PONE-D-24-36443A DOUBLE-BLIND, PLACEBO-CONTROLLED, RANDOMIZED, MULTI-CENTRE, PHASE III STUDY OF MLC901 (NEUROAID IITM) FOR THE TREATMENT OF COGNITIVE IMPAIRMENT AFTER MILD TRAUMATIC BRAIN INJURYPLOS ONE

Dear Dr. Feigin,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Thank you for your patience with this mamuscript.  I sent it to over 20 potential reviewers, but only one has responded with a critique as well as the statistical referee.  I read through the paper and agree with the assessment of the reviewer with a decision for revision along the lines you will see below.

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Steven E. Wolf, MD

Academic Editor

PLOS ONE

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Additional Editor Comments (if provided):

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: As the statistical reviewer I will focus on methods and reporting. This is generally and well reported study. The main model is appropriate.

Major

1) the power calculation should be presented before the "study participants" section.

2) in the methods section clarify which time points were assessed - was there a primary endpoint? 3 months, 6months? or 9 months. Also how was that factored into the mixed effects model? a separate model for each endpoint, controlled for baseline (arguably the clearest way to analyse and present results from). Alternatively you can have a repeated measures design, which is not what you have (or did not describe as you should have) which may give an "overall" effect across all endpoints.

3) I couldn't replicate the power calculations and i followed the reference the authors provide but i could not tally what was said there to what the authors say (in terms of the SD for example). Nevertheless, the power calculations are correct (on the assumptions provided) but they tend to ignore the potential intraclass correlation coefficient since across many centres. so the authors need to discuss this as a potential problem when it comes to power and also confirm in their response where the information on the assumptions was in the cited paper.

Minor

1) multivariable not multivariate (implies multiple outcomes).

2) methods section "tests of difference" is not a clear enough statement. State the exact tests used for each variable type.

3) the authors say "Model selection was undertaken with each outcome using standard selection heuristics. Covariates were selected based on improving the overall efficiency of the model. Regardless, baseline value of the outcome variable, age, gender, time since injury (1-3 months/4-12 months) and study center were included as covariates in the mixed effects model". The authors need to clarify the model building more clearly in terms of the covariate selection process and explain better how they arrived at the final model.

Reviewer #2: Thank you for the opportunity to review this manuscript. Overall, the study is well-designed and addresses an important clinical question regarding the efficacy and safety of MLC901 (NeuroAiD II) for treating cognitive impairment following mild traumatic brain injury (TBI).

Strengths:

The randomized, double-blind, placebo-controlled, multi-center design is a significant strength and adds considerable value to the research. This approach represents the gold standard for clinical trials, ensuring high internal validity. The use of stratified permuted block randomization and intention-to-treat analysis further enhances the reliability of the results.

The study’s comprehensive evaluation, which includes both primary and secondary outcomes—cognitive functioning, post-concussion symptoms (RPQ), quality of life (QOLIBRI), and the Hospital Anxiety and Depression Scale (HADS)—provides a thorough assessment of the intervention’s effects. Additionally, the detailed reporting of adverse events contributes to the evaluation of the treatment's safety profile.

Achieving a 98% retention rate at the 9-month follow-up is commendable for a study of this length and reinforces the credibility of the data.

Although the primary outcome did not reach statistical significance, the clinically and statistically significant improvements observed in secondary measures—such as post-concussion symptoms, quality of life, anxiety, and depression—are noteworthy and provide valuable insights.

Areas for Improvement:

The lack of significant findings for the primary outcome (complex attention) may raise some concerns. Strengthening the discussion by exploring potential reasons why the intervention did not impact primary cognitive outcomes would be beneficial. It might also help to consider methodological challenges, such as issues with implementing the CNS Vital Signs tool in the Russian context.

Since the CNS Vital Signs tool may not have been fully adapted for use in Russia, this could have influenced the results. It would be helpful to address how cultural and linguistic factors were considered and how they might be mitigated in future research.

The study's population is limited to Russian participants, which may restrict its generalizability. Future studies could benefit from including a more diverse sample to broaden the applicability of the findings.

The data availability statement mentions that some restrictions will apply. For a journal like PLOS ONE, a more open data-sharing policy is typically encouraged. If full data sharing is not possible, a clearer explanation of the restrictions would be beneficial.

The interpretation of the results, particularly the significant improvements in secondary outcomes, could be expanded to provide greater insight into the clinical relevance of MLC901. Even if its cognitive benefits were not demonstrated, the improvement in quality of life and other outcomes is important.

The manuscript could also benefit from some reorganization to enhance clarity, particularly in the results and discussion sections. A more concise presentation of tables and figure legends would help readers better understand the data.

While the discussion covers relevant background information, it would be strengthened by a more thorough comparison with existing literature, particularly other studies on MLC901 and treatments for cognitive impairments following TBI.

Lastly, expanding the discussion of limitations and offering more concrete suggestions for future research would enhance the paper. For example, recommendations for adapting cognitive testing tools to different cultural contexts and exploring the long-term effects of MLC901 on non-cognitive outcomes would be valuable additions.

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Reviewer #1: No

Reviewer #2: No

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A DOUBLE-BLIND, PLACEBO-CONTROLLED, RANDOMIZED, MULTI-CENTRE, PHASE III STUDY OF MLC901 (NEUROAID IITM) FOR THE TREATMENT OF COGNITIVE IMPAIRMENT AFTER MILD TRAUMATIC BRAIN INJURY

PONE-D-24-36443R1

Dear Dr. Feigin,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Steven E. Wolf, MD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: (No Response)

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I am satisfied with the authors' responses and the resulting changes to the manuscript. Nothing else to add.

Reviewer #2: The authors have satisfactorily addressed all of my prior concerns and clarified all points raised in my review.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: No

Reviewer #2: No

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