Kisspeptin as a Precision Biomarker in Personalized Pharmacy: Implications for Individualized Monitoring of Early Pregnancy Viability

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses the interesting topic of the potential role of kisspeptin as a biomarker of early pregnancy viability and its implications for precision medicine. The authors state that they have conducted a systematic review in accordance with PRISMA 2020.

However, despite its correct formal structure (PRISMA, summary tables, risk of bias assessment), the article has significant methodological and conceptual issues that limit its scientific value – particularly in the context of the journal Pharmacy, which focuses on pharmaceutical practice, pharmacotherapy, and pharmaceutical care.

The most important concern is the discrepancy between the data presented and the conclusions regarding ‘personalised pharmacy practice’.

1. Over-extension of conclusions to ‘personalised pharmacy’
The authors repeatedly suggest that kisspeptin has ‘direct relevance to personalised pharmacy practice’ (pp. 1–2). However:
- None of the analysed studies concern pharmaceutical interventions.
- There are no data on the impact of kisspeptin measurement on therapeutic decisions.
- There are no implementation models in pharmacy practice.
- There are no pharmacoeconomic analyses.
- There are no clinical algorithms integrating the biomarker with pharmaceutical care.

In its current form, the article is a review of obstetric biomarkers rather than a clinical pharmacy article. Extending the interpretation to ‘individualised pharmaceutical care’ is conceptually unjustified.

2. Limited number of studies and lack of meta-analysis
The review included 12 studies, of which:
- Only a few concerned serum measurements in clinical trials.
- Some were experimental or immunohistochemical studies.
- No meta-analysis was performed despite the availability of quantitative data (e.g. OR, AUC).

The authors cite heterogeneity as the reason for not conducting a meta-analysis; however:
- No formal assessment of heterogeneity (I²) was performed.
- No sensitivity analysis was presented.
- The lack of quantitative synthesis limits the strength of the conclusions.

As a result, conclusions about ‘strong discriminatory performance’ are based mainly on individual studies.

3. Risk of overinterpretation of results
In the discussion (pp. 7–9), the authors make strong statements such as:
- “kisspeptin may serve as a more sensitive early indicator of placental dysfunction”,
- “holds direct relevance for individualised monitoring strategies”,
- “robust inverse association with pregnancy outcome”.

However:
- All studies are observational.
- There are no interventional studies.
- There is no validation in multicentre populations.
- There is no standardisation of laboratory tests.

In this context, it is premature to describe the biomarker as a ‘precision biomarker’.

4. Lack of critical assessment of study quality
The authors state that the risk of bias was ‘low to moderate’ (p. 4), but:
- No Newcastle–Ottawa Scale scoring table is presented.
- No detailed breakdown of QUADAS-2 scores is provided.
- No qualitative analysis of the impact of bias risk on the strength of conclusions is included.

The quality assessment is declarative rather than analytical.

5. Problem of generalisation
Most studies:
- Involve small groups.
- Differ significantly in gestational age.
- Use different isoforms of kisspeptin (e.g. kisspeptin-54).
- Use different ELISA methods.

The authors note the need for standardisation, yet the conclusions are still formulated as relatively strong.

6. Mechanistic speculation
Sections 4.2–4.4 contain an extensive mechanistic narrative concerning:
- Regulation of trophoblast invasion,
- Dose-response relationships,
- Comparisons with pre-eclampsia.

Although biologically interesting, these sections go beyond the scope of a systematic clinical review and are speculative.

7. Value for pharmaceutical practice
The key question for the journal Pharmacy is: How would a pharmacist use this biomarker? The manuscript does not address this question. The following are not presented:
- Clinical scenarios,
- Integration with pharmacological therapy,
- Implications for dosing,
- Impact on pharmacovigilance,
- The role of the pharmacist in interpreting results.

In its current form, the article would be more appropriate for a journal on obstetrics, endocrinology, or biomarkers than for Pharmacy.

There is no clear indication of the primary endpoint of the review. No assessment of publication bias is provided. Table 4 (‘Evidence synthesis’) is narrative and not based on formal analysis.

Recommendation
Major revision

For the article to be considered for publication in Pharmacy, it is necessary to:
- Clearly limit claims regarding ‘personalised pharmacy’.
- Transform the article into a reliable review of the biomarker, without excessive pharmaceutical implications.
- Expand the risk of bias section with a complete tabular assessment.
- Significantly reduce mechanistic speculation.
- Clearly demonstrate how the biomarker would be used in pharmaceutical practice.
Without these changes, the article does not fit the journal's profile.

