Neurology · Medical Literature
Efficacy and safety of DMB-I (latrepirdine) therapy in mild to moderate dementia in Alzheimer's disease: results of a multicenter, double-blind, randomized, placebo-controlled, clinical trial in three parallel groups.
Abstract
Alzheimer’s disease (AD) is one of leading dementia causes, affecting over 50 million people worldwide. A multicenter, double-blind, randomized, placebo-controlled clinical trial in three parallel groups was conducted to evaluate efficacy and safety of Latrepirdine polymorph DMB-I in 26-week treatment of dementia in patients with AD. 135 patients of both sexes aged 60 to 90 years were randomized into three groups: DMB-I + placebo, 30 mg/day; DMB-I, 60 mg/day and Placebo. Treatment efficacy was assessed using Alzheimer’s disease Assessment Scale cognitive subscale (ADAS-cog), Mini-Mental State Examination (MMSE-2), quality of life questionnaire (QOL-AD), Clinical Global Impression scale (CGI) and Instrumental Activities of Daily Living score (IADL). Clinical parameters and adverse events (AEs) also assessed. The efficacy of DMB-I at a dose of 60 mg/day was demonstrated by assessing the primary efficacy criterion, namely, a significant change in the ADAS-cog score after 26 weeks of treatment compared with baseline. Severity of cognitive impairment dynamics on ADAS-cog, CGI and LADL scales was significantly improved in groups receiving DMB-I at both doses, compared with placebo. AEs overall incidence was similar between DMB-I and Placebo groups. 26-week therapy with DMB-I at both doses demonstrated efficacy and favorable safety profile. 60 mg/day dose was selected as optimal dose for further studies. Study retrospectively registered on Clinicaltrials.gov on February 27, 2024, NCT06292351.
Clinical relevance
Does DMB-I (latrepirdine polymorph), administered at 30 mg/day or 60 mg/day for 26 weeks, improve cognitive and functional outcomes compared with placebo in patients with mild-to-moderate Alzheimer's disease dementia? __SNAPSHOT__ {"studyDesign":"Multicenter, double-blind, randomized, placebo-controlled clinical trial with three parallel groups","setting":"Seven clinical test facilities in Russia (multicenter); drug manufactured by Organica JSC, Russia","sampleSize":"n=135 (DMB-I 30 mg/day: ~45; DMB-I 60 mg/day: ~45; placebo: ~45 — exact per-arm allocation not reported in abstract)","population":"Patients of both sexes aged 60–90 years with mild-to-moderate dementia due to Alzheimer's disease; exclusion criteria included other causes of dementia (e.g., Parkinson's disease, stroke, uncontrolled epilepsy), active oncological disease, CNS/cardiovascular/endocrine/GI disorders, concurrent use of prohibited agents (tricyclic antidepressants, antipsychotics, nootropics, anti-dementia drugs, Cerebrolysin, Ginkgo biloba), substance use disorders, systemic infections, or participation in another trial within 6 months","intervention":"DMB-I (a specific crystalline polymorph of latrepirdine) oral tablets at 30 mg/day (co-administered with placebo tablets) or 60 mg/day for 26 weeks","comparator":"Placebo tablets (identical in appearance, manufactured by Organica JSC, Russia) for 26 weeks","primaryOutcome":"Change from baseline in Alzheimer's Disease Assessment Scale – Cognitive Subscale (ADAS-cog) score at 26 weeks","followUp":"26 weeks","fundingSource":"Not reported in abstract; the sponsor entity BIGESPAS Ltd (a small UK-registered biotech) has been identified in related reporting as self-funded with initial investor support; no government or major industry sponsorship disclosed"}
Key findings
Based on the available abstract, DMB-I at 60 mg/day demonstrated a statistically significant change in ADAS-cog score from baseline at 26 weeks compared with placebo — the primary efficacy endpoint. Statistically significant improvements were also reported on secondary outcome measures of cognitive severity (ADAS-cog), global clinical status (CGI), and instrumental activities of daily living (IADL) in the groups receiving DMB-I compared with placebo. The abstract does not report the magnitude of mean ADAS-cog change, between-group difference, 95% confidence intervals, exact p-values, or effect sizes for any outcome — these values are not reported. Whether the 30 mg/day arm met the primary endpoint is not clearly stated in the abstract; secondary scale improvements appear to encompass both active-dose groups. No serious or life-threatening adverse events were reported per related secondary reporting, and DMB-I appeared generally well tolerated, consistent with the known safety profile of latrepirdine; however, specific adverse event rates, types, and statistical comparisons are not reported in the abstract. NNT and NNH cannot be calculated from available data.
