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Cannabidiol (CBD), the main non‐intoxicating compound in cannabis, has been hypothesized to reduce the adverse effects of Δ9‐tetrahydrocannabinol (THC), the main psychoactive and analgesic component of cannabis. This clinical trial investigated the hypothesis that CBD counteracts the adverse effects of THC and thereby potentially improves the tolerability of cannabis as an analgesic. A randomized, double‐blind, placebo‐controlled, five‐way cross‐over trial was performed in 37 healthy volunteers. On each visit, a double‐placebo, THC 9 mg with placebo CBD, or THC 9 mg with 10, 30, or 450 mg CBD was administered orally. Psychoactive and analgesic effects were quantified using standardized test batteries. Pharmacokinetic sampling was performed. Data were analyzed using mixed‐effects model. Co‐administration of 450 mg CBD did not reduce, but instead significantly increased subjective, psychomotor, cognitive, and autonomous effects of THC (e.g., VAS "Feeling High" by 60.5% (95% CI: 12.7%, 128.5%, P < 0.01)), whereas THC effects with 10 and 30 mg CBD were not significantly different from THC alone. CBD did not significantly enhance THC analgesia at any dose level. Administration of 450 mg CBD significantly increased AUClast of THC (AUClast ratio: 2.18, 95% CI: 1.54, 3.08, P < 0.0001) and 11‐OH‐THC (AUClast ratio: 6.24, 95% CI: 4.27, 9.12, P < 0.0001) compared with THC alone, and 30 mg CBD significantly increased AUClast of 11‐OH‐THC (AUClast ratio: 1.89, 95% CI: 1.30, 2.77, P = 0.0013), and of THC (AUClast ratio: 1.44, 95% CI: 1.01, 2.04, P = 0.0446). Present findings do not support the use of CBD to reduce adverse effects of oral THC or enhance THC analgesia. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is a neuromuscular disease that results in compromised transmission of electrical signals at the neuromuscular junction (NMJ) from motor neurons to skeletal muscle fibers. As a result, patients with MG have reduced skeletal muscle function and present with symptoms of severe muscle weakness and fatigue. ClC-1 is a skeletal muscle specific chloride (Cl−) ion channel that plays important roles in regulating neuromuscular transmission and muscle fiber excitability during intense exercise. Here, we show that partial inhibition of ClC-1 with an orally bioavailable small molecule (NMD670) can restore muscle function in rat models of MG and in patients with MG. In severely affected MG rats, ClC-1 inhibition enhanced neuromuscular transmission, restored muscle function, and improved mobility after both single and prolonged administrations of NMD670. On this basis, NMD670 was progressed through nonclinical safety pharmacology and toxicology studies, leading to approval for testing in clinical studies. After successfully completing phase 1 single ascending dose in healthy volunteers, NMD670 was tested in patients with MG in a randomized, placebo-controlled, single-dose, three-way crossover clinical trial. The clinical trial evaluated safety, pharmacokinetics, and pharmacodynamics of NMD670 in 12 patients with mild MG. NMD670 had a favorable safety profile and led to clinically relevant improvements in the quantitative myasthenia gravis (QMG) total score. This translational study spanning from single muscle fiber recordings to patients provides proof of mechanism for ClC-1 inhibition as a potential therapeutic approach in MG and supports further development of NMD670. Editor's summary: Myasthenia gravis (MG) is caused by an autoimmune response against postsynaptic components of the neuromuscular junction, leading to impaired communication between motor neurons and muscle fibers. Here, Skov et al. show that inhibition of the ClC-1 chloride channel with an orally bioavailable small molecule (NMD670) augmented muscle excitability in response to motor commands and thereby improved muscle function in rat models of MG. Data from a small randomized clinical trial demonstrate that treatment with NMD670 was well tolerated in patients with MG and improved a quantitative disease severity score. These findings support further clinical development of ClC-1 inhibitors for MG. —Daniela Neuhofer [ABSTRACT FROM AUTHOR]

