PARP Inhibitor Clinical Trials in the UK 2026 — Find Active Studies
PARP inhibitors were one of the first truly personalised cancer treatments, exploiting a specific weakness in cancer cells with DNA repair defects. Since the approval of olaparib in 2014, these drugs have transformed treatment for ovarian, breast, prostate, and pancreatic cancers — particularly in patients with BRCA mutations. UK clinical trials continue to expand PARP inhibitor use into earlier disease stages, new combinations, and broader patient populations.
How PARP Inhibitors Work
Cancer cells with BRCA mutations have a defective DNA repair pathway (homologous recombination). PARP inhibitors block the alternative DNA repair pathway, creating "synthetic lethality" — the cancer cell cannot repair its DNA and dies. Normal cells survive because they still have functional BRCA pathways.
Beyond just inhibiting the PARP enzyme, drugs like olaparib and talazoparib "trap" PARP proteins on DNA, creating toxic roadblocks that are lethal to cancer cells with DNA repair defects.
While BRCA mutations are the classic indication, PARP inhibitors also work in tumours with other DNA repair defects (HRD-positive), including those with PALB2, RAD51, ATM, and CHEK2 mutations. Trials are broadening eligibility beyond BRCA.
Exciting trials combine PARP inhibitors with immunotherapy, anti-angiogenic drugs, PI3K inhibitors, and other targeted therapies. These combinations aim to expand benefit to patients without BRCA mutations.
PARP Inhibitor Drugs in UK Trials
- Olaparib (Lynparza) — The first and most widely studied PARP inhibitor. Approved for ovarian, breast, prostate, and pancreatic cancer. Trials testing in earlier stages and new combinations.
- Niraparib (Zejula) — Approved for ovarian cancer maintenance. Trials combining with immunotherapy (topacio) and in earlier disease stages.
- Rucaparib (Rubraca) — Approved for ovarian cancer. Trials in prostate cancer and other solid tumours with HRD.
- Talazoparib (Talzenna) — The most potent PARP trap. Approved for BRCA+ breast cancer. Trials in prostate cancer and combinations.
- Veliparib — Investigational PARP inhibitor in numerous combination trials with chemotherapy and radiation.
Who Is Eligible?
PARP inhibitor trial eligibility has broadened significantly:
- BRCA1/BRCA2 mutation carriers — The clearest eligibility criterion. Both germline (inherited) and somatic (tumour-only) mutations qualify
- HRD-positive tumours — Homologous recombination deficiency detected by genomic scar testing (Myriad myChoice, FoundationOne)
- Prior treatment — Some trials are for newly diagnosed patients (adjuvant/maintenance), others for relapsed disease
- Biomarker testing — Most trials require genetic testing results before enrolment. Ask your oncologist about genomic profiling
Did you know? About 1 in 8 ovarian cancers and 5-10% of breast cancers have BRCA mutations. If you haven't been tested, ask your oncologist — this testing is increasingly available on the NHS and can open up PARP inhibitor trial options.
What to Expect
- PARP inhibitors are taken as oral tablets — usually twice daily at home (no hospital visits for infusions)
- Treatment continues for as long as it's working and side effects are manageable (often 2+ years)
- Common side effects: nausea, fatigue, anaemia, low platelets, and taste changes
- Regular blood tests (every 1-4 weeks initially) to monitor blood counts
- Scans every 8-12 weeks to assess response
- Rare but important: risk of MDS/AML (bone marrow cancer) — long-term monitoring required
- Your quality of life on PARP inhibitors is often much better than on chemotherapy
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