PARP-2 ( IC50 = 1 nM ); PARP-1 ( IC50 = 5 nM ); tankyrase-1 ( IC50 = 1.5 μM ); Autophagy; Mitophagy

Olaparib (10 mg/kg, p.o.) greatly inhibits tumor growth in SW620 xenografts when combined with temozolomide.[1] Olaparib (50 mg/kg i.p. daily) responds well to Brca1-/-;p53-/- mammary tumors, but not to HR-deficient Ecad-/-;p53-/- mammary tumors. In mice bearing tumors, olaparib even does not exhibit dose-limiting toxicity. [3] Olaparib has been used to treat BRCA-mutated tumors, including cancers of the breast, prostate, and ovary. Additionally, Olaparib selectively inhibits tumor cells deficient in ATM (Ataxia Telangiectasia Mutated), suggesting that it may be a useful treatment for ATM mutant lymphoid tumors.[4]

The assay assessed Olaparib's capacity to suppress PARP-1 enzyme activity. An alternative method of measuring PARP-2 activity inhibition involves binding down the recombinant PARP-2 protein in a 96-well plate with white walls using an antibody specific to PARP-2. Measurements of PARP-2 activity are made after ³H-NAD⁺ DNA additions. Scintillant is added after washing in order to quantify ³H-incorporated ribosylations. An AlphaScreen assay for tankyrase-1 is created, involving the incubation of HIS-tagged recombinant TANK-1 protein in a 384-well ProxiPlate assay with biotinylated NAD⁺. A proximity signal is produced by adding alpha beads to bind the HIS and biotin tags; the loss of this signal is directly correlated with TANK-1 activity inhibition. At least three replications of each experiment are conducted.

The potentiation factor, or PF50 value, is determined by dividing the IC50 of the alkylating agent methylmethane sulfonate (MMS) used in the control growth by the IC50 of the MMS plus PARP inhibitor. Olaparib is tested for MMS screening at a fixed 200 nM concentration using HeLa B cells. The concentrations of olaparib that are tested on the colorectal cell line SW620 are 1, 3, 10, 100, and 300 nM. Sulforhodamine B (SRB) assay is used to measure cell growth.

Absorption, Distribution and Excretion
Following oral administration, olaparib is rapidly absorbed. After administration of a single 300 mg dose of olaparib, the mean (CV%) Cmax was 5.4 μg/mL (32%) and AUC was 39.2 μg x h/mL (44%). The steady state Cmax and AUC following a dose of 300 mg twice daily was 7.6 μg/mL (35%) and 49.2 μg x h/mL (44%), respectively. Tmax is 1.5 hours. A high-fat and high-calorie meal may delay Tmax, but does not significantly alter the extent of olaparib absorption.
Following a single dose of radiolabeled olaparib, 86% of the dosed radioactivity was recovered within a seven-day collection period, mostly in the form of metabolites. About 44% of the drug was excreted via the urine and 42% of the dose was excreted via the feces. Following an oral dose of radiolabeled olaparib to female patients, the unchanged drug accounted for 15% and 6% of the radioactivity in urine and feces, respectively.
The mean (± standard deviation) apparent volume of distribution of olaparib is 158 ± 136 L following a single 300 mg dose.
Following a single oral dose in patients with cancer, the mean apparent plasma clearance was 4.55 L/h.

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Metabolism / Metabolites
Olaparib is metabolized by cytochrome P450 (CYP) 3A4/5 _in vitro_. Following an oral dose of radiolabeled olaparib to female patients, unchanged olaparib accounted for 70% of the circulating radioactivity in plasma. Olaparib undergoes oxidation reactions as well as subsequent glucuronide or sulfate conjugation. In humans, olaparib can also undergo hydrolysis, hydroxylation, and dehydrogenation. While up to 37 metabolites of olaparib were detected in plasma, urine, and feces, the majority of metabolites represent less than 1% of the total administered dose and they have not been fully characterized. The major circulating metabolites are a ring-opened piperazin-3-ol moiety and two mono-oxygenated metabolites. The pharmacodynamic activity of the metabolites is unknown.

