Oladx Olaparib

I. Drug Name

Generic Name: Olaparib Tablets

English Name: Olaparib

Brand Names: Lynparza, Lipzhuo, Oladx

Dosage Form: Oral Film-Coated Tablets

Specification: 150 mg per tablet; 56 tablets per box

Manufacturer: Laos Da Xiong Pharmaceutical Co., Ltd.

Drug Approval Number: 03 L1085/24

II. Pharmacological Actions

Pharmacological Classification: Poly (ADP-ribose) polymerase (PARP) inhibitor

Mechanism of Action:

PARP enzymes (specifically PARP-1 and PARP-2) play a critical role in the repair of single-strand DNA damage within cells.

Olaparib inhibits the activity of PARP enzymes, thereby preventing the repair of single-strand DNA damage, which subsequently progresses into double-strand DNA breaks.

In tumor cells harboring *BRCA1/2* gene mutations or other homologous recombination repair (HRR) defects, the intrinsic double-strand DNA repair mechanisms are already compromised. Under these conditions, the DNA damage induced by Olaparib cannot be repaired, ultimately leading to tumor cell apoptosis.

This mechanism of action is referred to as "synthetic lethality"—the simultaneous inhibition of PARP in the presence of HRR defects (such as *BRCA* mutations) selectively kills cancer cells while having minimal impact on normal cells.

III. Indications

Olaparib is indicated for the treatment of the following adult patients (specific indications may vary depending on regional regulatory approvals):

1. Ovarian Cancer:

As maintenance therapy for adult patients with advanced epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer who harbor germline or somatic *BRCA* mutations and have achieved a complete or partial response following first-line platinum-based chemotherapy.

As maintenance therapy for adult patients with recurrent epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer who are platinum-sensitive and have achieved a complete or partial response following platinum-based chemotherapy.

For the treatment of adult patients with advanced epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer who harbor germline *BRCA* mutations (and have previously received at least two lines of chemotherapy). 2.  **Breast Cancer:**

Indicated for adult patients with germline *BRCA*-mutated, HER2-negative metastatic breast cancer (who have previously received chemotherapy in the adjuvant, neoadjuvant, or metastatic setting).

3.  **Pancreatic Cancer:**

Indicated as maintenance therapy for adult patients with germline *BRCA*-mutated metastatic pancreatic cancer (who have not progressed after at least 16 weeks of first-line platinum-based chemotherapy).

4.  **Prostate Cancer:**

Indicated for adult patients with metastatic castration-resistant prostate cancer (mCRPC) who harbor germline or somatic homologous recombination repair (HRR) gene mutations (who have progressed following prior treatment with a novel hormonal agent).

**IV. Dosage and Administration**

**Recommended Dosage:** 300 mg (two 150 mg tablets) taken orally twice daily (approximately every 12 hours).

**Administration Instructions:**

Swallow tablets whole. 

May be taken with or without food. 

If a dose is missed, do not take an extra dose; wait until the next scheduled time to take the regular dose. 

If vomiting occurs after taking a dose, do not take an extra dose; wait until the next scheduled time to take the regular dose.

**V. Contraindications**

Patients with a history of severe hypersensitivity to olaparib or to any of the excipients.

**VI. Warnings and Precautions**

1.  **Myelodysplastic Syndrome/Acute Myeloid Leukemia (MDS/AML):**

MDS/AML has been reported in patients treated with olaparib in clinical trials; some cases were fatal. 

Monitor patients for complete blood counts prior to starting treatment. Monitor monthly during treatment, and periodically for patients receiving long-term treatment. 

If MDS/AML is confirmed, discontinue olaparib permanently.

2.  **Pneumonitis:**

Severe and fatal pneumonitis may occur. 

Interrupt treatment immediately in patients who present with new or worsening respiratory symptoms (e.g., dyspnea, cough, fever) and evaluate for pneumonitis. If pneumonitis is confirmed, discontinue olaparib permanently. 3. Embryo-Fetal Toxicity:

Based on its mechanism of action, Olaparib may cause fetal harm when administered to a pregnant woman. 

