ZEJULA inhibits PARP1 and PARP2, leading to cancer cell death in preclinical studies1

The clinical significance of in vitro studies is unknown.
Mechanism of action statements are not meant to imply clinical efficacy.

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Single-Strand Break

PARP inhibition interferes with DNA repair, leading to accumulation of single-strand breaks (SSBs).1,2

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Double-Strand Break

SSBs become double-strand breaks (DSBs), which are not repaired due to deficient DNA repair pathways present in many ovarian tumors.3

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Cell Death

Persistent DSBs that cannot be repaired lead to programmed cell death.3

ZEJULA is an inhibitor of poly (ADP-ribose) polymerase (PARP) enzymes, PARP1 and PARP2, which play a role in DNA repair. In vitro studies suggest that ZEJULA’s cytotoxic effects may involve inhibition of PARP enzymatic activity and increased formation of PARP-DNA complexes resulting in DNA damage, apoptosis, and cell death.1

Preclinical studies suggest the activity of PARP inhibitors depends on tumor exposure and subsequent PARP1/2 inhibition.4

  • Tumor cells carrying a BRCA mutation have been shown to be significantly more sensitive to PARP inhibition than tumors that do not carry a BRCA mutation5
  • It is hypothesized that in tumors without a BRCA mutation, PARP inhibitors may need to achieve higher tumor concentrations for effect5

The clinical significance of in vitro studies is unknown. Mechanism of action statements are not meant to imply clinical efficacy.

ZEJULA has high bioavailability and extensive tissue distribution, as well as a long half-life1

Highly Bioavailable1

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Absolute bioavailability

Long Half-life1

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Mean half-life, allowing for once-daily dosing

Extensive Tissue Distribution1

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1220 L (Vd/F)

Concentrates in tissue


  1. ZEJULA (niraparib) Tablets. Prescribing Information. GSK; 2023.

  2. Satoh MS, Lindahl T. Nature. 1992;356(6367):356-358.

  3. Rein ID, Landsverk KS, Micci F, Patzke S, Stokke T. Cell Cycle. 2015;14(20):3248-3260.

  4. Ricks TK, Chiu HJ, Ison G, et al. Front Oncol. 2015;5:222. doi:10.3389/fonc.2015.00222

  5. Farmer H, McCabe N, Lord CJ, et al. Nature. 2005;434(7035):917-921.