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Biological Half-Life
Following a single oral dose in patients with cancer, the mean terminal half-life was 6.10 hours.

Hepatotoxicity
In large clinical trials of olaparib, abnormalities in routine liver tests were uncommon with serum aminotransferase elevations occurring in 4% of patients and values above 5 times the upper limit of normal (ULN) in 1% or less. In trials of olaparib in patients with various advanced solid tumors there were no reports of hepatitis with jaundice or liver failure. Subsequent to its approval and more widescale use, there have been no published reports of clinically apparent liver injury attributed to olaparib.
Likelihood score: E (unlikely cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of olaparib during breastfeeding. Because olaparib is 82% bound to plasma proteins, the amount in milk is likely to be low. The manufacturer recommends that breastfeeding be discontinued during olaparib therapy and for one month after the last 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.

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Protein Binding
The protein binding of olaparib is approximately 82% _in vitro_. In solutions of purified proteins, the olaparib fraction bound to albumin was approximately 56% and the fraction bound to alpha-1 acid glycoprotein was 29%.

[1]. J Med Chem . 2008 Oct 23;51(20):6581-91.

[2]. Clin Cancer Res . 2008 Jun 15;14(12):3916-25.

[3]. Proc Natl Acad Sci U S A . 2008 Nov 4;105(44):17079-84.

[3]. Blood . 2010 Nov 25;116(22):4578-87.

Olaparib is a member of the class of N-acylpiperazines obtained by formal condensation of the carboxy group of 2-fluoro-5-[(4-oxo-3,4-dihydrophthalazin-1-yl)methyl]benzoic acid with the free amino group of N-(cyclpropylcarbonyl)piperazine; used to treat advanced ovarian cancer. It has a role as an antineoplastic agent, an EC 2.4.2.30 (NAD(+) ADP-ribosyltransferase) inhibitor and an apoptosis inducer. It is a N-acylpiperazine, a member of cyclopropanes, a member of monofluorobenzenes and a member of phthalazines.
Olaparib is a selective and potent inhibitor of poly (ADP-ribose) polymerase (PARP) enzymes, PARP1 and PARP2. PARP inhibitors represent a novel class of anti-cancer therapy and they work by taking advantage of a defect in DNA repair in cancer cells with BRCA mutations and inducing cell death. Olaparib is used to treat a number of BRCA-associated tumours, including ovarian cancer, breast cancer, pancreatic cancer, and prostate cancer. It was first approved by the FDA and EU in December 2014, and by Health Canada in April 2016.
Olaparib is a Poly(ADP-Ribose) Polymerase Inhibitor. The mechanism of action of olaparib is as a Poly(ADP-Ribose) Polymerase Inhibitor.
Olaparib is a small molecule inhibitor of poly ADP-ribose polymerase and is used as an antineoplastic agent in the therapy of refractory and advanced ovarian carcinoma. Olaparib therapy is associated with a low rate of transient elevations in serum aminotransferase during therapy and has not been linked to instances of clinically apparent liver injury.
Olaparib is a small molecule inhibitor of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) with potential chemosensitizing, radiosensitizing, and antineoplastic activities. Olaparib selectively binds to and inhibits PARP, inhibiting PARP-mediated repair of single strand DNA breaks; PARP inhibition may enhance the cytotoxicity of DNA-damaging agents and may reverse tumor cell chemoresistance and radioresistance. PARP catalyzes post-translational ADP-ribosylation of nuclear proteins and can be activated by single-stranded DNA breaks.