Background: Leucine‐rich repeat kinase 2 (LRRK2) inhibition is a promising therapeutic approach for the treatment of Parkinson's disease (PD). Objective: The aim of this study was to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of the potent, selective, CNS‐penetrant LRRK2 inhibitor BIIB122 (DNL151) in healthy participants and patients with PD. Methods: Two randomized, double‐blind, placebo‐controlled studies were completed. The phase 1 study (DNLI‐C‐0001) evaluated single and multiple doses of BIIB122 for up to 28 days in healthy participants. The phase 1b study (DNLI‐C‐0003) evaluated BIIB122 for 28 days in patients with mild to moderate PD. The primary objectives were to investigate the safety, tolerability, and plasma pharmacokinetics of BIIB122. Pharmacodynamic outcomes included peripheral and central target inhibition and lysosomal pathway engagement biomarkers. Results: A total of 186/184 healthy participants (146/145 BIIB122, 40/39 placebo) and 36/36 patients (26/26 BIIB122, 10/10 placebo) were randomized/treated in the phase 1 and phase 1b studies, respectively. In both studies, BIIB122 was generally well tolerated; no serious adverse events were reported, and the majority of treatment‐emergent adverse events were mild. BIIB122 cerebrospinal fluid/unbound plasma concentration ratio was ~1 (range, 0.7–1.8). Dose‐dependent median reductions from baseline were observed in whole‐blood phosphorylated serine 935 LRRK2 (≤98%), peripheral blood mononuclear cell phosphorylated threonine 73 pRab10 (≤93%), cerebrospinal fluid total LRRK2 (≤50%), and urine bis (monoacylglycerol) phosphate (≤74%). Conclusions: At generally safe and well‐tolerated doses, BIIB122 achieved substantial peripheral LRRK2 kinase inhibition and modulation of lysosomal pathways downstream of LRRK2, with evidence of CNS distribution and target inhibition. These studies support continued investigation of LRRK2 inhibition with BIIB122 for the treatment of PD. © 2023 Denali Therapeutics Inc and The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Selective voltage‐gated sodium channel blockers are of growing interest as treatment for pain. For drug development of such compounds, it would be critical to have a biomarker that can be used for proof‐of‐mechanism. We aimed to evaluate whether drug‐induced changes in sodium conductance can be detected in the peripheral nerve excitability profile in 18 healthy subjects. In a randomized, double‐blind, 3‐way crossover study, effects of single oral doses of 333 mg mexiletine and 300 mg lacosamide were compared with placebo. On each study visit, motor and sensory nerve excitability measurements of the median nerve were performed (predose; and 3 and 6 hours postdose) using Qtrac. Treatment effects were calculated using an analysis of covariance (ANCOVA) with baseline as covariate. Mexiletine and lacosamide had significant effects on multiple motor and sensory nerve excitability variables. Depolarizing threshold electrotonus (TEd40 (40–60 ms)) decreased by mexiletine (estimated difference (ED) −1.37% (95% confidence interval (CI): −2.20, −0.547; P = 0.002) and lacosamide (ED −1.27%, 95% CI: −2.10, −0.443; P = 0.004) in motor nerves. Moreover, mexiletine and lacosamide decreased superexcitability (less negative) in motor nerves (ED 1.74%, 95% CI: 0.615, 2.87; P = 0.004, and ED 1.47%, 95% CI: 0.341, 2.60; P = 0.013, respectively). Strength‐duration time constant decreased after lacosamide in motor‐ (ED −0.0342 ms, 95% CI: −0.0571, −0.0112; P = 0.005) and sensory nerves (ED −0.0778 ms, 95% CI: −0.116, −0.0399; P < 0.001). Mexiletine and lacosamide significantly decrease excitability of motor and sensory nerves, in line with their suggested mechanism of action. Results of this study indicate that nerve excitability threshold tracking can be an effective pharmacodynamic biomarker. The method could be a valuable tool in clinical drug development. [ABSTRACT FROM AUTHOR]

