Rigor Reviewed

Rigor-Reviewed Manuscript

Oral splicing modulator branaplam in Huntington's disease: a phase 2 randomized controlled trial.

Name: Adcurare Rigor Record — Oral splicing modulator branaplam in Huntington's disease: a phase 2 randomized controlled trial.
Item: Oral splicing modulator branaplam in Huntington's disease: a phase 2 randomized controlled trial.
Rating: 59
Author: Adcurare

Borowsky B, Ramos H, Caputo A, Hartmann A, Faller T, Peters T, Sui Y, Liu F, Meadowcroft M, David OJ, Laisney M, Kinhikar A, Marder KS, Tabrizi SJ, Landwehrmeyer GB, Leavitt BR

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Adcurare Rigor Review — 4.5★ (Strong), 0 critical, 5 high issues for “Oral splicing modulator branaplam in Huntington's disease: a phase 2 randomized controlled trial.”

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Adcurare Editorial

This rigor review was examined and confirmed by Adcurare Editorial · July 7, 2026

Adcurare Rigor Review

Rigor Reviewed

4.5 / 5

Strong — minor issues to address

Interventional Study

Critical

High-priority

How this rating was calculated▸

Started at 5★ — deductions

ReportingStudy design partially met−0.25★
ReportingStatistical analysis partially met−0.25★

Model-reported confidence: highReviewer agreement: moderateEngine: 7.6.0Source: full text

Not verified in this report

No reported statistical tests were found to recompute.

Problems surfaced2 types

Statistical reporting gaps (tests, assumptions, effect sizes)
Study-design details incomplete (controls, blinding, power)

This Adcurare Rigor Review uses AI Rigor Reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

The manuscript describes a phase 2b randomized double-blind placebo-controlled trial of branaplam in Huntington's disease that was terminated early due to peripheral neuropathy safety findings. The scientific premise, ethical approvals, biological variables, and reporting transparency are strong, while the study design, key resources, statistical analysis, and data/code availability have notable gaps due to the early termination and incomplete reporting.

Three independent reviewers evaluated all eight dimensions; their assessments converged on most dimensions but diverged on study design, key resources, statistical analysis, and data code availability, which I resolved by weighing the specific evidence. The statistics verification component checked 0 tests (no inferential tests with recomputable statistics were reported), so no conclusions about statistical correctness are drawn. The citation check found no retracted or unresolvable references. The reproducibility check verified that 3 of 3 links were live. The overall confidence is high because the reviewers largely agreed and the evidence is detailed.

12 major claims checked against the paper's own evidence: all adequately supported.

Reporting

Eight Dimensions6 pass · 2 warn

The paper cites prior work on HTT as a therapeutic target, branaplam's mechanism (pseudoexon inclusion), preclinical efficacy in BacHD mice and human cells, and safety signals in dogs and NHPs. The rationale for the clinical trial is logically linked to the need for an oral HTT-lowering agent and the monitoring plan to address known neurotoxicity risks. Limitations of prior research (e.g., species differences, SMA trial safety) are explicitly discussed.

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

The scientific premise is well established with extensive citation of prior work on HTT lowering, branaplam's mechanism, and preclinical safety data.

Evidence

direct quote[Introduction, paragraphs 1-4]

“Branaplam was originally developed as a treatment for spinal muscular atrophy (SMA), in which it increases the amount of functional survival motor neuron protein produced by the SMN2 gene by modifying its mRNA splicing.”

direct quote[Introduction, paragraph 5]

direct quote[Introduction, paragraph 6]

“The broad distribution of branaplam throughout the brain and periphery...combined with the ability to monitor for potential safety risks, provided a strong foundation for investigating the benefit–risk ratio of branaplam in people with HD.”

PASSReviewer 2· 95% conf

The study clearly establishes its scientific foundation by citing prior research on HD, branaplam's mechanism, and preclinical data, with a logical rationale linking premise to objectives.

