2021. First patient was recruited on April 1st. TRIAL REGISTRATION: ClinicalTrials.gov NCT04093505 ; EudraCT 2019-003913-32. Registered on October 30, 2018.

Minimal residual disease detection in mantle cell lymphoma: methods and significance of four-color flow cytometry compared to consensus IGH-polymerase chain reaction at initial staging and for follow-up examinations.

BACKGROUND: The increasing application of multi-color flow cytometry assays for staging and follow-up in mantle cell lymphoma necessitates that the specificity and sensitivity of this technique are evaluated. Data from prospective clinical trials comparing the clinical applicability of flow cytometry to routine diagnostic methods and to polymerase chain reaction are currently lacking. DESIGN AND METHODS: We applied a standardized four-color flow cytometry assay to 281 prospectively collected peripheral blood and bone marrow samples from 98 patients with mantle cell lymphoma participating in a multi-center clinical trial and compared the results to those obtained with conventional clinical staging and consensus primer IGH-polymerase chain reaction. RESULTS: The maximum sensitivity of flow cytometry using light chain restriction in CD19+CD5+ subpopulations was 8.0 x 10(-4) while flow cytometry that relied on immunophenotypic aberrations was less sensitive (2.4 x 10(-3)). Mantle cell lymphoma cells were detected in 87.3% of 110 pre-treatment samples from 84 patients by flow cytometry and in 94.5% by polymerase chain reaction. Eight out of 84 patients (9.5%) diagnosed clinically as having stage II or III disease showed peripheral blood or bone marrow involvement according to flow cytometry, thus documenting more advanced disease. At follow-up residual lymphoma cells were detected by flow cytometry and concordantly by polymerase chain reaction in 10/171 samples (5.8%); however, 31 follow-up samples (18.1%) were positive for minimal residual disease according only to polymerase chain reaction analysis. CONCLUSIONS: The sensitivity of four-color flow cytometry is comparable to that of IGH-polymerase chain reaction at initial staging but is less sensitive at follow-up after immuno-chemotherapy. Both techniques are highly valuable methods for accurate initial staging.