Abemaciclib, sold under the brand name Verzenio among others, is a

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...

for the treatment of advanced or metastatic

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...

s. It was developed by

Eli Lilly Eli Lilly (July 8, 1838 – June 6, 1898) was an American soldier, pharmacist, chemist, and businessman who founded the Eli Lilly and Company pharmaceutical corporation. Lilly enlisted in the Union Army during the American Civil War and r ...

and it acts as a

CDK inhibitor A CDK (cyclin-dependent kinase) inhibitor is any chemical that inhibits the function of CDKs. They are used to treat cancers by preventing overproliferation of cancer cells. The US FDA approved the first drug of this type, palbociclib (Ibrance), ...

selective for

CDK4 Cyclin-dependent kinase 4 also known as cell division protein kinase 4 is an enzyme that in humans is encoded by the ''CDK4'' gene. CDK4 is a member of the cyclin-dependent kinase family. Function The protein encoded by this gene is a member o ...

and

CDK6 Cell division protein kinase 6 (CDK6) is an enzyme encoded by the ''CDK6'' gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of th ...

. It was designated as a

breakthrough therapy Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development that was created by Congress under Section 902 of the 9 July 2012 Food and Drug Administration Safety and Innovation Act. The FDA's "br ...

for breast cancer by the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) in October 2015. On 28 September 2017, it was approved for use in the United States by the FDA for the treatment of certain breast cancers.

Medical uses

Since September 2017 Abemaciclib is approved in the US for "adult patients who have hormone receptor (HR)-positive,

human epidermal growth factor receptor 2 Receptor tyrosine-protein kinase erbB-2 is a protein that in humans is encoded by the ''ERBB2'' gene. ERBB is abbreviated from erythroblastic oncogene B, a gene originally isolated from the avian genome. The human protein is also frequently refer ...

(HER2)-negative advanced or metastatic breast cancer that has progressed after taking therapy that alters a patient's hormones". In studies that compared

fulvestrant Fulvestrant, sold under the brand name Faslodex among others, is a medication used to treat hormone receptor (HR)-positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced br ...

plus abemaciclib to fulvestrant plus

placebo A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures. In general ...

in breast cancer patients,

progression-free survival Progression-free survival (PFS) is "the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease but it does not get worse". In oncology, PFS usually refers to situations in which a tumor is p ...

under abemaciclib therapy was 16.4 months on average, as compared to 9.3 months under the placebo arm.

Side effects

Side effects that occurred in 20% or more of patients in studies were diarrhea,

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

and vomiting,

leukopenia Leukopenia () is a decrease in the number of leukocytes (WBC). Found in the blood, they are the white blood cells, and are the body's primary defense against an infection. Thus the condition of leukopenia places individuals at increased risk of inf ...

(low white blood cell count) including

neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...

(low red blood cell count),

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients an ...

(low platelet count), stomach pain, infections,

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

, decreased appetite, and headache.

Interactions

As abemaciclib is mainly metabolized by the liver enzyme

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...

, inhibitors of this enzyme (such as

ketoconazole Ketoconazole, sold under the brand name Nizoral among others, is an antiandrogen and antifungal medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous candid ...

) are expected to increase its

blood plasma Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intra ...

concentrations. Conversely, CYP3A4 inducers lower plasma concentrations of abemaciclib, as has been shown in a study with

rifampicin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), mycobacterium avium complex, ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. ...

Pharmacology

Mechanism of action

Like the related drugs

palbociclib Palbociclib, sold under the brand name Ibrance among others, is a medication developed by Pfizer for the treatment of HR-positive and HER2-negative breast cancer. It is a selective inhibitor of the cyclin-dependent kinases CDK4 and CDK6. Pal ...

and

ribociclib Ribociclib, sold under the brand name Kisqali and Kryxana marketed by Novartis, is an inhibitor of cyclin D1/CDK4 and CDK6, and is used for the treatment of certain kinds of breast cancer. on Kisqali. Accessed 2017-09-08. Ribociclib is a kinase in ...

, abemaciclib inhibits the enzymes

cyclin-dependent kinase 4 Cyclin-dependent kinase 4 also known as cell division protein kinase 4 is an enzyme that in humans is encoded by the ''CDK4'' gene. CDK4 is a member of the cyclin-dependent kinase family. Function The protein encoded by this gene is a member o ...

(CDK4) and

cyclin-dependent kinase 6 Cell division protein kinase 6 (CDK6) is an enzyme encoded by the ''CDK6'' gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of t ...

(CDK6). These enzymes are responsible for

phosphorylating In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, whi ...

and thus deactivating the

retinoblastoma protein The retinoblastoma protein (protein name abbreviated pRb; gene name abbreviated ''Rb'', ''RB'' or ''RB1'') is a proto-oncogenic tumor suppressor protein that is dysfunctional in several major cancers. One function of pRb is to prevent excessive ...

, which plays a role in

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subs ...

progression from the G1 ( first gap) to the S (

synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors ** Organic synthesis, the chemical synthesis of organ ...

