Asciminib in Newly Diagnosed Chronic Myeloid Leukemia.

BACKGROUND: Patients with newly diagnosed chronic myeloid leukemia (CML) need long-term therapy with high efficacy and safety. Asciminib, a BCR::ABL1 inhibitor specifically targeting the ABL myristoyl pocket, may offer better efficacy and safety and fewer side effects than currently available frontline ATP-competitive tyrosine kinase inhibitors (TKIs). METHODS: In a phase 3 trial, patients with newly diagnosed CML were randomly assigned in a 1:1 ratio to receive either asciminib (80 mg once daily) or an investigator-selected TKI, with randomization stratified by European Treatment and Outcome Study long-term survival score category (low, intermediate, or high risk) and by TKI selected by investigators before randomization (including imatinib and second-generation TKIs). The primary end points were major molecular response (defined as BCR::ABL1 transcript levels ≤0.1% on the International Scale [IS]) at week 48, for comparisons between asciminib and investigator-selected TKIs and between asciminib and investigator-selected TKIs in the prerandomization-selected imatinib stratum. RESULTS: A total of 201 patients were assigned to receive asciminib and 204 to receive investigator-selected TKIs. The median follow-up was 16.3 months in the asciminib group and 15.7 months in the investigator-selected TKI group. A major molecular response at week 48 occurred in 67.7% of patients in the asciminib group, as compared with 49.0% in the investigator-selected TKI group (difference, 18.9 percentage points; 95% confidence interval [CI], 9.6 to 28.2; adjusted two-sided P<0.001]), and in 69.3% of patients in the asciminib group as compared with 40.2% in the imatinib group within the imatinib stratum (difference, 29.6 percentage points; 95% CI, 16.9 to 42.2; adjusted two-sided P<0.001). The percentage of patients with a major molecular response at week 48 was 66.0% with asciminib and 57.8% with TKIs in the second-generation TKI stratum (difference, 8.2 percentage points; 95% CI, -5.1 to 21.5). Adverse events of grade 3 or higher and events leading to discontinuation of the trial regimen were less frequent with asciminib (38.0% and 4.5%, respectively) than with imatinib (44.4% and 11.1%) and second-generation TKIs (54.9% and 9.8%). CONCLUSIONS: In this trial comparing asciminib with investigator-selected TKIs and imatinib, asciminib showed superior efficacy and a favorable safety profile in patients with newly diagnosed chronic-phase CML. Direct comparison between asciminib and second-generation TKIs was not a primary objective. (Funded by Novartis; ASC4FIRST ClinicalTrials.gov number, NCT04971226).

Asciminib is a novel inhibitor of ABL1 and ABL2 gene fusions in ALL but requires the ABL SH3 domain for efficacy.

High-risk Ph-like ALL includes genomic rearrangement of the ABL1 and ABL2 genes (collectively ABL-rearranged, ABLr), and novel treatments are required. For the first time, we demonstrate asciminib efficacy in ABLr ALL, but only when the ABL SH3 domain is present.

Asciminib Monotherapy as Frontline Treatment of Chronic-Phase Chronic Myeloid Leukemia: Results from the ASCEND Study.

Asciminib is a myristoyl site BCR::ABL1 inhibitor approved for chronic phase chronic myeloid leukaemia (CP-CML) patients failing ≥2 prior lines of therapy. The Australasian Leukaemia & Lymphoma Group (ALLG) conducted the ASCEND study to assess efficacy of asciminib for newly-diagnosed CP-CML. Patients commenced asciminib 40 mg twice daily (BID) and thereafter were managed according to molecular milestones. Patients with treatment failure, defined as BCR::ABL1 >10% (IS) at 3 or 6 months, or >1% at 12 or 18 months, received either imatinib, nilotinib or dasatinib in addition to asciminib. In patients with suboptimal response, defined as levels of 1-10% at 6 months, >0.1-1% at 12 months, or >0.01%-1% at 18 months, the asciminib dose was increased to 80 mg BID. With a median follow-up of 21 months (range 0-36), 82/101 patients continue asciminib. The most frequent reasons for treatment discontinuation were adverse events (6%), loss of response (4%) and withdrawn consent (5%). There were no deaths; one patient developed lymphoid blast crisis at 6 months. The co-primary endpoints were early molecular response (BCR::ABL1 ≤10% at 3 months), achieved in 93% (96% CI 86-97%), and major molecular response by 12 months achieved in 79%; (95% CI 69.7-86.8%), respectively. The cumulative incidence of MR4.5 was 53% by 24 months. One patient had 2 cerebrovascular events; no other arterial occlusive events were reported. Asciminib as frontline therapy in CP-CML produces high rates of molecular response with excellent tolerance and a low rate of discontinuation for toxicity. (ANZ Clinical Trials Registry ACTRN12620000851965).

Asciminib monotherapy in patients with chronic-phase chronic myeloid leukemia with the T315I mutation after ≥1 prior tyrosine kinase inhibitor: 2-year follow-up results.

Asciminib targets the BCR::ABL1 myristoyl pocket, maintaining activity against BCR::ABL1T315I, which is resistant to most approved adenosine triphosphate-competitive tyrosine kinase inhibitors. We report updated phase I results (NCT02081378) assessing safety/tolerability and antileukemic activity of asciminib monotherapy 200 mg twice daily in 48 heavily pretreated patients with T315I-mutated chronic-phase chronic myeloid leukemia (CML-CP; data cutoff: January 6, 2021). With 2 years' median exposure, 56.3% of patients continued receiving asciminib. Overall, 62.2% of evaluable patients achieved BCR::ABL1 ≤1% on the International Scale (IS); 47.6% and 81.3% of ponatinib-pretreated and -naive patients, respectively, achieved BCR::ABL1IS ≤1%. Of 45 evaluable patients, 48.9% achieved a major molecular response (MMR, BCR::ABL1IS ≤0.1%), including 34.6% and 68.4% of ponatinib-pretreated and -naive patients, respectively. MMR was maintained until data cutoff in 19 of 22 patients who achieved it. The most common grade ≥3 adverse events (AEs) included increased lipase level (18.8%) and thrombocytopenia (14.6%). Five (10.4%) patients experienced AEs leading to discontinuation, including 2 who discontinued asciminib and died due to COVID-19; these were the only deaths reported. These results show asciminib's effectiveness, including in almost 50% of ponatinib pretreated patients, and confirm its risk-benefit profile, supporting its use as a treatment option for T315I-mutated CML-CP.