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Drug Indication
**Ovarian cancer** Olaparib is indicated for the maintenance treatment of adults with deleterious or suspected deleterious germline or somatic BRCA-mutated advanced epithelial ovarian, fallopian tube or primary peritoneal cancer who are in complete or partial response to first-line platinum-based chemotherapy. Olaparib is indicated in combination with [bevacizumab] for the maintenance treatment of adults with advanced epithelial ovarian, fallopian tube or primary peritoneal cancer who are in complete or partial response to first-line platinum-based chemotherapy and whose cancer is associated with homologous recombination deficiency (HRD)-positive status defined by either: a deleterious or suspected deleterious BRCA mutation, and/or genomic instability. Olaparib is indicated for the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube or primary peritoneal cancer, who are in complete or partial response to platinum-based chemotherapy. **Breast cancer** Olaparib is indicated for the adjuvant treatment of adult patients with deleterious or suspected deleterious g_BRCA_m human epidermal growth factor receptor 2 (HER2)-negative high risk early breast cancer who have been treated with neoadjuvant or adjuvant chemotherapy. Olaparib is indicated for the treatment of adult patients with deleterious or suspected deleterious g_BRCA_m, HER2-negative metastatic breast cancer, who have been treated with chemotherapy in the neoadjuvant, adjuvant, or metastatic setting. Patients with hormone receptor (HR) positive breast cancer should have been treated with a prior endocrine therapy or be considered inappropriate for endocrine therapy. **Pancreatic cancer** Olaparib is indicated for the maintenance treatment of adult patients with deleterious or suspected deleterious gBRCAm metastatic pancreatic adenocarcinoma whose disease has not progressed on at least 16 weeks of a first-line platinum-based chemotherapy regimen. **Prostate cancer** Olaparib is indicated for the treatment of adult patients with deleterious or suspected deleterious germline or somatic homologous recombination repair (HRR) gene-mutated metastatic castration-resistant prostate cancer (mCRPC) who have progressed following prior treatment with a hormone agent, such as [enzalutamide] or [abiraterone]. It is also indicated in combination with [abiraterone] and [prednisone] or [prednisolone] for the treatment of adult patients with deleterious or suspected deleterious BRCA-mutated (BRCAm) metastatic castration-resistant prostate cancer (mCRPC).
Ovarian cancer Lynparza is indicated as monotherapy for the: maintenance treatment of adult patients with advanced (FIGO stages III and IV) BRCA1/2-mutated (germline and/or somatic) high-grade epithelial ovarian, fallopian tube or primary peritoneal cancer who are in response (complete or partial) following completion of first-line platinum-based chemotherapy. maintenance treatment of adult patients with platinum sensitive relapsed high grade epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in response (complete or partial) to platinum based chemotherapy. Lynparza in combination with bevacizumab is indicated for the: maintenance treatment of adult patients with advanced (FIGO stages III and IV) high-grade epithelial ovarian, fallopian tube or primary peritoneal cancer who are in response (complete or partial) following completion of first-line platinum-based chemotherapy in combination with bevacizumab and whose cancer is associated with homologous recombination deficiency (HRD) positive status defined by either a BRCA1/2 mutation and/or genomic instability (see section 5. 1). Breast cancer Lynparza is indicated as: monotherapy or in combination with endocrine therapy for the adjuvant treatment of adult patients with germline BRCA1/2-mutations who have HER2-negative, high risk early breast cancer previously treated with neoadjuvant or adjuvant chemotherapy (see sections 4. 2 and 5. 1). monotherapy for the treatment of adult patients with germline BRCA1/2-mutations, who have HER2 negative locally advanced or metastatic breast cancer . Patients should have previously been treated with an anthracycline and a taxane in the (neo)adjuvant or metastatic setting unless patients were not suitable for these treatments (see section 5. 1). Patients with hormone receptor (HR)-positive breast cancer should also have progressed on or after prior endocrine therapy, or be considered unsuitable for endocrine therapy. Adenocarcinoma of the pancreasLynparza is indicated as: monotherapy for the maintenance treatment of adult patients with germline BRCA1/2-mutations who have metastatic adenocarcinoma of the pancreas and have not progressed after a minimum of 16 weeks of platinum treatment within a first-line chemotherapy regimen. Prostate cancer Lynparza is indicated as: monotherapy for the treatment of adult patients with metastatic castration-resistant prostate cancer (mCRPC) and BRCA1/2-mutations (germline and/or somatic) who have progressed following prior therapy that included a new hormonal agent. in combination with abiraterone and prednisone or prednisolone for the treatment of adult patients with mCRPC in whom chemotherapy is not clinically indicated (see section 5. 1).
Treatment of all conditions included in the category of malignant neoplasms (except central nervous system tumours, haematopoietic and lymphoid tissue neoplasms)