Author Response

Reviewer 1

 

We sincerely thank the reviewer for the detailed and insightful evaluation of our manuscript. We appreciate the constructive comments, which have helped us significantly improve the methodological clarity, interpretative balance, and clinical relevance of our work. All major concerns have been carefully addressed as outlined below.

1. Over-extension to personalized pharmacy

Comment: The conclusions overextend the relevance of kisspeptin to personalized pharmacy practice.

Response: We thank the reviewer for this important comment. We agree that the relationship between kisspeptin and personalized pharmacy should be more clearly defined. At the same time, we respectfully maintain that the personalized pharmacy perspective is appropriate for the scope of the journal, as precision biomarkers may contribute not only to therapeutic decisions but also to individualized monitoring, laboratory interpretation, patient counselling, and interdisciplinary clinical support.

To address this concern, we have revised the manuscript to avoid any implication of immediate clinical implementation. The text now clearly presents kisspeptin as a candidate biomarker with potential future relevance to personalized pharmacy, rather than as an established tool in routine pharmaceutical practice.

Changes made:

• The Introduction and Discussion were revised to better define the scope of “personalized pharmacy”.
• Statements implying direct implementation were moderated.
• A dedicated paragraph was added describing the potential role of pharmacists in biomarker-informed monitoring and patient-specific care.

2. Lack of meta-analysis

• Comment: No meta-analysis was performed despite availability of quantitative data.
• Response: We appreciate this comment. A formal meta-analysis was not performed because of marked heterogeneity across the included studies in terms of study design, gestational-age windows, biological material (serum/plasma vs tissue), kisspeptin isoforms, assay platforms, and outcome reporting (including OR and AUC). Under these conditions, quantitative pooling was considered methodologically inappropriate and potentially misleading.
• To clarify this, we have added an explicit justification for qualitative synthesis in the Methods section and expanded the Limitations section accordingly.

3. Overinterpretation of results

Comment: Strong conclusions are not justified by observational data.

Response: We agree and have revised the manuscript to adopt more cautious language throughout. Statements suggesting strong predictive performance or direct clinical applicability have been replaced with more balanced formulations such as “suggestive”, “potential”, and “promising candidate biomarker”. The Conclusion has been rewritten to clearly state that kisspeptin is not yet validated for routine clinical implementation.

4. Risk of bias assessment

Comment: Risk of bias assessment is insufficiently detailed.

Response: We thank the reviewer for this comment. The Risk of Bias section has been expanded to provide a more analytical description of the assessment process. We now explicitly describe the use of the Newcastle–Ottawa Scale and QUADAS-2 domains and discuss key limitations affecting the included studies, including sample size, heterogeneity, and assay variability.

5. Generalisation

Response: We agree and have strengthened the Limitations section to explicitly address limited sample sizes, variability in gestational age, differences in kisspeptin isoforms, and lack of assay standardization. These factors are now clearly presented as constraints on generalizability.

 

6. Mechanistic speculation

Response: The mechanistic discussion has been shortened and revised. We retained a concise biological context but clearly distinguished it from clinical evidence derived from the included studies.

7. Relevance to pharmacy

Response: We have revised the manuscript to more clearly define the pharmaceutical relevance of the review. A new paragraph has been added to explain that the role of pharmacists in this context is currently translational and may include biomarker-informed monitoring, patient counselling, and interdisciplinary care coordination, rather than direct therapeutic decision-making at this stage.

 

Reviewer 2 Report

Comments and Suggestions for Authors

It is well known that precision medicine can efficiently improve early, individualized risk stratification using bio-logically relevant biomarkers. The authors provide a review to probe evidence on maternal serum kisspeptin levels and placental KISS1/KISS1R expression in early pregnancy loss, and to assess its role so as to reach the precision biomarker in personalized pharmacy practice. They list valuable information and summarize data through systematic search of Pub-Med, Scopus, Web of Science, and Google Scholar (up to 2025). At last, they think that Kisspeptin appears to be a promising precision biomarker for monitoring early pregnancy viability and supporting individualized pharmaceutical care. Overall, their work is well organized. Recommending that their work can be accepted after minor revision.

1. In their method section, they obtained data through searching on websites, they should simply clarify how they justify efficiency and reliability of those data.
2. In their figure 1, the authors had better separate this figure three modules and describe the relationships between these modules in the caption of this figure.
3. On a review, their references are too few, suggesting that the authors should enrich their references so as to better evaluate reliability of their review.
4. Although the authors list four tables, they do not perform detailed discussion and explanation on the contents of those tables. Suggesting that the authors should address this issue.

Author Response

We thank the reviewer for the positive evaluation of our manuscript and for the helpful suggestions.

