PF-2545920

PF-2545920 is an inhibitor of phosphodiesterase 10A (PDE10A) with IC50 value of 0.37nM [1].

PDE10A is highly expressed in the medium spiny neurons of the striatum and regulates both cGMP and cAMP. The PDE10A inhibitors are believed to regulate cyclic nucleotide signaling in the cortices-triatothalamic circuit. Previous inhibitors of PDE have potential therapeutic utility but also have potential safety risks due to off-target PDE inhibition. Thereby PF-2545920 is developed as a more selective inhibitor. PF-2545920 is shown to be efficacious both in vitro and in vivo with improved penetration in CNS. It has excellent in vivo efficacy in neurochemical elevation of cyclic nucleotides and in models predictive of antipsychotic activity. Administration of PF-2545920 to mice can cause increase in striatal cGMP with the minimal effective dose at about 1mg/kg [1].

References:
[1] Verhoest PR, Chapin DS, Corman M, Fonseca K, Harms JF, Hou X, Marr ES, Menniti FS, Nelson F, O'Connor R, Pandit J, Proulx-Lafrance C, Schmidt AW, Schmidt CJ, Suiciak JA, Liras S. Discovery of a novel class of phosphodiesterase 10A inhibitors and identification of clinical candidate 2-[4-(1-methyl-4-pyridin-4-yl-1H-pyrazol-3-yl)-phenoxymethyl]-quinoline (PF-2545920) for the treatment of schizophrenia. J Med Chem. 2009 Aug 27;52(16):5188-96.

Discovery of a novel class of phosphodiesterase 10A inhibitors and identification of clinical candidate 2-[4-(1-methyl-4-pyridin-4-yl-1H-pyrazol-3-yl)-phenoxymethyl]-quinoline (PF-2545920) for the treatment of schizophrenia.[Pubmed:19630403]

J Med Chem. 2009 Aug 27;52(16):5188-96.

By utilizing structure-based drug design (SBDD) knowledge, a novel class of phosphodiesterase (PDE) 10A inhibitors was identified. The structure-based drug design efforts identified a unique "selectivity pocket" for PDE10A inhibitors, and interactions within this pocket allowed the design of highly selective and potent PDE10A inhibitors. Further optimization of brain penetration and drug-like properties led to the discovery of 2-[4-(1-methyl-4-pyridin-4-yl-1H-pyrazol-3-yl)-phenoxymethyl]-quinoline (PF-2545920). This PDE10A inhibitor is the first reported clinical entry for this mechanism in the treatment of schizophrenia.

Phosphodiesterase 10A inhibitor, MP-10 (PF-2545920), produces greater induction of c-Fos in dopamine D2 neurons than in D1 neurons in the neostriatum.[Pubmed:26256420]

Neuropharmacology. 2015 Dec;99:379-86.

Studies described here tested the hypothesis that phosphodiesterase 10A inhibition by a selective antagonist, MP-10, activates the dopamine D2 receptor expressing medium spiny neurons to a greater extent than the D1 receptor expressing neurons. We used regional pattern of c-Fos induction in the neostriatal subregions of rodents and direct assessment of D1-positive and -negative neurons in the DRd1a-tdTomato mice for the purpose. MP-10 (1, 3, 10 or 30 mg/kg, PO) dose-dependently increased c-Fos immunopositive nuclei in all regions of neostriatum. However, the effect was statistically greater in the dorsolateral striatum, a region known to be activated preferentially by the D2 antagonism, than the D1-activated dorsomedial striatum. The D2 antagonist, haloperidol (0.3, 1, or 3 mg/kg, PO) produced an identical, regional pattern of c-Fos induction favoring the dorsolateral striatum of the rat. In contrast, the D1 agonist, SKF82958 (0.5, 1, or 2 mg/kg, PO), induced greater expression of c-Fos in the dorsomedial striatum. The C57Bl/6 mouse also showed regionally preferential c-Fos activation by haloperidol (2 mg/kg, IP) and SKF82858 (3 mg/kg, IP). In the Drd1a-tdTomato mice, MP-10 (3 or 10 mg/kg, IP) increased c-Fos immunoreactivity in both types of neurons, the induction was greater in the D1-negative neurons. Taken together, both the regional pattern of c-Fos induction in the striatal sub-regions and the greater induction of c-Fos in the D1-negative neurons indicate that PDE10A inhibition produces a small but significantly greater activation of the D2-containing striatopallidal pathway.