Acalabrutinib

This chemical does not meet GHS hazard criteria for 33.3% (1 of 3) of reports.

Warning

H373 (66.7%): May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

P260, P319, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 3 reports by companies from 3 notifications to the ECHA C&L Inventory.；Reported as not meeting GHS hazard criteria per 1 of 3 reports by companies.；There are 2 notifications provided by 2 of 3 reports by companies with hazard statement code(s).；Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

In open label clinical trials of acalabrutinib in patients with CLL and mantle cell lymphoma, serum aminotransferase elevations occurred in 19% to 23% of patients during therapy and rose to above 5 times ULN in 2% to 3%. These elevations were transient and resolved spontaneously but occasionally led to early drug discontinuation. Among the 610 patients treated with acalabrutinib in pre-registration trials, there were no instances of clinically apparent liver injury attributed to its use, but there was a single instance of acute liver failure and death due to reactivation of hepatitis B. Similar cases of reactivation have been reported with ibrutinib, another small molecule inhibitor of Bruton's tyrosine kinase. Experience with acalabrutinib has been limited and the frequency of clinically apparent liver injury and reactivation of hepatitis B are not known. The majority of cases have occurred in patients taking multiple immunosuppressive agents and not just acalabrutinib alone.；Likelihood score: D (possible rare cause of reactivation of hepatitis B).

Drug Induced Liver Injury Rank (DILIrank 2.0)

Acalabrutinib

Ambiguous-DILI-concern

4

Adverse reactions

DOI:10.1016/j.drudis.2016.02.015

◉ Summary of Use during Lactation；No information is available on the clinical use of acalabrutinib during breastfeeding. Because acalabrutinib is over 97% bound to plasma proteins, and the half-life of the drug and metabolite are less than 7 hours, the amount in milk is likely to be low. However, the protein binding of the active metabolite is not known and the manufacturer recommends that breastfeeding be discontinued during acalabrutinib therapy and for at least 2 weeks after the final dose.；◉ Effects in Breastfed Infants；Relevant published information was not found as of the revision date.；◉ Effects on Lactation and Breastmilk；Relevant published information was not found as of the revision date.

L - Antineoplastic and immunomodulating agents；L01 - Antineoplastic agents；L01E - Protein kinase inhibitors；L01EL - Bruton's tyrosine kinase (btk) inhibitors；L01EL02 - Acalabrutinib

QL - Antineoplastic and immunomodulating agents；QL01 - Antineoplastic agents；QL01E - Protein kinase inhibitors；QL01EL - Bruton's tyrosine kinase (btk) inhibitors；QL01EL02 - Acalabrutinib

Reversible binding of acalabrutinib to human plasma protein is approximately 97.5%. The in vitro mean blood-to-plasma ratio is about 0.7. _In vitro_ experiments at physiologic concentrations show that acalabrutinib can be 93.7% bound to human serum albumin and 41.1% bound to alpha-1-acid glycoprotein.

Acalabrutinib is a Bruton Tyrosine Kinase inhibitor that prevents the proliferation, trafficking, chemotaxis, and adhesion of B cells. It is taken every 12 hours and can cause other effects such as atrial fibrillation, other malignancies, cytopenia, hemorrhage, and infection.

Mantle Cell Lymphoma (MCL) is a rare yet aggressive type of B-cell non-Hodgkin lymphoma (NHL) with poor prognosis. Subsequently, relapse is common in MCL patients and ultimately represents disease progression. Lymphoma occurs when immune system lymphocytes grow and multiply uncontrollably. Such cancerous lymphocytes may travel to many parts of the body, including the lymph nodes, spleen, bone marrow, blood, and other organs where they can multiply and form a mass(es) called a tumor. One of the main kinds of lymphocytes that can develop into cancerous lymphomas are the body's own B-lymphocytes (B-cells). Bruton Tyrosine Kinase (BTK) is a signalling molecule of the B-cell antigen receptor and cytokine receptor pathways. Such BTK signaling causes the activation of pathways necessary for B-cell proliferation, trafficking, chemotaxis, and adhesion. Acalabrutinib is a small molecule inhibitor of BTK. Both acalabrutinib and its active metabolite, ACP-5862, act to form a covalent bond with a cysteine residue (Cys481) in the BTK active site, leading to inhibition of BTK enzymatic activity. As a result, acalabrutinib inhibits BTK-mediated activation of downstream signaling proteins CD86 and CD69, which ultimately inhibits malignant B-cell proliferation and survival Whereas ibrutinib is typically recognized as the first-in-class BTK inhibitor, acalabrutinib is considered a second generation BTK inhibitor primarily because it demonstrates highter selectivity and inhibition of the targeted activity of BTK while having a much greater IC50 or otherwise virtually no inhibition on the kinase activities of ITK, EGFR, ERBB2, ERBB4, JAK3, BLK, FGR, FYN, HCK, LCK, LYN, SRC, and YES1. In effect, acalabrutinib was rationally designed to be more potent and selective than ibrutinib, all the while demonstrating fewer adverse effects - in theory - because of the drug's minimized off target effects.

After administering a single oral dose of 100 mg acalabrutinib, the median terminal elimination half-life of the drug was found to be 0.9 (with a range of 0.6 to 2.8) hours. The half-life of the active metabolite, ACP-5862, is about 6.9 hours.

Acalabrutinib is mainly metabolized by CYP3A enzymes. ACP-5862 is identified to be the major active metabolite in plasma with a geometric mean exposure (AUC) that is about 2-3 times greater than the exposure of acalabrutinib. ACP-5862 is about 50% less potent than acalabrutinib in regards to the inhibition of BTK.

I42748ELQW

ACALABRUTINIB

Established Pharmacologic Class [EPC] - Kinase Inhibitor

Mechanisms of Action [MoA] - Tyrosine Kinase Inhibitors

Acalabrutinib is a Kinase Inhibitor. The mechanism of action of acalabrutinib is as a Tyrosine Kinase Inhibitor.

ACALABRUTINIB

Substances that inhibit or prevent the proliferation of NEOPLASMS.

Protein kinase inhibitors that inhibit TYROSINE PROTEIN KINASES.

The geometric mean absolute bioavailability of acalabrutinib is 25% with a median time to peak plasma concentrations (Tmax) of 0.75 hours.

After administration of a single 100 mg radiolabelled acalabrutinib dose in healthy subjects, 84% of the dose was recovered in the feces and 12% of the dose was recovered in the urine. An irradiated dose of acalabrutinib was 34.7% recovered as the metabolite ACP-5862; 8.6% was recovered as unchanged acalabrutinub; 10.8 was recovered as a mixture of the M7, M8, M9, M10, and M11 metabolites; 5.9% was the M25 metabolite; 2.5% was recovered as the M3 metabolite.

The mean steady-state volume of distribution is approximately 34 L.

Acalabrutinib's mean apparent oral clearance (CL/F) is observed to be 159 L/hr with similar PK between patients and healthy subjects, based on population PK analysis.