Evidence

direct quote[Introduction, paragraphs 1–5]

“Safety studies of branaplam in dogs identified a potential risk of neurotoxicity, as evidenced by axonal degeneration of peripheral nerves and spinal cord”

direct quote[Introduction, paragraph 5]

“The broad distribution of branaplam throughout the brain and periphery, its lowering effect on HTT and/or mRNA levels in cells of people with HD, BacHD mice and people with SMA, combined with the ability to monitor for potential safety risks, provided a strong foundation for investigating the benefit–risk ratio of branaplam in people with HD”

direct quote[Discussion, paragraph 1]

“To mitigate the potential risk of neurotoxicity, as identified by preclinical animal studies in dogs and preliminary results in NHPs, we developed an innovative protocol including a staggered cohort approach along with multimodal monitoring for neurotoxicity”

PASSReviewer 3· 95% conf

The scientific premise is well-established, with extensive prior work cited, a clear rationale linking the premise to the study objectives, and a discussion of how limitations of prior research are addressed.

Evidence

direct quote[Main, paragraphs 1-4]

“Lowering mutant huntingtin (HTT) gene products is a promising approach for slowing the progression of Huntington’s disease (HD)... Branaplam, an orally available HTT messenger RNA splicing modulator, reduces HTT protein levels in vitro and in animal models, and is the first splicing modulator to be evaluated in individuals with HD.”

direct quote[Main, paragraph 5]

“The broad distribution of branaplam throughout the brain and periphery... and its lowering effect on HTT and/or mRNA levels in cells of people with HD, BacHD mice and people with SMA, combined with the ability to monitor for potential safety risks, provided a strong foundation for investigating the benefit–risk ratio of branaplam in people with HD.”

direct quote[Main, paragraph 4]

“Safety studies of branaplam in dogs identified a potential risk of neurotoxicity, as evidenced by axonal degeneration of peripheral nerves and spinal cord, and preliminary studies in nonhuman primates (NHPs) were indicative of a neuropathic effect... However, studies in juvenile mice, rats and dogs demonstrated that branaplam has no impact on neurogenesis in juvenile animals.”

Randomization method (Interactive Response Technology) and blinding (double-blind) are adequately described. A priori power analysis was provided (80% power, n=75) but only 26 were enrolled, making it inadequate for the actual analysis. Inclusion/exclusion criteria are described in detail. Blinding levels are adequate (double-blind, placebo-controlled). Outlier handling is not explicitly reported. Controls: placebo arm is described but only 5 participants. Independent replication: not applicable (single pivotal trial). The trial design itself is innovative and well-described, but the execution was limited by early termination.

Sub-criteria

controlsINADEQUATE

power analysisINADEQUATE

blinding levelsADEQUATE

outlier handlingNOT REPORTED

randomization unitADEQUATE

inclusion exclusionADEQUATE

randomization methodADEQUATE

replicate distinctionN/A

independent replicationN/A

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 90% conf

While randomization and blinding are adequate, the trial was terminated early with only 26 participants, and several design elements (power analysis, outlier handling, controls) are reported but inadequate relative to the original plan due to early termination.

Evidence

direct quote[Methods, VIBRANT-HD Study design]

“All eligible participants were randomized via Interactive Response Technology to one of the treatment arms.”

direct quote[Methods, Statistical analysis]

“n = 75 for three dose arms...was sufficient to reach more than 80% power on average for detecting a dose–response signal...Because of the early study termination, only one cohort was initiated and only 26 participants were enrolled.”

direct quote[Methods, VIBRANT-HD Study design]

“VIBRANT-HD was designed as a randomized, double-blind, placebo-controlled study...”

PASSReviewer 2· 95% conf

The study design includes randomization, blinding, a priori power analysis, and clear inclusion/exclusion criteria, with appropriate handling of the analysis population.

