Cancer Cachexia Research and Drug Development: Lessons from Failures and the Promise of Immunomodulation

Comment 1: Figure 1 Clarity: While Figure 1 (Inflammatory mediators and multi-organ involvement) is helpful, some of the text within the diagram is quite small, making it difficult to read without significant zooming. I recommend increasing the font size or simplifying some labels for better readability.

Response 1: Dear Reviewer, thank you for the suggestion. We have increased the font size of the content within figure 1 on page 7 for better readability.

Comment 2: Elaborate on Specific Immunomodulatory Mechanisms: The article introduces immunomodulation as a key future direction and mentions R-ketorolac. Could the authors briefly expand on the general types of immunomodulatory mechanisms (e.g., targeting specific immune cell populations, modulating general immune pathways beyond just cytokines like IL-6)? This would provide a broader context for readers less familiar with the immunology of cachexia.

Response 2:  Dear Reviewer, thank you for your feedback. We have now updated the content as per your suggestion on types of immunomodulatory mechanisms (page 12; highlighted in yellow).

Comment 3: Clinical Relevance of Preclinical Findings: The promising results of R-ketorolac are noted from preclinical studies. While acknowledging that these are early findings, it would be beneficial to briefly discuss the potential translational challenges or next steps for such compounds to move from preclinical models to human clinical trials (e.g., specific biomarkers, patient selection criteria).

Response 3: Dear Reviewer, as per your guidance, we have now incorporated the clinical relevance of preclinical findings in the updated draft (page 22; paragraph 1; highlighted in yellow). Thank you!

Comment 4: Practical Implications for Clinicians: Given the emphasis on multimodal therapy, could the authors offer a brief outlook on how a clinician might begin to integrate these concepts today, even as new drugs are still under development? For instance, what immediate steps could be taken in patient management based on the current understanding of cachexia's multifactorial nature?

Response 4: Dear Reviewer, thank you for your insights. We have now added the content on practical implications for clinicians in the updated draft (page 22; paragraph 2; highlighted in yellow).

Comment 5: Role of Microbiome: The article briefly mentions the gut microbiome's role in inflammation and metabolic dysfunction (Section 2.7). Given its emerging importance in many systemic conditions, a slightly more detailed, perhaps a sentence or two, expansion on how microbiome alterations contribute to cachexia and if any therapeutic interventions (e.g., probiotics, fecal transplants) are being explored in this context, would add value.

Response 5: Dear Reviewer, we have added a section on the role of microbiome in the updated draft ( page 11; paragraph 1; highlighted in yellow). Thank you!

Comments on the Quality of English Language

• Check for consistent use of hyphens in compound terms (e.g., "tumor-host" vs. "tumour-host").
• Ensure consistent capitalization of cytokine names (e.g., "TNF-alpha" vs. "TNFa").
• On page 17, the description for R-ketorolac mentions "reduces IL-6)". This might be better phrased as "reduces IL-6 levels" or "reduces IL-6 production" for clarity.

Response: Dear Reviewer, noted, thank you for your feedback. This has now been modified throughout the draft.

Comment 1: Definition and assessment of cachexia. Progressive functional impairment is an important component of the international consensus definition of cancer cachexia. Nevertheless, many preclinical studies emphasize muscle mass or fiber cross-sectional area, while many clinical studies rely on muscle area measured using cross-sectional imaging. These measurements do not fully characterize muscle health. Muscle quantity is not equivalent to muscle quality or function, and tissue that appears structurally preserved may still have considerable metabolic, contractile or histopathologic injury. For instance, skeletal muscle comprises not only myofibers, but also extracellular matrix, connective tissue, vasculature, innervation, satellite cells and resident or infiltrating immune cells, all of which are impacted during cachexia. The authors discuss mitochondrial dysfunction, but a broader consideration of muscle quality, tissue composition and functional assessment would strengthen the review and its discussion of therapeutic endpoints.

Response 1: Dear Reviewer, thank you for your insights. We have updated definition and assessment of cachexia in the updated draft (page 10; paragraph 1; highlighted in yellow).

Comment 2: Inclusion of GDF-15 trial evidence. A central thesis of the review is that single-pathway therapies are inherently inadequate for treating cancer cachexia. However, the recent phase II trial of ponsegromab demonstrated significant improvements in body weight, appetite and physical activity among patients with elevated GDF-15. These findings do not represent complete reversal of cachexia, and a survival benefit has not been established. However, discussing the selection of a monotherapy directed at an upstream mediator with variable downstream consequences may further support your argument. Please elaborate and discuss.

Response 2: Dear Reviewer, noted, we have now incorporated this information on GDF-15 trials (page 19; section 5.2; highlighted in yellow). Thank you!

Comment 3: R-ketorolac. The review gives R-ketorolac considerable prominence and describes it more favorably than other emerging therapies, yet its proposed mechanism, experimental evidence, and limitations are not examined in comparable detail. The available evidence appears to be principally preclinical and should be identified explicitly as such. The authors should cite the primary R-ketorolac study directly and describe the tumor models evaluated, the evidence for T-cell dependence, the associated reduction in circulating IL-6, and the apparent independence from cyclooxygenase inhibition. R-ketorolac should either be discussed proportionately alongside the other investigational therapies or, if its present prominence is retained, receive a more complete and balanced appraisal of its mechanism, evidentiary limitations, safety and translational status.

Response 3: Dear Reviewer, thank you for your feedback. We have now added the evidence on R-ketorolac in the draft (paragraph 2; page 22; highlighted in yellow).  

Comments on the Quality of English Language

The manuscript is generally well written, and its overall organization and scientific narrative are clear. Nevertheless, it would benefit from careful language editing. There are several subject–verb agreement errors, awkward constructions, and inconsistent scientific terms. “Parabolic studies” should be corrected to “parabiotic studies.” Terminology and formatting should be standardized, including “handgrip” versus “hand-grip,” cytokine nomenclature, and the use of “immune disorder,” “immune system disorder,” and “immune dysregulation.” The frequent use of transitional words such as “further,” “moreover,” “therefore,” and “thus” occasionally makes the prose repetitive or mechanical.

Response: Dear Reviewer, thank you for your inputs. We have now modified this throughout the draft.