Efficacy and safety of TV-46000, a long-acting, subcutaneous, injectable formulation of risperidone, for schizophrenia: a randomised clinical trial in the USA and Bulgaria.

BACKGROUND: TV-46000 is a long-acting, subcutaneous, antipsychotic agent that combines risperidone and an innovative, copolymer-based drug delivery technology in a suspension that was approved in April, 2023 for subcutaneous use. The aim of the phase 3 Risperidone Subcutaneous Extended-release (RISE) study was to evaluate the efficacy of TV­46000 in schizophrenia. METHODS: The RISE study consisted of two treatment stages: a 12-week, open-label stabilisation phase with oral risperidone (stage 1), and an open-ended, randomised, double-blind, placebo-controlled, relapse-prevention phase with subcutaneous TV-46000 (stage 2) done at 69 clinical sites across the USA and Bulgaria. Patients diagnosed with schizophrenia more than 1 year before screening by DSM-5 criteria and confirmed at screening by the Structured Clinical Interview for DSM-5 and who had at least one relapse within 24 months before screening were eligible for enrolment. Patients who were outpatients and stabilised in stage 1 continued to stage 2 and were randomly assigned 1:1:1 by a computer-generated randomisation list to receive either subcutaneous TV-46000 once monthly, TV-46000 once every 2 months, or placebo until relapse, early discontinuation, or the study was stopped because the prespecified stopping criterion of at least 90 relapse events was met. The primary endpoint was time to impending relapse of the intention-to-treat patient population in stage 2. This study is registered with ClinicalTrials.gov, number NCT03503318, and is complete. FINDINGS: The study enrolled the first patient on June 1, 2018, and the last patient completed on Dec 3, 2020. 1267 patients were screened, 863 enrolled, and 544 (male, n=332 [61%], female, n=212 [39%]; mean [SD] age, 49·3 [10·98] years; Black or African American, n=322 [59%]; White, n=206 [38%]; Asian, n=7 [1%]; Native Hawaiian or other Pacific Islander, n=2 [<1%]; race not reported, n=3 [<1%]; other race, n=4 [<1%]; Hispanic or Latinx, n=117 [22%]) randomly assigned to subcutaneous TV-46000 once monthly (n=183), TV-46000 once every 2 months (n=180), or placebo (n=181). Time to impending relapse was significantly prolonged by 5·0 times with TV-46000 once monthly (hazard ratio, 0·200 [95% CI 0·109-0·367]; p<0·0001) and by 2·7 times with TV-46000 once every 2 months (0·375 [0·227-0·618]; p<0·0001) versus placebo. Most frequently reported treatment-related adverse events (ie, ≥5% of patients in either TV-46000 group) that occurred more often in patients receiving TV-46000 (once monthly or once every 2 months) versus placebo were injection site nodules (7% for TV-46000 once monthly, 7% for TV-46000 once every 2 months, 3% for placebo), weight increased (4%, 6%, 2%, respectively), and extrapyramidal disorder (5%, 3%, 0% respectively). Serious adverse events were reported for eight (4%) patients in the TV-46000 once-monthly group, ten (6%) patients in the TV-46000 once-every-2-months group, and 14 (8%) patients in the placebo group. The safety profile of TV-46000 was consistent with other approved formulations of risperidone. No new safety signals were identified. INTERPRETATION: In patients with schizophrenia, subcutaneous TV-46000 once monthly and once every 2 months significantly delayed impending relapse versus placebo. TV-46000 is an effective long-acting, subcutaneous, antipsychotic agent treatment option in adult patients with schizophrenia, with a favourable benefit-risk profile. FUNDING: Teva Branded Pharmaceutical Products R&D.

Population Pharmacokinetic Modeling and Simulation of TV-46000: A Long-Acting Injectable Formulation of Risperidone.

TV-46000 is a long-acting subcutaneous antipsychotic that uses a novel copolymer drug delivery technology in combination with a well-characterized molecule, risperidone, that is in clinical development as a treatment for schizophrenia. A population pharmacokinetic (PPK) modeling and simulation approach was implemented to identify TV-46000 doses and dosing schedules for clinical development that would provide the best balance between clinical efficacy and safety. The PPK model was created by applying pharmacokinetic data from a phase 1 study of 97 patients with a diagnosis of schizophrenia or schizoaffective disorder who received either single or repeated doses of TV-46000. The PPK model was used to characterize the complex release profile of the total active moiety (TAM; the sum of the risperidone and 9-OH risperidone concentrations) concentration following subcutaneous injections of TV-46000. The PK profile was best described by a double Weibull function of the in vivo release rate and by a 2-compartment disposition and elimination model. Simulations were performed to determine TV-46000 doses and dosing schedules that maintained a median profile of TAM concentrations similar to published TAM exposure following oral risperidone doses that have been correlated to a 40% to 80% dopamine-D2 receptor occupancy therapeutic window. The simulations showed that therapeutic dose ranges for TV-46000 are 50 to 125 mg for once-monthly and 100 to 250 mg for the once every 2 months regimens. This PPK model provided a basis for prediction of patient-specific exposure and dopamine-D2 receptor occupancy estimates to support further clinical development and dose selection for the phase 3 studies.

Cognitive disturbances in the cuprizone model of multiple sclerosis.

