**3.1 Dosing, administration, and drug interactions**

PARP inhibitors are available in oral dosing forms (tablet or capsule). The starting dose of olaparib is at 300 mg twice daily and rucaparib at 600 mg twice daily [51, 54]. Niraparib is the only once-daily PARPi with an individualized starting dose based on weight (< or ≥ 77 kg) and/or platelet count (< or ≥ 150,000/mcl) at 200 mg or 300 mg for first-line maintenance advanced EOC indication [47, 48] and 300 mg once daily for all other indications [47]. Of note, approximately 15% of patients in the NOVA study weighed <58 kg and the incidence of grade 3 or 4 adverse events was higher in the patients with lower body weight (<58 kg). As such, a starting dose of niraparib 200 mg for patients weighing less than 58 kg may be considered [48].

Olaparib may be dose adjusted to 200 mg twice daily in patients with moderate renal impairment [21, 51] and the use of olaparib is not recommended in patients with severe renal impairment [21] whereas niraparib may be dose adjusted to a starting dose of 200 mg once daily for moderate hepatic impairment [47]. No starting dose adjustment is recommended for patients with mild to moderate renal or hepatic impairment for rucaparib [52, 53] but the use of rucaparib in patients with severe renal or hepatic impairment has not been studied [55].

The coadministration of food or high-fat meal does not have clinically significant impact on pharmacokinetics, thus PARPis can be taken with or without food [21, 47, 48, 51, 54, 55].

Based on *in vitro* studies evidence, the concomitant use of strong or moderate CYP3A inhibitors or inducers with olaparib is not recommended [21, 51]. If the concomitant use of a CYP3A inhibitor cannot be avoided, olaparib dose shall be dose reduced [51]. Although no dose adjustment is needed for rucaparib, caution is recommended for concomitant administration with strong CYP3A and P-glycoprotein (P-gp) inhibitors [54, 55]. In contrast, niraparib is metabolized via carboxylesterases (CEs) catalyzed amide hydrolysis instead of CYP3A enzymes. There is low likelihood of clinically relevant interactions with other drugs and no dose adjustment is required [47, 48].
