Talazoparib (BMN 673)

BMN-673 selectively binds to PARP and prevents PARP-mediated DNA repair of single strand DNA breaks via the base-excision repair pathway. This enhances the accumulation of DNA strand breaks, promotes genomic instability and eventually leads to apoptosis. BMN 673 selectively kills cancer cells with BRCA-1 or BRCA-2 mutations. BMN 673 demonstrates single-agent cytotoxicityin BRCA-1 mutant (MX-1, IC50 = 0.3 nM) and BRCA-2 mutant cells (Capan-1, IC50 = 5 nM). In contrast, in MRC-5 normal human fibroblastand other tumor cell lines with wild-type BRCA-1 and BRCA-2 genes, IC50 of BMN 673 ranges between 90 nM and 1.9 μM. ^[1]

In cultured human cancer cells, BMN 673 also significantly enhances the cytotoxic efficacy of both Temozolomide and SN-38. Off-target molecular screening did not identify significant non-specific activity for this class of PARP inhibitors. ^[2]

In rat pharmacokinetic studies, BMN 673 displays >50% oralbioavailability and pharmacokinetic properties that enable singledaily dosing. In MX-1 xenograft tumor model studies, daily oral dosingof BMN 673 significantly enhances the antitumor effects ofcytotoxic therapies in a dose-dependent manner. ^[2]

• Cell lines

  MDA-MB-436 cells

• Concentrations

  10 uM

• Incubation Time

  7 days

• Method

  Cells were treated with increasing doses of talazoparib for 7 days and subjected to cell viability assays to derive IC50 values.

• Animal Models

  MX-1 model (BRCA-1 deficient)

• Dosages

  0.33 mg/kg/day, once daily

• Administration

  Oral