BMN 673

Description

Talazoparib (BMN 673) is a novel PARP inhibitor with IC50 of 0.58 nM in a cell-free assay. It is also a potent inhibitor of PARP-2, but does not inhibit PARG and is highly sensitive to PTEN mutation. Phase 3.

Features

Most potent and selective PARPi reported thus far.

In vitro

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. 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.

In vivo

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.

Uses

BMN 673 is a pyrrolopyrazine derivative and anpoly (ADP-ribose) polymerase (PARP) inhibitor for patients with advanced or recurrent solid tumors such as ovarian and breast cancer.

Biological Activity

bmn673 is a potent and selective parp1/2 inhibitor with ki of 1.2 and 0.9 nm, respectively 1. it had no effect on panels of 72 receptors, ion channels, and enzymes 1. bmn673 showed ic50 value of 0.57 nm in enzymatic assay of parp1 1. in in vitro assay, it exhibited greater potency than other existing parp inhibitors, such as veliparib, rucaparib, and olaparib 2. it is also much more potent at trapping parp-dna complexes than other parp inhibitors 3.bmn673 has shown anti-tumor activity both in vitro and in vivo. it inhibited proliferation of tumor cells and xenografts with defects in homologous recombination 1. the combination of bmn673 and dna-damaging agents demonstrated synergistic anti-tumor effects 1. in addition, study showed that the expression levels of dna repair proteins and status of pi3k pathway predict response to bmn673 in small cell lung cancer 4.bmn673 is currently under investigation in multiple

Synthesis

1373329-52-2

1207456-01-6

Methyl (2S,3S)-7-fluoro-2-(4-fluorophenyl)-3-(1-methyl-1H-1,2,4-triazol-5-yl)-4-oxo-1,2,3,4-tetrahydroquinoline-5-carboxylate (36 g, 90.37 mmol) was used as a raw material, which was added with ethanol (450 mL) and 50% hydrazine hydrate (28.96 g, 452 mmol) to the reactor and heated to reflux for 3 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product was sequentially washed with water, filtered, and then washed with ethanol, and finally purified by recrystallization to afford the target compound (8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one (tarazolba, white solid, 31 g , 90.2% yield). The product was 99.5% pure by HPLC. m/z LC-MS (ESI): 381 (M + 1)+. 1H-NMR (400 MHz, DMSO-d6) δ (ppm): 3.68 (s, 3H), 4.99-5.06 (m, 2H), 6.92-6.96 (m, 1H), 7.08-7.11 (m, 1H). 7.16-7.20 (t, J = 8.8Hz, 2H), 7.49-7.53 (m, 2H), 7.75 (s, 1H), 7.83 (s, 1H), 12.35 (s, 1H).

Enzyme inhibitor

This novel, orally bioavailable poly(ADP-ribose) polymerase, or PARP, inhibitor (FW = 380.35 g/mol; CAS 1207456-01-6), also known as (8S,9R)- 5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro- 2H-pyrido[4,3,2-de]phthalazin-3(7H)-one, targets PARP-mediated DNA repair (IC50 = 0.58 nM) of single-strand DNA breaks by the base-excision repair pathway. By enhancing the accumulation of DNA strand breaks, BMN 673 promotes genomic instability, eventually leading to apoptosis. BMN 673 exhibits selective anti-tumor cytotoxicity and elicits DNA repair biomarkers at much lower concentrations than earlier generation PARP1/2 inhibitors, including olaparib, rucaparib and veliparib. BMN 673 shows remarkable anti-tumor activity in vivo, with strong action against xenografted tumors carrying defects in DNA repair due to BRCA mutations or PTEN deficiency. Synergistic or additive anti-tumor effects are observed, when BMN 673 was combined with temozolomide, SN38 or platinum drugs.

in vivo

target

PARP

IC 50

PARP2: 0.87 nM (Ki); PARP1: 1.2 nM (Ki)

Background

Talazoparib is a potent, selective PARP inhibitor with an IC50 value for PARP1 of 0.57 nM. It can inhibit both PARP1 and PARP2, but not PARG. Talazoparib selectively targets tumor cells with BRCA1, BRCA2, and PTEN gene mutations. It is effective in inducing antitumor activity in vivo in xenografted tumors from mice.

References

1. shen y, rehman fl, feng y et al. bmn 673, a novel and highly potent parp1/2 inhibitor for the treatment of human cancers with dna repair deficiency. clin cancer res 2013; 19: 5003-5015.2. cardnell rj, byers la. proteomic markers of dna repair and pi3k pathway activation predict response to the parp inhibitor bmn 673 in small cell lung cancer--response. clin cancer res 2014; 20: 2237.3. murai j, huang sy, renaud a et al. stereospecific parp trapping by bmn 673 and comparison with olaparib and rucaparib. mol cancer ther 2014; 13: 433-443.4. cardnell rj, feng y, diao l et al. proteomic markers of dna repair and pi3k pathway activation predict response to the parp inhibitor bmn 673 in small cell lung cancer. clin cancer res 2013; 19: 6322-6328.