Cognitive problems frequently accompany neurological manifestations of multiple sclerosis (MS). However, during screening of preclinical candidates, assessments of behaviour in mouse models of MS typically focus on locomotor activity. In the present study, we analysed cognitive behaviour of 9 to 10-week-old female C57Bl/6J mice orally administered with the toxin cuprizone that induces demyelination, a characteristic feature of MS. Animals received 400 mg/kg cuprizone daily for 2 or 4 weeks, and their performance was compared with that of vehicle-treated mice. Cuprizone-treated animals showed multiple deficits in short touchscreen-based operant tasks: they responded more slowly to visual stimuli, rewards and made more errors in a simple rule-learning task. In contextual/cued fear conditioning experiments, cuprizone-treated mice showed significantly lower levels of contextual freezing than vehicle-treated mice. Diffusion tensor imaging showed treatment-dependent changes in fractional anisotropy as well as in axial and mean diffusivities in different white matter areas. Lower values of fractional anisotropy and axial diffusivity in cuprizone-treated mice indicated developing demyelination and/or axonal damage. Several diffusion tensor imaging measurements correlated with learning parameters. Our results show that translational touchscreen operant tests and fear conditioning paradigms can reliably detect cognitive consequences of cuprizone treatment. The suggested experimental approach enables screening novel MS drug candidates in longitudinal experiments for their ability to improve pathological changes in brain structure and reverse cognitive deficits.

ADNP Plays a Key Role in Autophagy: From Autism to Schizophrenia and Alzheimer's Disease.

Activity-dependent neuroprotective protein (ADNP), discovered in our laboratory in 1999, has been characterized as a master gene vital for mammalian brain formation. ADNP de novo mutations in humans result in a syndromic form of autism-like spectrum disorder (ASD), including cognitive and motor deficits, the ADNP syndrome (Helsmoortel-Van Der Aa). One of the most important cellular processes associated with ADNP is the autophagy pathway, recently discovered by us as a key player in the pathophysiology of schizophrenia. In this regard, given the link between the microtubule and autophagy systems, the ADNP microtubule end binding protein motif, namely, the neuroprotective NAP (NAPVSIPQ), was found to enhance autophagy while protecting microtubules and augmenting ADNP's association with both systems. Thus, linking autophagy and ADNP is proposed as a major target for intervention in brain diseases from autism to Alzheimer's disease (AD) and our findings introduce autophagy as a possible novel target for treating schizophrenia.

New horizons in schizophrenia treatment: autophagy protection is coupled with behavioral improvements in a mouse model of schizophrenia.

Autophagy plays a key role in the pathophysiology of schizophrenia as manifested by a 40% decrease in BECN1/Beclin 1 mRNA in postmortem hippocampal tissues relative to controls. This decrease was coupled with the deregulation of the essential ADNP (activity-dependent neuroprotector homeobox), a binding partner of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 ß) another major constituent of autophagy. The drug candidate NAP (davunetide), a peptide fragment from ADNP, enhanced the ADNP-LC3B interaction. Parallel genetic studies have linked allelic variation in the gene encoding MAP6/STOP (microtubule-associated protein 6) to schizophrenia, along with altered MAP6/STOP protein expression in the schizophrenic brain and schizophrenic-like behaviors in Map6-deficient mice. In this study, for the first time, we reveal significant decreases in hippocampal Becn1 mRNA and reversal by NAP but not by the antipsychotic clozapine (CLZ) in Map6-deficient (Map6(+/-)) mice. Normalization of Becn1 expression by NAP was coupled with behavioral protection against hyperlocomotion and cognitive deficits measured in the object recognition test. CLZ reduced hyperlocomotion below control levels and did not significantly affect object recognition. The combination of CLZ and NAP resulted in normalized outcome behaviors. Phase II clinical studies have shown NAP-dependent augmentation of functional activities of daily living coupled with brain protection. The current studies provide a new mechanistic pathway and a novel avenue for drug development.

NAP (davunetide) enhances cognitive behavior in the STOP heterozygous mouse--a microtubule-deficient model of schizophrenia.

NAP (generic name, davunetide) is an active fragment of activity-dependent neuroprotective protein (ADNP). ADNP-/- embryos exhibit CNS dysgenesis and die in utero. ADNP+/- mice survive but demonstrate cognitive dysfunction coupled with microtubule pathology. NAP treatment ameliorates, in part, ADNP-associated dysfunctions. The microtubule, stable tubule-only polypeptide (STOP) knockout mice were shown to provide a reliable model for schizophrenia. Here, STOP-/- as well as STOP+/- showed schizophrenia-like symptoms (hyperactivity) that were ameliorated by chronic treatment with the antipsychotic drug, clozapine. Daily intranasal NAP treatment significantly decreased hyperactivity in the STOP+/- mice and protected visual memory.

The beta-endorphin role in stress-related psychiatric disorders.

Long known for its anti-nociceptive effects, the opioid beta-endorphin is also reported to have rewarding and reinforcing properties and to be involved in stress response. In this manuscript we summarize the present neurobiological and behavioral evidence regarding the role of beta-endorphin in stress-related psychiatric disorders, depression and PTSD. There is existing data that support the importance of beta-endorphin neurotransmission in mediating depression. As for PTSD, however, the data is thus far circumstantial. The studies described herein used diverse techniques, such as biochemical measurements of beta-endorphin in various brain sites and behavioral monitoring, in two animal models of depression and PTSD. We suggest that the pathways for stress-related psychiatric disorders, depression and PTSD, converge to a common pathway in which beta-endorphin is a modulating element of distress. This may occur via its interaction with the mesolimbic monoaminergic system and also by its interesting effects on learning and memory. The possible involvement of beta-endorphin in the process of stress-related psychiatric disorders, depression and PTSD, is discussed.