Verify the pregnancy status of females of reproductive potential prior to initiating treatment.

Females of reproductive potential should use effective contraception during treatment and for at least 6 months after the last dose.

Male patients (due to the potential for genotoxicity in sperm) should use effective condoms during treatment and for at least 3 months after the last dose when engaging in sexual intercourse with a pregnant woman or a female of reproductive potential; they are also advised not to donate sperm.

VII. Adverse Reactions

Very Common (>10%) Serious and/or Major Adverse Reactions:

Gastrointestinal: Nausea, vomiting, diarrhea, abdominal pain, dyspepsia. 

General: Fatigue/asthenia, headache. 

Hematologic and Lymphatic Systems: Anemia, lymphopenia, neutropenia, thrombocytopenia. 

Laboratory Abnormalities: Increased creatinine, increased mean corpuscular volume (MCV). 

Respiratory: Cough.

Common but Serious Adverse Reactions:

MDS/AML, pneumonia.

VIII. Drug Interactions

Strong CYP3A Inhibitors (e.g., clarithromycin, itraconazole, ritonavir):

Co-administration significantly increases Olaparib plasma concentrations, thereby increasing the risk of adverse reactions.

Avoid co-administration. If co-administration is unavoidable, reduce the Olaparib dose to 100 mg twice daily.

Strong CYP3A Inducers (e.g., rifampin, carbamazepine, St. John's wort):

Co-administration significantly decreases Olaparib plasma concentrations, potentially reducing efficacy. 

Avoid co-administration.

CYP3A Substrates:

Olaparib is a moderate inhibitor of CYP3A and may increase the plasma concentrations of drugs metabolized by CYP3A (e.g., simvastatin, midazolam).

Monitor closely for adverse reactions associated with these substrate drugs when co-administered.

IX. Use in Specific Populations

Pregnant Women: May cause fetal harm. Advise pregnant women of the potential risk to the fetus. Lactation: It is recommended to discontinue breastfeeding during treatment and for one month following the last dose.

Pediatric Patients: Safety and efficacy have not been established.

Geriatric Patients: In patients aged 65 years and older, no overall differences in safety were observed compared to younger patients.

Patients with Hepatic/Renal Impairment:

Hepatic Impairment: No dose adjustment is required for patients with mild hepatic impairment. For patients with moderate (Child-Pugh B) hepatic impairment, the recommended dose is 200 mg twice daily. For patients with severe (Child-Pugh C) hepatic impairment, data are limited, and caution is advised. 

Renal Impairment: No dose adjustment is required for patients with mild renal impairment (creatinine clearance 51–80 mL/min). For patients with moderate renal impairment (creatinine clearance 31–50 mL/min), the recommended dose is 200 mg twice daily. Use is not recommended for patients with severe renal impairment (creatinine clearance ≤30 mL/min) or those requiring dialysis.

X. Overdosage

Symptoms: An exacerbation of adverse reactions is expected.

Management: Supportive care should be provided, and treatment should be symptomatic, including close monitoring of blood counts.

XI. Clinical Pharmacology

Pharmacokinetics: Olaparib is rapidly absorbed following oral administration, reaching peak plasma concentrations approximately 1–3 hours after dosing. It is primarily metabolized in vivo via CYP3A4/5. Fecal excretion is the primary route of elimination.

XII. Patient Counseling Information

1.  Genetic Testing: Understand the necessity of undergoing BRCA or HRR gene testing prior to initiating treatment.

2.  Adherence to Prescribing Instructions: Do not arbitrarily adjust the dose or discontinue the medication.

3.  Hematologic Monitoring: Understand the importance of regular complete blood count monitoring for the early detection of MDS/AML.

4.  Pulmonary Symptoms: Immediately report any new or worsening respiratory symptoms.

5.  Contraception Requirements: Patients of reproductive potential must understand and strictly adhere to contraception requirements.

6.  Disclosure of Medication History: Inform your physician of all other medications you are currently taking.

Finally, a reminder: Please strictly follow the specific instructions provided by your treating physician and pharmacist. If you have any questions or experience any discomfort during treatment, please communicate immediately with your medical team.