Asciminib

Breast Feeding; Lactation; Milk, Human; Antineoplastic Agents; Enzyme Inhibitors; Protein Kinase Inhibitors; Tyrosine Kinase Inhibitors

EMA approved medicines: Human medicine (Orphan designations)

In the prelicensure clinical trials of asciminib in patients with refractory and extensively treated CML, ALT elevations arose in 13% of patients but were usually self-limited and mild. ALT elevations above 5 times the upper limit of normal (ULN) were uncommon, being found in 3% of treated patients. The ALT elevations were typically transient and rarely required dose interruption or modification. In the open label and controlled trials supporting the approval of asciminib, there were no instances of clinically apparent liver injury, hepatic failure or deaths from liver injury. Furthermore, patients with aminotransferase elevations during therapy with first and second line BCR-ABL1 inhibitors did not have an increased rate of such elevations during asciminib therapy. Since its approval in the United States and Europe, there have been no reported cases of clinically apparent liver injury associated with asciminib therapy.

L - Antineoplastic and immunomodulating agents

QL - Antineoplastic and immunomodulating agents

Asciminib exerts its therapeutic activity by inhibiting an oncogenic protein responsible for the proliferation of CML. It may be administered orally once or twice a day depending on the condition being treated. By increasing the total daily dose 5-fold as compared to standard therapy (80mg daily vs. 400mg daily), it can be used to treat Ph+ CML with the T315I mutation, a typically treatment-resistant variant of the disease. As with many other chemotherapeutic agents, asciminib treatment can result in various forms of myelosuppression, including thrombocytopenia and neutropenia. Patients should receive frequent laboratory monitoring throughout therapy and dose adjustments may be required based on the severity of observed effects. Patients may also experience pancreatic and/or cardiovascular toxicity, both of which require frequent monitoring and may require dose adjustments as per prescribing information.

In most patients with chronic myeloid leukemia (CML), progression of the disease is driven primarily by a translocation of the Philadelphia chromosome that creates an oncogenic fusion gene, _BCR-ABL1_, between the _BCR_ and _ABL1_ genes. This fusion gene produces a resultant fusion protein, BCR-ABL1, which exhibits elevated tyrosine kinase and transforming activities that contribute to CML proliferation. Asciminib is an allosteric inhibitor of the BCR-ABL1 tyrosine kinase. It binds to the myristoyl pocket of the ABL1 portion of the fusion protein and locks it into an inactive conformation, preventing its oncogenic activity.

Asciminib is negligibly metabolized, with unchanged parent drug comprising the main drug component in plasma (~93%) and following excretion (~57% in feces). The main circulating metabolites are M30.5, M44, and M29.5, accounting for approximately 5%, 2%, and 0.4% of the total administered dose, respectively. The oxidative metabolism of asciminib is mediated by CYP3A4, and the glucuronidation of asciminib is mediated by UGT2B7 and UGT2B17.

The median Tmax of asciminib following oral administration is 2.5 hours. At a dose of 80mg once daily, the steady-state Cmax and AUCtau were 1781 ng/mL and 15112 ng.h/mL, respectively. At a dose of 40mg twice daily, the steady-state Cmax and AUCtau were 793 ng/mL and 5262 ng.h/mL, respectively. At a dose of 200mg twice daily (for treatment of T315I mutants), the steady-state Cmax and AUCtau were 5642 ng/mL and 37547 ng.h/mL, respectively. As compared to the fasted state, the co-administration of asciminib with a high-fat meal decreased the AUC and Cmax by 62% and 68%, respectively, and its co-administration with a low-fat meal decreased the AUC and Cmax by 30% and 35%, respectively.

Asciminib is eliminated via biliary secretion facilitated by breast cancer-resistant protein (BCRP) transporters. Following oral administration, approximately 80% and 11% of an asciminib dose was recovered in the feces and urine, respectively. Unchanged parent drug accounted for 57% of drug material recovered in the feces and 2.5% in the urine.

At steady-state, the apparent volume of distribution of asciminib is 151 L.

The total apparent clearance of asciminib is 6.7 L/h at a total daily dose of 80mg and 4.1 L/h at a dose of 200mg twice daily.