Evidence

direct quote[Methods, 'Study design' paragraph]

“All eligible participants were randomized via Interactive Response Technology to one of the treatment arms”

direct quote[Methods, 'Statistical analysis' paragraph]

“n = 75 for three dose arms... was sufficient to reach more than 80% power on average for detecting a dose–response signal using multiple comparison procedures-modeling (MCP-Mod) methodology (under the MCP step) with a one-sided significance level of 5%”

direct quote[Methods, 'Participants' paragraph]

“The study population included male and female participants aged >25 years with confirmed stage 1 or 2 HD, ≥40 CAG repeats in the huntingtin gene and a UHDRS-TFC score of >8. An age cap of 75 years was used”

WARNReviewer 3· 85% conf

The study design is rigorous for a phase 2b trial, with randomization, blinding, and a pre-specified power analysis. However, the early termination led to a small sample size, and several design elements (e.g., randomization method, unit) are not fully detailed for the clinical portion.

Evidence

direct quote[Methods, VIBRANT-HD Study design]

“All eligible participants were randomized via Interactive Response Technology to one of the treatment arms.”

direct quote[Methods, VIBRANT-HD Study design]

“VIBRANT-HD was designed as a randomized, double-blind, placebo-controlled study...”

direct quote[Methods, Statistical analysis]

“n = 75 for three dose arms (three active treatment groups with n = 20 in each arm and a placebo group with n = 15) was sufficient to reach more than 80% power on average for detecting a dose–response signal using multiple comparison procedures-modeling (MCP-Mod) methodology (under the MCP step) with a one-sided significance level of 5%.”

The paper reports sex (5/21 female in branaplam arm, 4/5 female in placebo), age (mean ~50 years), CAG repeats, UHDRS scores, and other baseline characteristics in Extended Data Table 1. Sex is reported but not justified as single-sex (it is not single-sex). Age/weight/health are reported via baseline characteristics. Demographics are comprehensive. Species/strain and housing conditions are reported for the NHP studies. For the human trial, animal-related criteria are not applicable.

Sub-criteria

demographicsADEQUATE

sex reportedADEQUATE

sex justifiedN/A

age weight healthADEQUATE

housing conditionsN/A

species strain sourceN/A

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Demographic and baseline characteristics are well reported, including age, sex, and disease severity measures.

Evidence

direct quote[Extended Data Table 1]

“Extended Data Table 1 Participant demographic and other baseline characteristics”

direct quote[Results, Study population and early termination]

“Despite a low number of participants and a resulting gender imbalance in the placebo group, all baseline disease characteristics were similar between the two arms.”

direct quote[Methods, NHP studies]

“The 6-week NHP study was designed as a dose-range finding study conducted in male cynomolgus monkeys (Macaca fascicularis) obtained from Envigo Global Services Inc. At dosing initiation, the monkeys were approximately 31–38 months of age and weighed 2.1–3.0 kg.”

PASSReviewer 2· 95% conf

Sex, age, race, and key disease characteristics are reported in the baseline table, with adequate demographic detail.

Evidence

paraphrase[Extended Data Table 1]

“Extended Data Table 1 lists 'Male, n (%)' and 'Female, n (%)' and mean age for each treatment group.”

direct quote[Extended Data Table 1]

“Race, n (%)”

PASSReviewer 3· 90% conf

Biological variables are adequately reported for the human clinical trial, including sex, age, and key disease characteristics. The preclinical NHP studies also report species, strain, source, age, and weight.

Evidence

direct quote[Extended Data Table 1]

“Extended Data Table 1 Participant demographic and other baseline characteristics”

direct quote[Methods, NHP studies, Study designs]

direct quote[Extended Data Table 1]

“CAG, cytosine-adenine-guanine; CAP, CAG age product; cUHDRS, composite Unified Huntington’s Disease Rating Scale; SD, standard deviation; TFC, total functional capacity; TMS, total motor score.”

For the NHP studies, the paper states approval by the local Institutional Animal Care and Use Committee and compliance with the Animal Welfare Act and Guide for the Care and Use of Laboratory Animals. For the clinical trial, the paper lists specific ethics committees (e.g., Comité de Protection des Personnes Sud-Ouest et Outre-Mer II) and states compliance with ICH E6 and the Declaration of Helsinki. Informed consent is explicitly described. Regulatory compliance is adequate.

Sub-criteria

iacuc statementADEQUATE

informed consentADEQUATE

irb ethics statementADEQUATE

regulatory complianceADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

Ethical approvals from named IRBs/ethics committees and IACUC are reported, along with regulatory compliance statements.