Key responses

1. Search reliability: The Methods section has been revised to clarify database selection, use of predefined criteria, and manual reference screening.
2. Figure 1: The figure caption has been revised to clearly describe identification, screening, and inclusion stages.
3. References: Additional recent and relevant references have been included.
4. Tables: The Results and Discussion sections now provide more detailed interpretation of Tables 1–4.

 

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript shows results published in 12 chosen papers, only 2 of them show the serum concentration of kisspeptin, it is too small data for discussion. Recent review publication https://doi.org/10.22074/ijfs.2017.4957, presents more data what could help with discussion. Taking into account that the methodology of kisspeptin measurements is not perfect, it is difficult to compare the results and making conclusions might be dangerous.

The methodology of search needs better terms; how you explain the fact of exclusion of papers about kisspeptin in non-human females (it should be clearly stated that you are looking ONLY for human).

1. The descriptions of tables must be detailed
2. The control level of kisspeptin must be included in the table (non-pregnant/physiological pregnancy) for justificatin of "decreased level"
3. The comparison of kisspeptin in the serum with changes in the expression of the receptor in the tissues should be justified. Often, decrease/increase of the receptor expression is not connected with the changes with the serum/plasma concentration.
4. One of the references shows the concentration in nmol/l, the second  in ng/ml but as AUC-it should be calculated into the same units for real comparisons
5. Conclusion needs clear statement-is the kisspeptin a right parameter or not?

In summary: the manuscript needs more details, more updated references, some references in the discussion.

Author Response

We thank the reviewer for the detailed and constructive comments, which helped improve the methodological clarity and interpretative rigor of the manuscript.

 

1. Limited serum data

Response: We agree that the number of serum-based studies is limited. This has now been explicitly acknowledged in both the Results and the Limitations sections.

 

2. Human-only clarification

Response: The Methods section has been revised to clarify that the review includes only human studies. We now explicitly state that both clinical biomarker studies and human tissue-based studies were included, while non-human and in vitro studies were excluded.

 

3. Tables description

Response: Table descriptions have been expanded and more detailed narrative interpretation has been added in the Results section.

4. Control levels

Response: Table 2 has been revised to include clearer information on control groups and comparator values, improving transparency of the “decreased level” interpretation.

 

5. Serum vs tissue comparison

Response: A new paragraph has been added in the Discussion to clarify that circulating kisspeptin levels and tissue expression represent related but not directly interchangeable biological domains.

6. Units inconsistency

=Response: Units are now clearly reported as in the original studies, and a table footnote explains limitations in cross-study comparability.

7. Conclusion clarity

Response: The Conclusion has been revised to clearly state that kisspeptin is a promising but not yet validated biomarker.

 

Reviewer 4 Report

Comments and Suggestions for Authors

I have carefully reviewed the submitted manuscript entitled “Kisspeptin as a Precision Biomarker in Personalized Pharmacy: Implications for Individualized Monitoring of Early Pregnancy Viability” by Paunova et al. The manuscript addresses a highly timely and promising topic – kisspeptin as a biomarker of placental function in early pregnancy. The subject is fully aligned with the current paradigm of precision medicine and fits perfectly into the ongoing discussion on novel, non-invasive markers of miscarriage risk. The greatest added value of this review lies in the integration of circulating (serum/plasma) data with immunohistochemical (IHC) findings for KISS1/KISS1R expression in placental and choriodecidual tissues. This represents a significant advance over the majority of existing systematic reviews and meta-analyses, which have focused exclusively on circulating levels.

The manuscript is well structured, fully compliant with PRISMA 2020 guidelines, logically developed, and written in clear, precise scientific English. Overall verdict: a strong, solid piece of work acceptable for publication following major revisions.

 

Strengths of the article

- Innovative methodological approach – the combination of systemic (serum kisspeptin) and local (KISS1/KISS1R expression assessed by IHC) markers. The demonstration of concordance between both levels confers biological plausibility and strengthens the argument that kisspeptin truly reflects placental dysfunction rather than merely trophoblastic mass (in contrast to traditional hCG).

- Literature currency – the search was conducted up to the end of 2025.

- Clinical and practical implications – the authors rightly emphasize the need for assay standardization and large-scale prospective cohort studies before clinical implementation.

- Tabular presentation of results – clear, concise, and effectively summarizing the key findings.

- All cited studies are real and from reputable sources.

 

Weaknesses and Areas Requiring Improvement

- Incomplete presentation of results - The authors state that 12 studies were included, yet the tables (Tables 1, 2, and 3) display only 5–6 of them. A complete list of all included studies is missing (best placed in a Supplementary Table or as an expanded Table 1).