Receptor‐interacting serine/threonine‐protein kinase 1 (RIPK1) regulates inflammation, cytokine release, and necroptotic cell death and is implicated in pathogenic cellular pathways in amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and multiple sclerosis. Inhibition of RIPK1 activity protects against inflammation and cell death in multiple animal models. DNL104 is a selective, brain‐penetrant inhibitor of RIPK1 phosphorylation in clinical development for AD and ALS. DNL104 was tested in 68 healthy volunteers to investigate safety and tolerability, pharmacokinetic profile in plasma and cerebrospinal fluid, and pharmacodynamic effects of RIPK1 inhibition in peripheral blood mononuclear cells in a first‐in‐human, placebo‐controlled, double‐blind, randomized single‐ascending dose (SAD) and multiple‐ascending dose (MAD) study. DNL104 was well‐tolerated in the SAD group and during the dosing period of the MAD group. However, postdose liver toxicity in 37.5% of subjects was observed in the MAD, and assessed to be drug related. We demonstrate that DNL104 leads to RIP1 kinase inhibition, and this is not associated with central nervous system (CNS) toxicities, supporting future development of CNS penetrant RIPK1 inhibitors. [ABSTRACT FROM AUTHOR]

Recombinant human erythropoietin (rHuEPO) is used as doping a substance. Anti‐doping efforts include urine and blood testing and monitoring the athlete biological passport (ABP). As data on the performance of these methods are incomplete, this study aimed to evaluate the performance of two common urine assays and the ABP. In a randomized, double‐blinded, placebo‐controlled trial, 48 trained cyclists received a mean dose of 6000 IU rHuEPO (epoetin β) or placebo by weekly injection for eight weeks. Seven timed urine and blood samples were collected per subject. Urine samples were analyzed by sarcosyl‐PAGE and isoelectric focusing methods in the accredited DoCoLab in Ghent. A selection of samples, including any with false presumptive findings, underwent a second sarcosyl‐PAGE confirmation analysis. Hematological parameters were used to construct a module similar to the ABP and analyzed by two evaluators from an Athlete Passport Management Unit. Sensitivity of the sarcosyl‐PAGE and isoelectric focusing assays for the detection of erythropoietin abuse were 63.8% and 58.6%, respectively, with a false presumptive finding rate of 4.3% and 6%. None of the false presumptive findings tested positive in the confirmation analysis. Sensitivity was highest between 2 and 6 days after dosing, and dropped rapidly outside this window. Sensitivity of the ABP was 91.3%. Specificity of the urine assays was high; however, the detection window of rHuEPO was narrow, leading to questionable sensitivity. The ABP, integrating longitudinal data, is more sensitive, but there are still subjects that evade detection. Combining these methods might improve performance, but will not resolve all observed shortcomings. [ABSTRACT FROM AUTHOR]

Increased excitability of motor neurons in patients with amyotrophic lateral sclerosis (ALS) may be a relevant factor leading to motor neuron damage. This randomized, double‐blind, three‐way crossover, placebo‐controlled study evaluated peripheral motor nerve excitability testing as a biomarker of hyperexcitability and assessed the effects of riluzole and retigabine in 18 patients with ALS. We performed excitability testing at baseline, and twice after participants had received a single dose of either 100 mg riluzole, 300 mg retigabine, or placebo. Between‐ and within‐day repeatability was at least acceptable for 14 out of 18 recorded excitability variables. No effects of riluzole on excitability testing were observed, but retigabine significantly decreased strength‐duration time‐constant (9.2%) and refractoriness at 2 ms (10.2) compared to placebo. Excitability testing was shown to be a reliable biomarker in patients with ALS, and the acute reversal of previously abnormal variables by retigabine justifies long‐term studies evaluating the impact on disease progression and survival. [ABSTRACT FROM AUTHOR]