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Mechanism of Action
Poly(ADP-ribose) polymerases (PARPs) are multifunctional enzymes comprising 17 members. They are involved in essential cellular functions, such as DNA transcription and DNA repair. PARPs recognize and repair cellular DNA damage, such as single-strand breaks (SSBs) and double-strand breaks (DSBs). Different DNA repair pathways exist to repair these DNA damages, including the base excision repair (BER) pathway for SSBs and BRCA-dependent homologous recombination for DSBs. Olaparib is a PARP inhibitor: while it acts on PARP1, PARP2, and PARP3, olaparib is a more selective competitive inhibitor of NAD⁺ at the catalytic site of PARP1 and PARP2. Inhibition of the BER pathway by olaparib leads to the accumulation of unrepaired SSBs, which leads to the formation of DSBs, which is the most toxic form of DNA damage. While BRCA-dependent homologous recombination can repair DSBs in normal cells, this repair pathway is defective in cells with BRCA1/2 mutations, such as certain tumour cells. Inhibition of PARP in cancer cells with BRCA mutations leads to genomic instability and apoptotic cell death. This end result is also referred to as synthetic lethality, a phenomenon where the combination of two defects - inhibition of PARP activity and loss of DSB repair by HR - that are otherwise benign when alone, lead to detrimental results. _In vitro_ studies have shown that olaparib-induced cytotoxicity may involve inhibition of PARP enzymatic activity and increased formation of PARP-DNA complexes, resulting in DNA damage and cancer cell death.

C24H23FN4O3

434.46

434.175

C, 66.35; H, 5.34; F, 4.37; N, 12.90; O, 11.05

763113-22-0

23725625

White solid powder

1.4±0.1 g/cm3

1.702

1.9

1

5

4

32

790

0

FC1C([H])=C([H])C(C([H])([H])C2C3=C([H])C([H])=C([H])C([H])=C3C(N([H])N=2)=O)=C([H])C=1C(N1C([H])([H])C([H])([H])N(C([H])([H])C1([H])[H])C(C1([H])C([H])([H])C1([H])[H])=O)=O

FDLYAMZZIXQODN-UHFFFAOYSA-N

InChI=1S/C24H23FN4O3/c25-20-8-5-15(14-21-17-3-1-2-4-18(17)22(30)27-26-21)13-19(20)24(32)29-11-9-28(10-12-29)23(31)16-6-7-16/h1-5,8,13,16H,6-7,9-12,14H2,(H,27,30)

4-[[3-[4-(cyclopropanecarbonyl)piperazine-1-carbonyl]-4-fluorophenyl]methyl]-2H-phthalazin-1-one

AZD2281; Ku-0059436; AZD2281; AZD-2281; AZD 2281; KU59436; KU-59436; KU 59436; KU0059436; KU-0059436; KU 0059436; Olaparib; trade name Lynparza

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: 10 mg/mL (23.02 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 100.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 5 mg/mL (11.51 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 3: ≥ 5 mg/mL (11.51 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 4: ≥ 2.5 mg/mL (5.75 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 5: ≥ 2.5 mg/mL (5.75 mM) (saturation unknown) in 10% DMF 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 6: ≥ 2.5 mg/mL (5.75 mM) (saturation unknown) in 10% DMF 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 7: ≥ 2.5 mg/mL (5.75 mM) (saturation unknown) in 10% DMF 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.

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Solubility in Formulation 8: ≥ 2.08 mg/mL (4.79 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 9: ≥ 0.5 mg/mL (1.15 mM) (saturation unknown) in 1% DMSO 99% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 10: 20 mg/mL (46.03 mM) in 0.5% CMC-Na/saline water (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)