- Furthermore, a detailed PRISMA flow diagram is absent; only a textual description is provided.

 

Minor methodological inconsistencies

- Inclusion criteria specify “only human studies.” However, Li et al. (2017) is described as an “Experimental RSA model.” In reality, this was a study performed on human trophoblasts obtained from patients with a history of recurrent spontaneous abortion (RSA); this should be clarified.

- Risk-of-bias assessment (Newcastle–Ottawa Scale + QUADAS-2) is rated as “low to moderate,” yet no detailed per-study evaluation table is provided (a requirement under PRISMA guidelines).

 

The concept of “personalized pharmacy”

The manuscript repeatedly refers to the concept of “personalized pharmacy”, In its current form, it is not entirely clear how the presented findings translate into a personalized therapeutic approach. I would therefore ask the authors to clarify what they specifically mean by “personalized pharmacy” in the context of this study and how the investigated mechanisms support a personalized or patient-tailored treatment strategy.

 

Minor editorial issues and additional comments

- Table 1 contains only 6 entries despite the declared inclusion of 12 studies.

- Incomplete data in the tables (e.g., Table 2 presents only 2 studies, although the text states ≥3).

 

kind regards,

 

Author Response

We sincerely thank the reviewer for the thorough, constructive, and highly positive evaluation of our manuscript. We greatly appreciate the recognition of the methodological approach integrating circulating and tissue-level evidence, as well as the valuable suggestions for improving completeness and clarity. All comments have been carefully addressed as detailed below.

1. Incomplete presentation of results

Comment: The manuscript states that 12 studies were included, yet the tables display fewer.

Response: We thank the reviewer for this important observation. Upon careful revision, we clarified that the number of eligible primary clinical and translational studies meeting the inclusion criteria is limited. The manuscript has been corrected to reflect the exact number of included studies (n = 5). All tables have been revised accordingly to ensure full consistency between the text, tables, and included evidence base.

2. PRISMA diagram missing

Comment: A detailed PRISMA flow diagram is absent.

Response: We thank the reviewer for this comment. A PRISMA 2020 flow diagram has now been added as Figure 1 to visually present the study selection process, including identification, screening, eligibility assessment, and final inclusion of studies (n = 5). This improves transparency and compliance with reporting standards.

3. Human-only inconsistency (Li et al.)

Comment: Li et al. is incorrectly described as an experimental model.

Response: We thank the reviewer for this clarification. The study by Li et al. has been reclassified as a human tissue-based translational study involving trophoblast samples derived from patients with recurrent spontaneous abortion. This correction ensures full consistency with the human-only inclusion criteria.

4. Risk of bias table missing

Comment: No detailed per-study risk-of-bias table is provided.

Response: We appreciate this important comment. A detailed per-study risk-of-bias table has now been added as Supplementary Table S2, based on the Newcastle–Ottawa Scale and QUADAS-2 domains. The text has been updated accordingly.

 

5. Personalized pharmacy concept

Comment: The concept of “personalized pharmacy” needs clarification.

Response: We thank the reviewer for this valuable comment. The manuscript has been revised to more clearly define “personalized pharmacy” in the context of this study. We now explicitly describe it as encompassing individualized monitoring, biomarker interpretation, patient-specific counselling, and interdisciplinary support, rather than direct therapeutic decision-making. A dedicated paragraph has been added in the Discussion to clarify this perspective.

 

6. Tables incomplete

Comment: Tables contain incomplete data.

Response: We thank the reviewer for this observation. All tables have been revised to reflect the exact number of included studies (n = 5). Table 1 now presents all included studies, while Tables 2 and 3 clearly indicate that they represent subsets of circulating and tissue-based evidence, respectively.

 

 

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript was improved, but still review based on 5 five publications is poor. I am suggesting to add : Short Review.

Author Response

The manuscript was improved, but still review based on 5 five publications is poor. I am suggesting to add : Short Review.

Thank you for this valuable suggestion. We appreciate the reviewer’s comment and agree that this modification would improve the clarity and scientific quality of the manuscript. Accordingly, we will incorporate this suggestion into the revised version of the article.

Reviewer 4 Report

Comments and Suggestions for Authors

Thank you for the corrections - the work is accepted for publication in its current form.

Author Response

Thank you for the corrections - the work is accepted for publication in its current form.

 

We sincerely thank the reviewer for the careful evaluation and valuable comments provided throughout the review process. Your suggestions significantly improved the clarity and overall quality of the manuscript and helped make the work stronger and more refined. We greatly appreciate the positive assessment and the acceptance of our work for publication in its current form.