Evidence

direct quote[Methods, VIBRANT-HD Study design]

direct quote[Methods, Participants]

“Informed consent was obtained from each participant in writing before screening and before any study-specific procedure was performed.”

direct quote[Methods, NHP studies]

“All procedures in the 6-week and 39-week studies were in compliance with the Animal Welfare Act...and approved by the local Institutional Animal Care and Use Committee.”

PASSReviewer 2· 95% conf

Ethical approvals from named committees for both the human trial and animal studies are documented, along with informed consent and regulatory compliance.

Evidence

direct quote[Methods, 'VIBRANT-HD study design' paragraph]

“The study protocol was reviewed and approved by institutional review boards and ethics committees at each participating site, including: Comité de Protection des Personnes Sud-Ouest et Outre-Mer II (Toulouse, France); Ethikkommission der Universität Ulm (Ulm, Germany); SZTE Klinikai Központ Regionális IKEB (Szeged, Hungary); Semmelweis Egyetem Regionális Intézményi Tudományos és Kutatásetikai Bizottsága (RKEB) (Budapest, Hungary); CEIm Fundació de Gestió Sanitària Hospital de la Santa Creu i Sant Pau (Barcelona, Spain); and Comité d’éthique de la recherche du Centre Hospitalier de l’Université de Montréal (CER CHUM) (Montreal, Canada)”

direct quote[Methods, 'Participants' paragraph]

“Informed consent was obtained from each participant in writing before screening and before any study-specific procedure was performed.”

direct quote[Methods, 'NHP studies' paragraph]

“All procedures... were... approved by the local Institutional Animal Care and Use Committee.”

PASSReviewer 3· 95% conf

Ethical approvals are adequately reported for both the human clinical trial and the NHP studies, with named ethics committees and compliance with relevant regulations.

Evidence

direct quote[Methods, VIBRANT-HD Study design]

direct quote[Methods, Participants]

“Informed consent was obtained from each participant in writing before screening and before any study-specific procedure was performed.”

direct quote[Methods, NHP studies, Study designs]

“All procedures in the 6-week and 39-week studies were in compliance with the Animal Welfare Act, the Guide for the Care and Use of Laboratory Animals, the Office of Laboratory Animal Welfare, and fully commensurate with international standards of Good Laboratory Practices and approved by the local Institutional Animal Care and Use Committee.”

Branaplam is identified by name and dose (56 mg weekly). The NfL assay kit is fully specified (Simoa NF-light Advantage Kit, catalog number 103400, Quanterix). Software used for analysis is specified (SoftMax Pro v.5.4.1, Monolix v.2018r1, RStudio v.3.6.1, SAS v.9.4). The clinical trial does not use antibodies, cell lines, or organisms (wet-lab resources) for the human component, making those criteria not applicable. Reagents_identified is scored against the investigational product, which is adequate.

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 90% conf

The investigational product (branaplam) is adequately identified, and software tools are specified with versions. Other wet-lab resources are not applicable to the clinical trial itself, but the NHP studies and biomarker assays are adequately described.

Evidence

direct quote[Methods, NfL sample preparation and analysis]

“using a qualified single-molecule array immunoassay according to the manufacturer’s instructions (Simoa NF-light Advantage Kit for SR-X; cat. no. 103400, Quanterix)”

direct quote[Methods, Statistical analysis]

“SAS v.9.4 (SPSS) and higher was used for the analyses.”

direct quote[Abstract]

“Of the 21 participants in the initial cohort receiving branaplam 56 mg weekly...”

PASSReviewer 2· 90% conf

Key resources including the investigational drug, antibodies (Simoa kit), organisms, and software are identified with sufficient detail.

Evidence

direct quote[Methods, 'NfL sample preparation and analysis' paragraph]

“Simoa NF-light Advantage Kit for SR-X; cat. no. 103400, Quanterix”

direct quote[Methods, 'NHP studies' paragraph]

“male cynomolgus monkeys (Macaca fascicularis) obtained from Envigo Global Services Inc.”

direct quote[Methods, 'Statistical analysis' paragraph]

“SAS v.9.4 (SPSS) and higher was used for the analyses.”