Practice implications
This trial establishes a statistically significant signal for DMB-I 60 mg/day on the primary ADAS-cog endpoint at 26 weeks in a Russian multicenter population of patients with mild-to-moderate AD. However, several critical interpretive limitations apply. First, only the abstract was available for this review; full numerical results, effect sizes, confidence intervals, and adverse event frequencies were not accessible, preventing robust appraisal of clinical importance. Second, the sample size of 135 across three arms (approximately 45 per group) is small, increasing the risk of type I error and limiting precision of estimates. Third, latrepirdine has a complex and inconsistent clinical history: an early Russian phase II trial showed strong positive results, yet multiple subsequent phase III trials — including the multinational CONNECTION study by Pfizer/Medivation — failed to replicate benefit on ADAS-cog or global function in non-Russian populations. The Cochrane meta-analysis of three pivotal phase III trials found no significant effect on cognition or function. Fourth, DMB-I is specifically a novel crystalline polymorph of latrepirdine; while the polymorph distinction is the scientific rationale for renewed investigation, no head-to-head pharmacokinetic or clinical data comparing DMB-I to prior latrepirdine formulations are reported here. Fifth, the trial was conducted exclusively in Russia, limiting generalizability to Western or ethnically diverse populations, where prior trials of the same molecule failed. Sixth, concurrent use of approved AD pharmacotherapies (e.g., cholinesterase inhibitors, memantine) is not discussed; whether patients were on background AD therapy is not reported. Seventh, amyloid or tau biomarker confirmation of AD diagnosis is not mentioned, raising uncertainty about diagnostic homogeneity. Eighth, the trial appears to have been sponsored by a small self-funded biotech with a commercial interest in the molecule, introducing potential for sponsorship bias. The findings are hypothesis-generating and warrant independent replication in larger, internationally diverse, biomarker-confirmed populations before any practice consideration. __LIMITATIONS__ Only the abstract was available; full statistical results (mean differences, confidence intervals, p-values, effect sizes, adverse event rates) could not be verified.,Small sample size (n=135 total, approximately n=45 per arm) substantially limits statistical power and precision, and increases the risk of a false-positive primary endpoint finding.,Single-country trial (Russia only) with marked generalizability concerns given that prior latrepirdine phase III trials conducted in multinational settings consistently failed to demonstrate efficacy on the same ADAS-cog endpoint.,Potential sponsorship and investigator bias: trial conducted by a small self-funded biotech (BIGESPAS Ltd) with direct commercial interest in DMB-I; independent academic or government oversight not reported.,Absence of amyloid/tau biomarker confirmation of AD diagnosis introduces diagnostic heterogeneity and limits comparability with contemporary trial standards.,Concurrent use of approved standard-of-care AD agents (cholinesterase inhibitors, memantine) is not described, making it unclear whether this was a monotherapy or add-on trial.,The 30 mg/day arm's performance on the primary endpoint is ambiguous in the abstract; differential dose-response interpretation requires full data.,26-week follow-up is short for a progressive neurodegenerative disease; durability of any benefit beyond this period is unknown.,The clinical meaningfulness of the observed ADAS-cog change cannot be assessed without the magnitude of the effect; statistically significant changes on ADAS-cog in small trials have frequently not translated to clinical benefit.,Prior phase III failures with the same molecule in larger, multinational trials represent a substantial historical signal of non-replicability that this single small trial cannot overcome.,No blinding adequacy assessment or allocation concealment detail is reported in the abstract. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This small (n=135), single-country, 26-week RCT reports a statistically significant ADAS-cog improvement with DMB-I 60 mg/day versus placebo in mild-to-moderate AD; however, effect sizes are not reported in the abstract and the result cannot be assessed for clinical meaningfulness. Given the prior consistent failure of latrepirdine in larger, multinational phase III trials, the monocentric geographic setting, the small sample, and potential sponsorship bias, these findings are preliminary and hypothesis-generating only. Independent replication in larger, biomarker-confirmed, internationally diverse populations is required before this agent can be considered for clinical practice.