Pre-clinical Characterization of Absorption, Distribution, Metabolism and Excretion Properties of TAK-063

The Impact of P-Glycoprotein on CNS Drug Efflux and Variability in Response

Resistance against CNS drugs may arise from various mechanisms, with limited drug penetration across the blood-brain barrier (BBB) being a significant contributing factor. The BBB employs efflux transporters like P-glycoprotein (P-gp) to safeguard the brain by removing toxins and xenobiotics, however, P-gp also pumps out therapeutic drugs, and its upregulation in disease states can contribute to variability in drug response. While inhibiting P-gp to prevent drug efflux seems appealing, it could lead to toxicity since P-gp is also important for expulsion of toxins from the brain. This necessitates the incorporation of P-gp substrate liability assessment into early drug discovery stages using appropriate experimental approaches. Therefore, this review aims to draw interest in this crucial area by analyzing the existing research on P-gp's impact on brain distribution of major CNS drugs and exploring the detection methods for identifying P-gp substrates. By identifying confirmed P-gp substrates and evaluating effective detection methods, this work emphasizes the continued importance of monitoring P-gp-mediated CNS drug efflux out of the brain tissue. This knowledge can empower clinicians to anticipate potential treatment inefficacy and guide therapeutic decision-making, ultimately leading to improved patient treatment outcomes.

Inhibition of phosphodiesterase 10A mitigates neuronal injury by modulating apoptotic pathways in cold-induced traumatic brain injury

Brain injury develops from a complex series of pathophysiological phases, resulting in acute necrotic or delayed apoptotic cell death after traumatic brain injury (TBI). Inhibition of apoptotic cell death is critical for the treatment of acute neurodegenerative disorders, such as TBI. Here, we investigated the role of phosphodiesterase 10A (PDE10A) in the development of neuronal injury, particularly in apoptotic cell death. Using the PDE10A inhibitor TAK-063, we found that PDE10A inhibition is associated with decreased brain injury, brain swelling, and blood brain barrier disruption 48 h after cold-induced TBI. Furthermore, a particularly notable result was observed with 3 mg/kg TAK-063, which reduced disseminated neuronal injury. Protein abundance analysis revealed that PDE10A inhibition activates survival kinases AKT and ERK-1/-2, which were associated with the decreased activation of MMP-9 and PTEN. Additionally, iNOS and nNOS levels significantly reduced in the TAK-063 group, playing roles in inflammation and apoptosis. A planar surface immunoassay was performed for in-depth analyses of the apoptotic signaling pathways. We observed that inhibition of PDE10A resulted in the decreased expression of TNFRSF1A, TNFRSF10B, and TNFRSF6 receptors, particularly inducing apoptotic cell death. Moreover, these findings correlated with reduced levels of pro-apoptotic proteins, including PTEN, p27, Cytochrome-c, cleaved Caspase-3, Bad, and p53. Interestingly, TAK-063 treatment reduced levels of anti-apoptotic proteins or enzymes, including XIAP, Claspin, and HIF1α, without affecting Bcl-x, MCL-1, SMAC, HO-1, HO-2, HSP27, HSP60, and HSP70. The findings suggest that PDE10A regulates cellular signaling predominantly pro-apoptotic pathways, and inhibition of this protein is a promising approach for the treatment of acute brain injury.

Phosphodiesterase 10A deactivation induces long-term neurological recovery, Peri-infarct remodeling and pyramidal tract plasticity after transient focal cerebral ischemia in mice

The phosphodiesterase (PDE) superfamily comprises enzymes responsible for the cAMP and cGMP degradation to AMP and GMP. PDEs are abundant in the brain, where they are involved in several neuronal functions. High PDE10A abundance was previously observed in the striatum; however its consequences for stroke recovery were unknown. Herein, we evaluated the effects of PDE10A deactivation by TAK-063 (0.3 or 3 mg/kg, initiated 72 h post-stroke) in mice exposed to intraluminal middle cerebral artery occlusion. We found that PDE10A deactivation over up to eight weeks dose-dependently increased long-term neuronal survival, angiogenesis, and neurogenesis in the peri-infarct striatum, which represents the core of the middle cerebral artery territory, and reduced astroglial scar formation, whole brain atrophy and, more specifically, striatal atrophy. Functional motor-coordination recovery and the long-distance plasticity of pyramidal tract axons, which originate from the contralesional motor cortex and descend through the contralesional striatum to innervate the ipsilesional facial nucleus, were enhanced by PDE10A deactivation. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed a set of dopamine receptor-related and neuronal plasticity-related PDE10A targets, which were elevated (e.g., protein phosphatase-1 regulatory subunit 1B) or reduced (e.g., serine/threonine protein phosphatase 1α, β-synuclein, proteasome subunit α2) by PDE10A deactivation. Our results identify PDE10A as a therapeutic target that critically controls post-ischemic brain tissue remodeling and plasticity.

Translational Development Strategies for TAK-063, a Phosphodiesterase 10A Inhibitor

BACKGROUND

TAK-063 is an inhibitor of phosphodiesterase 10A (PDE10A), an enzyme highly expressed in medium spiny neurons of the striatum. PDE10A hydrolyzes both cyclic adenosine monophosphate and cyclic guanosine monophosphate and modulates dopamine signaling downstream of receptor activation in both direct and indirect pathways of the striatum. TAK-063 exhibited antipsychotic-like effects in animal models; however, the translatability of these models to the clinical manifestations of schizophrenia and the meaningfulness for new targets such as PDE10A has not been established.

METHODS

The TAK-063 phase 1 program included a comprehensive translational development strategy with the main objective of determining whether the antipsychotic-like pharmacodynamic effects seen in nonclinical models would translate to human subjects. To evaluate this objective, we conducted a single-rising dose study (84 healthy subjects), a positron emission tomography (PET) study (12 healthy subjects), a functional magnetic resonance imaging blood oxygen level-dependent (BOLD) study (27 healthy subjects), and a multiple-rising dose study that included people with schizophrenia (30 healthy Japanese subjects and 47 subjects with stable schizophrenia). In addition, assessments of cognition and electroencephalography (27 healthy subjects and 47 subjects with stable schizophrenia) were included.

RESULTS

PDE10A engagement by TAK-063 was verified with a novel PET radiotracer for use in primates and humans. TAK-063 showed favorable pharmacokinetic and safety profiles in humans, and TAK-063 reduced ketamine-induced changes in electroencephalography and BOLD signaling in animal models and healthy human subjects. In addition, analogous effects on cognition were observed in animal models and human subjects.

CONCLUSIONS

Overall, the phase 1 results showed some consistent evidence of antipsychotic activity. This translational strategy may be valuable for the future development of novel therapeutic approaches, even when relevant nonclinical models are not available.