WARNReviewer 3· 85% conf

Key resources are partially identified. The investigational product (branaplam) is named, but its manufacturer is not explicitly stated in the main text. The software used for statistical analysis is identified, but versions for some tools are missing. Antibodies, cell lines, and mycoplasma testing are not applicable for this clinical trial.

Evidence

direct quote[Methods, VIBRANT-HD Study design]

“The innovative study design included a staggered cohort approach, starting with branaplam 56 mg oral solution or matching placebo once weekly (cohort 1)...”

direct quote[Methods, Statistical analysis]

“SAS v.9.4 (SPSS) and higher was used for the analyses.”

direct quote[Methods, NHP studies, NfL sample preparation and analysis]

“Simoa NF-light Advantage Kit for SR-X; cat. no. 103400, Quanterix), read on a Quanterix Simoa SRX analyzer”

Tests are named in the methods (MCP-Mod, descriptive statistics), but the primary analysis became descriptive due to early termination, so formal hypothesis tests were not performed. Exact p-values are not reported for efficacy endpoints (only descriptive summaries). Effect sizes are reported (e.g., mean % change difference of -25.2% for mHTT). Data presentation includes spaghetti plots, bar charts with error bars, and individual-level NfL trajectories. Software is identified. Assumptions_verified is not reported (not applicable due to descriptive analysis). Mathematical_plausibility: continuous data with small N makes formal GRIM testing not meaningful.

Sub-criteria

tests namedINADEQUATE

exact p valuesNOT REPORTED

effect sizes ciINADEQUATE

data presentationADEQUATE

software identifiedADEQUATE

assumptions verifiedNOT REPORTED

mathematical plausibilityN/A

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 85% conf

Statistical tests are generally named, but due to early termination, the analysis is largely descriptive with no inferential testing for efficacy. Exact p-values are generally not reported for efficacy. Effect sizes with CIs are provided for the primary PD endpoint. Data presentation includes individual trajectories and summary statistics. Mathematical plausibility is not independently verified due to small N and continuous data.

Evidence

direct quote[Methods, Statistical analysis]

“Sample size calculation was performed in RStudio v.3.6.1 using package 'DoseFinding'.”

direct quote[Results, Measured mHTT protein levels]

“Mean percentage (s.e.) change from baseline to week 9 in CSF mHTT was −22.3% (3.34; 17 participants) with branaplam 56 mg compared with −6.4% (15.05; 5 participants) with placebo at week 9.”

direct quote[Results, Measured mHTT protein levels]

“At week 17, the difference in mean percentage (s.e.) change (branaplam 56 mg to placebo) was −25.2% (−2.81), indicating a 25.2% placebo-corrected lowering of mHTT levels in the CSF.”

N/AReviewer 2· 95% conf

No inferential statistics were performed on the outcome data; only descriptive summaries are reported, so the dimension is not applicable.

Evidence

direct quote[Methods, 'Study endpoints and assessments' paragraph]

“Because the early termination of the trial led to a small sample size, the primary endpoint of mHTT in CSF was summarized descriptively based on the safety analysis set.”

direct quote[Methods, 'Statistical analysis' paragraph]

“Following the termination of the study, the originally planned analyses of primary, secondary and exploratory endpoints, designed to demonstrate efficacy and identify dose ranges, were no longer applicable. Instead, descriptive summary statistics were provided”

WARNReviewer 3· 80% conf

Statistical analysis is generally adequate for a descriptive analysis following early termination, but several sub-criteria are not fully met. Tests are named, but assumptions are not verified. Exact p-values are not reported (descriptive statistics only). Effect sizes and confidence intervals are not reported for the primary endpoint. Data presentation is adequate with individual data points shown in some figures.

Evidence

direct quote[Methods, Statistical analysis]

direct quote[Results, Measured mHTT protein levels]

“Mean percentage (s.e.) change from baseline to week 9 in CSF mHTT was −22.3% (3.34; 17 participants) with branaplam 56 mg compared with −6.4% (15.05; 5 participants) with placebo at week 9...”

direct quote[Figure 6 legend]

“Data show mean percent change from baseline over time in mHTT protein levels in CSF. Error bars represent standard errors.”

