Talazoparib (Specialist drug)

How it works

It inhibits poly(ADP-ribose) polymerase (PARP) enzymes and traps PARP on DNA, so cancer cells with defective homologous-recombination repair (such as BRCA-mutated cells) cannot repair DNA damage and undergo cell death.

Prescribing in practice

• Myelosuppression, particularly anaemia, is common and can be severe, so blood counts must be checked before and regularly during treatment with dose adjustment or interruption as needed.
• Rare but serious myelodysplastic syndrome and acute myeloid leukaemia have been reported with PARP inhibitors.
• It is a P-glycoprotein and BCRP substrate, so interacting medicines should be reviewed against the SPC.

Monitoring

Monitor the full blood count before starting and regularly throughout treatment, watching for persistent or unexplained cytopenias.

Counselling the patient

• Report unusual tiredness, bruising, bleeding, or signs of infection.
• Use effective contraception during and after treatment as advised, as this drug can harm a developing baby.
• Take the capsules as directed and attend all blood-test appointments.

Evidence & guidelines

Efficacy in BRCA-mutated advanced breast cancer was shown in a randomised phase 3 trial, with use reflected in NICE guidance.