Ex vivo venetoclax sensitivity testing predicts treatment response in acute myeloid leukemia.

The BCL-2 inhibitor venetoclax has revolutionized the treatment of acute myeloid leukemia (AML) in patients not benefiting from intensive chemotherapy. Nevertheless, treatment failure remains a challenge, and predictive markers are needed, particularly for relapsed or refractory AML. Ex vivo drug sensitivity testing may correlate with outcomes, but its prospective predictive value remains unexplored. Here we report the results of the first stage of the prospective phase II VenEx trial evaluating the utility and predictiveness of venetoclax sensitivity testing using different cell culture conditions and cell viability assays in patients receiving venetoclax-azacitidine. Participants with de novo AML ineligible for intensive chemotherapy, relapsed or refractory AML, or secondary AML were included. The primary endpoint was the treatment response in participants showing ex vivo sensitivity and the key secondary endpoints were the correlation of sensitivity with responses and survival. Venetoclax sensitivity testing was successful in 38/39 participants. Experimental conditions significantly influenced the predictive accuracy. Blast-specific venetoclax sensitivity measured in conditioned medium most accurately correlated with treatment outcomes; 88% of sensitive participants achieved a treatment response. The median survival was significantly longer for participants who were ex vivo-sensitive to venetoclax (14.6 months for venetoclax-sensitive patients vs. 3.5 for venetoclax-insensitive patients, P<0.001). This analysis illustrates the feasibility of integrating drug-response profiling into clinical practice and demonstrates excellent predictivity. This trial is registered with ClinicalTrials.gov identifier: NCT04267081.

Efficacy of conventional-dose cytarabine, idarubicin and thioguanine versus intermediate-dose cytarabine and idarubicin in the induction treatment of acute myeloid leukemia: Long-term results of the prospective randomized nationwide AML-2003 study by the Finnish Leukemia Group.

OBJECTIVES: AML-2003 study sought to compare the long-term efficacy and safety of IAT and IdAraC-Ida in induction chemotherapy of acute myeloid leukemia (AML) and introduce the results of an integrated genetic and clinical risk classification guided treatment strategy. METHODS: Patients were randomized to receive either IAT or IdAraC-Ida as the first induction treatment. Intensified postremission strategies were employed based on measurable residual disease (MRD) and risk classification. Structured questionnaire forms were used to gather data prospectively. RESULTS: A total of 356 AML patients with a median age of 53 years participated in the study. Long-term overall survival (OS) and relapse-free survival (RFS) were both 49% at 10 years. The median follow-up was 114 months. No significant difference in remission rate, OS or RFS was observed between the two induction treatments. Risk classification according to the protocol, MRD after the first and the last consolidation treatment affected the OS and RFS significantly (p < .001). CONCLUSIONS: Intensified cytarabine dose in the first induction treatment was not better than IAT in patients with AML. Intensification of postremission treatment in patients with clinical risk factors or MRD seems reasonable, but randomized controlled studies are warranted in the future.

Engraftment and outcome after autologous stem cell transplantation in plerixafor-mobilized non-Hodgkin's lymphoma patients.