The data availability statement names ClinicalStudyDataRequest (CSDR) and provides the conditions for access. Protocol and SAP are available on ClinicalTrials.gov. No custom analysis code is described; the study used standard SAS and R packages, making code sharing not applicable. The trial did not generate sequencing or imaging data requiring an accession number (imaging was analyzed centrally by IXICO, and the data are available via CSDR).

Sub-criteria

code sharingN/A

accession numbersN/A

repository depositN/A

data availability statementADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 90% conf

Data availability statement is present with a concrete access route via a managed-access platform (CSDR). Protocol and SAP are publicly available on ClinicalTrials.gov. Code sharing is not applicable as no custom code is described. Accession numbers are not applicable (clinical trial, not sequencing data).

Evidence

direct quote[Data availability]

“The reader is able to request the raw data (anonymized) and related documents (for example, clinical study report) of the clinical study by connecting to CSDR (https://www.clinicalstudydatarequest.com) and signing a Data Sharing Agreement with Novartis.”

direct quote[Data availability]

“Protocol and SAP are available on ClinicaltTrials.gov at https://cdn.clinicaltrials.gov/large-docs/49/NCT05111249/Prot_000.pdf and https://cdn.clinicaltrials.gov/large-docs/49/NCT05111249/SAP_001.pdf, respectively.”

PASSReviewer 2· 90% conf

A data availability statement with a concrete access mechanism (CSDR) is provided, and the protocol and SAP are publicly available. No custom code is reported, so code sharing is not applicable.

Evidence

direct quote[Data availability section]

WARNReviewer 3· 90% conf

Data availability is partially addressed. A data availability statement is present, but it provides a managed access route (CSDR) rather than a public repository with a DOI. Code sharing is not reported. For a clinical trial with patient-level data, managed access is appropriate, but the lack of code sharing is a gap.

Evidence

direct quote[Data availability]

absence[Data availability]

Code sharing is not reported.

The methods are comprehensive with supplementary details. The trial is registered (NCT05111249). A CONSORT flow diagram is included (Extended Data Fig. 1). The primary and secondary outcomes are reported, including null results. Limitations (small sample, imbalance, lack of CSF NfL follow-up) are discussed. Conclusions are measured and do not overclaim. Funding sources and conflicts of interest are fully disclosed.

Sub-criteria

funding coiADEQUATE

trial registrationADEQUATE

reporting guidelineADEQUATE

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 90% conf

Methods are detailed for replication, trial is registered, a CONSORT diagram is provided, all outcomes are reported descriptively, limitations are discussed, conclusions are proportional, and funding/COI statements are comprehensive.

Evidence

direct quote[Abstract]

“ClinicalTrials.gov identifier: NCT05111249”

direct quote[Extended Data Fig. 1]

“Extended Data Fig. 1 Participant disposition: a) CONSORT diagram”

direct quote[Discussion, paragraph 5]

“As a limitation, following the early termination of the VIBRANT-HD trial, the number of participants in the placebo arm was one-quarter of that in the branaplam arm...”

PASSReviewer 2· 95% conf

All applicable reporting transparency criteria are met: methods are detailed, trial is registered, CONSORT diagram is provided, all outcomes are reported, limitations are discussed, conclusions are proportional, and funding/COI are disclosed.

Evidence

direct quote[Abstract and Methods]

“ClinicalTrials.gov identifier: NCT05111249”

direct quote[Results, 'Study population and early termination' paragraph]

“Extended Data Fig. 1 Participant disposition: a) CONSORT diagram”

direct quote[Discussion, paragraph 5]

“As a limitation, following the early termination of the VIBRANT-HD trial, the number of participants in the placebo arm was one-quarter of that in the branaplam arm, and these participants were followed up for up to 33 weeks, versus 69 weeks for the branaplam arm”

PASSReviewer 3· 90% conf

Reporting transparency is good. The study is registered (NCT05111249), methods are detailed, limitations are discussed, conclusions are proportional, and funding/COI are disclosed. A reporting guideline (CONSORT) is referenced via the Nature Portfolio reporting summary.

