Niraparib, sold under the brand name Zejula, is an anti-cancer medication used for the treatment of epithelial ovarian, fallopian tube, or primary peritoneal cancer. It is taken

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

. It is a

PARP inhibitor PARP inhibitors are a group of pharmacological inhibitors of the enzyme poly ADP ribose polymerase (PARP). They are developed for multiple indications, including the treatment of heritable cancers. Several forms of cancer are more dependent o ...

. The most common side effects include

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 ...

(feeling sick),

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 a ...

(low blood platelet counts), tiredness and weakness,

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, t ...

(low red blood cell counts),

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteri ...

, abdominal (belly) pain, neutropenia (low levels of neutrophils, a type of white blood cell),

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

(difficulty sleeping), headache, lack of appetite,

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

dyspnea Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

(difficulty breathing), hypertension (high blood pressure), back pain, dizziness, cough, joint pain, hot flushes and decrease in white blood cells. Niraparib was approved for medical use in the United States and in the European Union in 2017.

Medical uses

Niraparib is

indicated In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosis ...

for the maintenance treatment of adults with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to

platinum-based chemotherapy Platinum-based antineoplastic drugs (informally called platins) are chemotherapeutic agents used to treat cancer. They are coordination complexes of platinum. These drugs are used to treat almost half of people receiving chemotherapy for cancer. I ...

. In October 2019, the indication for niraparib was expanded to include people with advanced ovarian, fallopian tube, or primary peritoneal cancer treated with three or more prior chemotherapy regimens and whose cancer is associated with homologous recombination deficiency (HRD)-positive status. HRD is defined by either a deleterious or suspected deleterious BRCA mutation, or genomic instability in patients with disease progression greater than six months after response to the last platinum-based chemotherapy. In April 2020, the indication for niraparib was expanded to include the maintenance treatment of adults with advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to first-line platinum-based chemotherapy. In the European Union, niraparib is indicated: as monotherapy for the maintenance treatment of adults with advanced epithelial (FIGO Stages III and IV) high-grade ovarian, fallopian tube or primary peritoneal cancer who are in response (complete or partial) following completion of first-line platinum-based chemotherapy; and as monotherapy for the maintenance treatment of adults with platinum sensitive relapsed high grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in response (complete or partial) to platinum based chemotherapy.

Contraindications

No contraindications are listed in the prescribing information.

Side effects

The most common side effects in studies were low blood cell counts, namely

(in 61% of patients, severe in 29%),

(in 50%, severe in 25%) and neutropenia (in 30%, severe in 20%). Other, mostly mild to moderate side effects included

, fatigue, and

. In a study running over 250 days ( median), 15% of patients had to permanently discontinue niraparib due to adverse effects.

Interactions

No clinical interaction studies have been performed. The potential for interactions with other drugs is low as niraparib and its main metabolite M1 do not significantly interact with any of the important

cytochrome P450 Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various co ...

liver enzymes ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology ...

''. Niraparib, but not M1, is transported by P-glycoprotein and

BCRP ATP-binding cassette super-family G member 2 is a protein that in humans is encoded by the ''ABCG2'' gene. ABCG2 has also been designated as CDw338 (cluster of differentiation w338). ABCG2 is a translocation protein used to actively pump drugs a ...

, but does not significantly inhibit them. Neither niraparib nor M1 significantly interact with any of the other important transporter proteins.

Pharmacology

Mechanism of action

Niraparib is an inhibitor of the enzymes

PARP1 Poly DP-ribosepolymerase 1 (PARP-1) also known as NAD+ ADP-ribosyltransferase 1 or poly DP-ribosesynthase 1 is an enzyme that in humans is encoded by the ''PARP1'' gene. It is the most abundant of the PARP family of enzymes, accounting for 90% o ...

and PARP2.

Pharmacokinetics

73% of ingested niraparib is absorbed in the gut, and it reaches highest

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 intr ...

concentrations after about three hours, independently of food intake. In the circulation, 83% of the substance are 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. It is inactivated by

carboxylesterase The enzyme carboxylesterase (or carboxylic-ester hydrolase, EC 3.1.1.1; systematic name carboxylic-ester hydrolase) catalyzes reactions of the following form: :a carboxylic ester + H2O \rightleftharpoons an alcohol + a carboxylate Most enzymes fr ...

s to the main metabolite M1, the carboxylic acid derivative, which is subsequently

glucuronidated Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosid ...

. The mean

biological 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 36 hours. 47.5% of the substance are found in the urine and 38.8% in the feces. Unmetabolised niraparib accounts for 11% in the urine and 19% in the feces.

Chemistry

The drug is used in form of the salt niraparib

tosylate In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos) is a univalent functional group with the chemical formula –. It consists of a tolyl group, –, joined to a sulfonyl group, ––, with the open valence on s ...

monohydrate, which is white to off-white, non-

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substan ...

crystals.

Studies

A 2012 study in a cell line found that PARP inhibitors exhibit cytotoxic effects not based solely on their enzymatic inhibition of PARP, but by their trapping of PARP on damaged DNA, and the strength of this trapping activity was ordered niraparib >>

olaparib Olaparib, sold under the brand name Lynparza, is a medication for the maintenance treatment of BRCA-mutated advanced ovarian cancer in adults. It is a PARP inhibitor, inhibiting poly ADP ribose polymerase (PARP), an enzyme involved in DNA repair ...

>> veliparib.

History

Niraparib was granted

fast track designation Fast track is a designation by the United States Food and Drug Administration (FDA) of an investigational drug for expedited review to facilitate development of drugs that treat a serious or life-threatening condition and fill an unmet medical ...

by the US

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), and Tesaro submitted a new drug application in 2016. It was approved on 27 March 2017 in the US, and approved in European Union on 16 November 2017. In a study with 553 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 ...

(PFS) for patients with a deleterious or suspected deleterious

BRCA mutation A ''BRCA'' mutation is a mutation in either of the ''BRCA1'' and ''BRCA2'' genes, which are tumour suppressor genes. Hundreds of different types of mutations in these genes have been identified, some of which have been determined to be harmful, ...

in the germline was 21.0 months under niraparib therapy, as compared to 5.5 months under

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), sham surgery, and other procedures. In general, placebos can af ...

. Patients without such a mutation had a PFS of 9.3 months under niraparib versus 3.9 months under placebo. The US

(FDA) granted the application for niraparib

fast track The fast track is an informal English term meaning "the quickest and most direct route to achievement of a goal, as in competing for professional advancement". By definition, it implies that a less direct, slower route also exists. Fast track or F ...

priority review Priority review is a program of the United States Food and Drug Administration (FDA) to expedite the review process for drugs that are expected to have a particularly great impact on the treatment of a disease. The priority review voucher program ...

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 ...

, and orphan drug designations.

References

External links

* * * * {{Portal bar , Medicine Breakthrough therapy Indazolecarboxamides GSK plc brands Orphan drugs PARP inhibitors Piperidines