BACKGROUND: Plerixafor is used in combination with granulocyte-colony-stimulating factor to enhance the mobilization of hematopoietic stem cells. Limited data are available in regard to effects of plerixafor on posttransplant outcomes in chemomobilized patients who appear to mobilize poorly. STUDY DESIGN AND METHODS: Eighty-nine chemomobilized patients with non-Hodgkin's lymphoma (NHL) were included in this retrospective study. Thirty-three patients had received plerixafor preemptively (plerixafor group) and 56 patients served as controls. Posttransplantation outcomes including infections, hematologic recovery, and relapse were recorded. RESULTS: The median fold increase of CD34+ cells after the first plerixafor dose was 4.1 in patients mobilized with chemotherapy plus filgrastim and 7.2 in those mobilized with chemotherapy plus pegfilgrastim (p = 0.027). The median number of collected CD34+ cells was 3.5 × 10(6) CD34+ cells/kg in the plerixafor group and 4.2 × 10(6) CD34+ cells/kg in the control group (p = 0.076). Early engraftment was comparable between the groups (10 days for neutrophils >0.5 × 10(9) /L and 14 days for platelets >20 × 10(9) /L, respectively). Also late engraftment within 12 months was comparable except higher hemoglobin level at 3 months in the control group (121 g/L vs. 112 g/L, p = 0.009). Progression-free survival at 1 year after autologous stem cell transplantation (ASCT) was 79% in the plerixafor group and 86% in the control group (p = 0.399). CONCLUSIONS: Long-term engraftment and outcome after ASCT seem to be comparable in NHL patients receiving plerixafor compared to chemomobilized patients. These observations support the use of plerixafor in patients who mobilize poorly.

Dasatinib crosses the blood-brain barrier and is an efficient therapy for central nervous system Philadelphia chromosome-positive leukemia.

Although imatinib, a BCR-ABL tyrosine kinase inhibitor, is used to treat acute Philadelphia chromosome-positive (Ph(+)) leukemia, it does not prevent central nervous system (CNS) relapses resulting from poor drug penetration through the blood-brain barrier. Imatinib and dasa-tinib (a dual-specific SRC/BCR-ABL kinase inhibitor) were compared in a preclinical mouse model of intracranial Ph(+) leukemia. Clinical dasatinib treatment in patients with CNS Ph(+) leukemia was assessed. In preclinical studies, dasatinib increased survival, whereas imatinib failed to inhibit intracranial tumor growth. Stabilization and regression of CNS disease were achieved with continued dasa-tinib administration. The drug also demonstrated substantial activity in 11 adult and pediatric patients with CNS Ph(+) leukemia. Eleven evaluable patients had clinically significant, long-lasting responses, which were complete in 7 patients. In 3 additional patients, isolated CNS relapse occurred during dasatinib therapy; and in 2 of them, it was caused by expansion of a BCR-ABL-mutated dasatinib-resistant clone, implying selection pressure exerted by the compound in the CNS. Dasatinib has promising therapeutic potential in managing intracranial leukemic disease and substantial clinical activity in patients who experience CNS relapse while on imatinib therapy. This study is registered at ClinicalTrials.gov as CA180006 (#NCT00108719) and CA180015 (#NCT00110097).

Prolonged immunochemotherapy with rituximab, cytarabine and fludarabine added to cyclophosphamide, doxorubicin, vincristine and prednisolone and followed by rituximab maintenance in untreated elderly patients with mantle cell lymphoma: a prospective study by the Finnish Lymphoma Group.

There is no consensus on treatment strategies for elderly patients with mantle cell lymphoma (MCL). In this prospective phase II study we investigated whether the poor outcome could be improved, with reasonable toxicity, by prolonging the immunochemotherapy. Ten cycles of alternating cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP)/cytarabine (AraC) with eight doses of rituximab (R) were given as induction. The potential synergism of intermediate-dose AraC and fludarabine was tested in cycles 6-8. Induction was followed by bimonthly rituximab maintenance for 2 years. The median age of the 60 included patients was 74 years, and the Mantle Cell Lymphoma International Prognostic Index (MIPI) was intermediate or high risk in 98% of the patients. The overall response rate was 95% (complete response/complete response unconfirmed 87%). The response of 11 patients improved with cycles 6-8 (R-fludarabine-AraC). Progression-free survival was 70% and overall survival 72% at 4 years, respectively. Treatment related mortality was 2%. Severe infections were rare, with only one grade 4 infection. More dose reductions were needed during fludarabine-containing courses as compared to R-AraC. In 20 patients a transient grade 4 neutropenia without severe infections was recorded during maintenance. In conclusion, elderly patients with MCL can be treated relatively intensively with acceptable toxicity.