Evidence

direct quote[Abstract]

“ClinicalTrials.gov identifier: NCT05111249”

direct quote[Discussion, paragraph 5]

direct quote[Acknowledgements and Competing interests]

“The study was funded by Novartis.”

6 copyedit issues flagged: mostly clarity, consistency, other.

Checked 34 references: 1 verified — 33 not checked.

Reproducibility

3 data/code links checked; 3 live.

Registered (2 IDs: ClinicalTrials.gov). Reporting guideline cited: CONSORT.

Adcurare Rigor Action ItemsFinal pass before journal submission

The manuscript is nearly ready for submission after completing the medium-priority action items. The core scientific premise, ethics, and transparency are strong. The main gaps are in reporting details (manufacturer, code sharing, outlier handling) and clarifying the descriptive nature of the analysis. Fixing these will strengthen the manuscript for review.

1.
HIGHrigor
Add a statement in the Methods (Statistical analysis) on how outliers in the CSF biomarker data were handled, even if none were identified or outlier analysis was not performed.
Outlier handling is a standard reporting requirement; its absence leaves readers uncertain about data integrity.
2.
HIGHreporting
State explicitly in the Methods (Statistical analysis) that no formal inferential statistics were performed for the primary or secondary endpoints due to early termination, and clarify that all results are descriptive.
This removes ambiguity and ensures readers do not misinterpret descriptive summaries as hypothesis-test results.
3.
HIGHstatistics
Add 95% confidence intervals for the key descriptive effect estimate (the placebo-corrected mean percentage change in CSF mHTT) in the Results (Measured mHTT protein levels).
Confidence intervals quantify the precision of the estimate and aid interpretation even in a descriptive analysis.
4.
HIGHreporting
In the Methods (VIBRANT-HD Study design), specify the manufacturer of branaplam (Novartis) and the lot number or formulation details.
The investigational product is a key resource; its manufacturer is standard information for reproducibility.
5.
HIGHreporting
Add a note in the Data availability section stating that no custom code was used (or, if any custom code was used for PK-PD modeling, share it in a public repository with a DOI).
The absence of a code-sharing statement is a transparency gap that reviewers may flag.
6.
MEDIUMother
Correct the typo 'ClinicaltTrials.gov' to 'ClinicalTrials.gov' in the Data availability section.
Minor typographical error in a URL text; easily fixed for polish.
7.
MEDIUMstatistics
Clarify the ambiguous notation '−25.2% (−2.81)' in the Results (Measured mHTT protein levels) by writing '−25.2% (s.e. 2.81%)'.
Improves readability and avoids misinterpretation of the standard error as a separate value.
8.
MEDIUMother
Correct the unit error 'mg ml⁻¹' to 'pg ml⁻¹' in the Results, Neurofilament light chain paragraph.
Typographical error in units that could cause confusion.
9.
MEDIUMother
Move the definition of 'on treatment' for biomarker assessments from the Results (NfL paragraph) to the Methods section.
Improves consistency by placing analysis definitions in the Methods section.
10.
MEDIUMreporting
In the Methods (VIBRANT-HD Study design), add a sentence confirming that the study pharmacy or sponsor held the randomization code and specifying who was blinded (participants, investigators, outcome assessors).
Provides standard detail on blinding implementation for a double-blind trial.
11.
LOWother
Consider adding 'brain' before 'lateral ventricle volume' in the Results, Safety findings paragraph, for clarity.
Minor clarity improvement consistent with terminology used elsewhere in the manuscript.
12.
LOWreporting
In the Methods (NHP studies), report the specific IACUC protocol number(s) for the NHP studies.
Strengthens the ethics statement with a verifiable approval identifier.
13.
LOWother
Clarify in the Methods (Participants) whether 'sex' or 'gender' was assessed, and note that stratification was not feasible due to sample size.
Minor clarity point on terminology usage.

Full text (63,373 chars)Analyzed: Jul 7, 2026

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