PARP is an essential protein found in the DNA repair pathway, which helps amend breakages in single-stranded DNA. PARP (poly – ADP ribose polymerase) inhibitors are targeted cancer drugs that work by preventing the proteins from carrying out their function thus consequently leading to double-strand breaks as the number of damaged single-stranded DNA accumulates (NHS England, 2024). Disrupting DNA replication can prevent cancer cells from dividing and cause cell death.

PARP inhibitors to treat breast cancer

The most used PARP inhibitor in the NHS for people with primary breast cancer is Olaparib, which is taken orally. For patients with breast cancer, PARP inhibitors are used to target BRCA 1 and BRCA 2 genes - two inherited altered genes that increase the risk of breast cancer (Breast Cancer Now, 2022). Cancer cells that already contain faulty BRCA genes are less able to repair themselves, therefore using PARP inhibitors will further decrease their repair system and eventually lead to apoptosis (Cancer Research UK, 2021). PARP inhibitors are also widely used to treat ovarian cancer.

What are the side effects of taking PARP inhibitors?

• Hematologic toxicities including anaemia and thrombocytopenia 

• Tiredness

• Nausea and Vomiting

• Dizziness

• Diarrhoea

• Bruising and Bleeding 

(Breast Cancer Now, 2022) 

Overall, the future of PARP inhibitors seems quite promising as there is continuous research into the use of PARP inhibitors and how the adverse effects listed above, as well as PARP inhibitor resistance, can be limited. In addition, the ongoing trials, of which some involve the combination of both PARP inhibitors and other types of treatment such as chemotherapy and radiotherapy, is essential to find out whether this treatment is effective for other types of cancer such as: prostate, lung and pancreatic cancer. Such developments in research and medical interventions to treat cancer could ultimately increase the availability of different treatment options thus improving patient outcomes (Cancer Research UK, 2021).

Written by Varsana

Moderated by Adelene

References