A proof-of-concept study with SOM3355 (bevantolol hydrochloride) for reducing chorea in Huntington's disease.

AIMS: The study's aim is to investigate the efficacy and safety of SOM3355 (bevantolol hydrochloride), a ß1 -adrenoreceptor antagonist with recently identified vesicular monoamine transporter type 2 inhibitory properties, as a repositioned treatment to reduce chorea in Huntington's disease (HD). METHODS: A randomized, placebo-controlled proof-of-concept study was performed in 32 HD patients allocated to 2 arms of 4 sequential 6-week periods each. Patients received placebo and SOM3355 at 100 and 200 mg twice daily in a crossover design. The primary endpoint was improvement by at least 2 points in the total maximal chorea score in any active drug period compared with the placebo period. RESULTS: The primary endpoint was met in 57.1% of the patients. Improvements ≥3, ≥4, ≥5 and ≥6 points vs. placebo treatment were observed in 28.6, 25.0, 17.9 and 10.7% of the patients, respectively. A mixed-model analysis found a significant improvement in the total maximal chorea score of -1.14 (95% confidence interval, -2.11 to -0.16; P = .0224) with 200 mg twice daily SOM3355 treatment compared with placebo treatment. These results were paralleled by Clinical and Patient Global Impression of Change ratings (secondary endpoints). An elevation in plasma prolactin levels by 1.7-1.9-fold was recorded (P < .005), probably reflecting the effect on the dopamine pathway, consistent with vesicular monoamine transporter type 2 inhibition. The most frequent adverse events during SOM3355 administration were mild to moderate. CONCLUSION: Within the limits of this study, the results suggest that SOM3355 reduces chorea in patients with HD and is well-tolerated. Larger studies are necessary to confirm its therapeutic utility as an antichoreic drug. EudraCT number: 2018-000203-16 and ClinicalTrials.gov Identifier: NCT03575676.

A Study of Drug Repurposing to Identify SARS-CoV-2 Main Protease (3CLpro) Inhibitors.

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wreaked havoc all over the world. Although vaccines for the disease have recently become available and started to be administered to the population in various countries, there is still a strong and urgent need for treatments to cure COVID-19. One of the safest and fastest strategies is represented by drug repurposing (DRPx). In this study, thirty compounds with known safety profiles were identified from a chemical library of Phase II-and-up compounds through a combination of SOM Biotech's Artificial Intelligence (AI) technology, SOMAIPRO, and in silico docking calculations with third-party software. The selected compounds were then tested in vitro for inhibitory activity against SARS-CoV-2 main protease (3CLpro or Mpro). Of the thirty compounds, three (cynarine, eravacycline, and prexasertib) displayed strong inhibitory activity against SARS-CoV-2 3CLpro. VeroE6 cells infected with SARS-CoV-2 were used to find the cell protection capability of each candidate. Among the three compounds, only eravacycline showed potential antiviral activities with no significant cytotoxicity. A further study is planned for pre-clinical trials.

Transthyretin stabilization activity of the catechol-O-methyltransferase inhibitor tolcapone (SOM0226) in hereditary ATTR amyloidosis patients and asymptomatic carriers: proof-of-concept study.

Objective: To assess the transthyretin (TTR) stabilization activity of tolcapone (SOM0226) in patients with hereditary ATTR amyloidosis, asymptomatic carriers and healthy volunteers. Methods: A phase IIa proof-of-concept trial included two phases separated by a 6-week washout period. Phase A: single 200 mg dose of tolcapone; phase B: three 100 mg doses taken at 4 h intervals. The primary efficacy variable was TTR stabilization. Results: Seventeen subjects were included (wild type, n = 6; mutation TTR Val30Met, n = 11). TTR stabilization was observed in all participants. Two hours after dosing, 82% of participants in phase A and 93% of those in phase B reached a TTR stabilization value of at least 20%. In phase A, there was an increase of 52% in TTR stabilization vs baseline values 2 h after dosing, which decreased to 22.9% at 8 h. In phase B, there was a significant increase of 38.8% in TTR stabilization 2 h after the first 100 mg dose. This difference was maintained after 10 h and decreased after 24 h. No serious adverse events were observed. Conclusions: The ability of tolcapone for stabilizing TTR supports further development and repositioning of the drug for the treatment of ATTR amyloidosis. EudraCT trial number: 2014-001586-27 ClinicalTrials.gov Identifier: NCT02191826.

Repositioning tolcapone as a potent inhibitor of transthyretin amyloidogenesis and associated cellular toxicity.

Transthyretin (TTR) is a plasma homotetrameric protein implicated in fatal systemic amyloidoses. TTR tetramer dissociation precedes pathological TTR aggregation. Native state stabilizers are promising drugs to treat TTR amyloidoses. Here we repurpose tolcapone, an FDA-approved molecule for Parkinson's disease, as a potent TTR aggregation inhibitor. Tolcapone binds specifically to TTR in human plasma, stabilizes the native tetramer in vivo in mice and humans and inhibits TTR cytotoxicity. Crystal structures of tolcapone bound to wild-type TTR and to the V122I cardiomyopathy-associated variant show that it docks better into the TTR T4 pocket than tafamidis, so far the only drug on the market to treat TTR amyloidoses. These data indicate that tolcapone, already in clinical trials for familial amyloid polyneuropathy, is a strong candidate for therapeutic intervention in these diseases, including those affecting the central nervous system, for which no small-molecule therapy exists.