) phase. Blocking this pathway prevents cells from progressing to the S phase, thereby inducing

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

(cell death). In vitro analysis using cancer cell lines, it is reported that abemaciclib induces non‐apoptotic cell death characterized by formation of cytoplasmic vacuoles derived from lysosomes. This result suggests that there may be a mechanism of action other than inhibition of a cyclin-dependent kinase.

Pharmacokinetics

After oral intake, absolute

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

is 45%. Highest blood plasma concentrations are reached after 8 hours on average (range: 4.1–24.0 hours). When in the circulation, 96.3% of abemaciclib is bound to

plasma protein Blood-proteins, also termed plasma proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, hormones, vitamins and minerals in activity and functioning of the immune system. Other blood pr ...

s. The substance is mainly metabolized by the liver enzyme CYP3A4 to ''N''-desethylabemaciclib (M2), and to a lesser extent to hydroxy derivatives (M18, M20) and another

oxidative Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

metabolite (M1). These metabolites have high plasma protein binding rates similar to the parent substance. Abemaciclib is excreted mainly via the feces (81%) and to a small extent via the urine (3%). Its

elimination half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...

is 18.3 hours on average.

Clinical trials

Successful Phase I and Phase II trials against breast cancer were announced in May and December 2014 respectively. As of early 2016, abemaciclib was involved in 3 Phase III clinical trials: * The JUNIPER StudyA Study of Abemaciclib (LY2835219) in Participants With Previously Treated KRAS Mutated Lung Cancer (JUNIPER)
/ref> is comparing abemaciclib against

erlotinib Erlotinib, sold under the brand name Tarceva among others, is a medication used to treat non-small cell lung cancer (NSCLC) and pancreatic cancer. Specifically it is used for NSCLC with mutations in the epidermal growth factor receptor (EGFR) � ...

in patients with stage IV

non-small-cell lung carcinoma Non-small-cell lung cancer (NSCLC) is any type of epithelial lung cancer other than small-cell lung carcinoma (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to sm ...

Due to collect data until September 2017. * The MONARCH 2 study is investigating the effectiveness of abemaciclib in combination with

for women with breast cancer. It is due to end in Feb 2017. In March 2017, Eli Lilly announced that it had met its

primary endpoint Clinical endpoints or clinical outcomes are outcome measures referring to occurrence of disease, symptom, sign or laboratory abnormality constituting a target outcome in clinical research trials. The term may also refer to any disease or sign tha ...

of superior

(PFS) over

plus fulvestrant in patients with

estrogen receptor Estrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen ( 17β-estradiol). Two classes of ER exist: nuclear estrogen receptors (ERα and ERβ), which are members of the ...

positive and

HER2 Receptor tyrosine-protein kinase erbB-2 is a protein that in humans is encoded by the ''ERBB2'' gene. ERBB is abbreviated from erythroblastic oncogene B, a gene originally isolated from the avian genome. The human protein is also frequently refer ...

negative advanced or metastatic breast cancer.Lilly Announces Phase 3 MONARCH 2 Breast Cancer Study of Abemaciclib Met Primary Endpoint of Progression-Free Survival, Eli Lilly, 20 March 2017
/ref> This result led to the September 2017 FDA approval. * The MONARCH 3 studyA Study of Nonsteroidal Aromatase Inhibitors Plus Abemaciclib (LY2835219) in Postmenopausal Women With Breast Cancer (MONARCH 3)
/ref> is investigating the effectiveness of abemaciclib, plus either

anastrozole Anastrozole, sold under the brand name Arimidex among others, is a medication used in addition to other treatments for breast cancer. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast ca ...

letrozole Letrozole, sold under the brand name Femara among others, is an aromatase inhibitor medication that is used in the treatment of breast cancer. It was patented in 1986 and approved for medical use in 1996. In 2020, it was the 257th most common ...

, as a first-line treatment for women with breast cancer. The trial is expected to end in June 2017.

Chemistry

Abemaciclib may be synthesized in a four step manner using a

Suzuki coupling The Suzuki reaction is an organic reaction, classified as a cross-coupling reaction, where the coupling partners are a boronic acid and an organohalide and the catalyst is a palladium(0) complex. It was first published in 1979 by Akira Suzuki, a ...

, followed by a

Buchwald–Hartwig amination In organic chemistry, the Buchwald–Hartwig amination is a chemical reaction for the synthesis of carbon–nitrogen bonds via the cross-coupling reaction, palladium-catalyzed coupling reactions of amines with aryl halides. Although Pd-catalyzed ...

with the final step being a

reductive amination Reductive amination (also known as reductive alkylation) is a form of amination that involves the conversion of a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is considered ...

using the

Leuckart reaction The Leuckart reaction is the chemical reaction that converts aldehydes or ketones to amines by reductive amination in the presence of heat. The reaction, named after Rudolf Leuckart, uses either ammonium formate or formamide as the nitrogen donor ...

References

External links

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