Oncology · Medical Literature
Coenzyme Q10 as an adjunctive strategy to reduce paclitaxel-induced toxicities in breast cancer: a randomized controlled trial.
Abstract
Paclitaxel is an effective chemotherapeutic agent for breast cancer, but its use is often limited by cumulative toxicities linked to mitochondrial dysfunction and oxidative stress. This study investigated whether Coenzyme Q10 (CoQ10) could mitigate paclitaxel-induced adverse events and improve treatment tolerability. In this open label randomized controlled trial, 60 patients with breast cancer were randomized (1:1) receive weekly paclitaxel (80 mg/m²) for 12 weeks either alone (control group, n = 30) or in combination with oral CoQ10. The primary outcome was the cumulative incidence of grade ≥ 2 peripheral neuropathy. Secondary endpoints included time-to-onset of grade ≥ 2 neuropathy; fatigue, headache, insomnia, musculoskeletal, gastrointestinal, and hematological adverse events; and left ventricular ejection fraction. Adverse events were graded using the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. CoQ10 supplementation was associated with a lower incidence of clinically relevant neuropathy, with grade ≥ 2 events occurring in 68% of the CoQ10 group versus 96% of controls (p = 0.01) with delayed onset of neuropathy (30.0 vs. 20.0 days; log-rank p = 0.005). Significant reductions in severity were also observed for fatigue and insomnia from week 9, and for mucositis, diarrhea, arthralgia, and myalgia from week 11 (p < 0.05). Hemoglobin levels were higher at week 12 (p = 0.009). CoQ10 was associated with preservation of left ventricular ejection fraction (p = 0.005). CoQ10 supplementation during paclitaxel therapy was associated with reduced treatment-related toxicities, preservation of hematologic parameters, and favorable changes in left ventricular ejection fraction, with favorable tolerability. ClinicalTrials.gov (NCT06570811) on August 26, 2024. Available at: https://clinicaltrials.gov/study/NCT06570811 .
Clinical relevance
In women with breast cancer receiving weekly paclitaxel (80 mg/m²) following standard anthracycline-cyclophosphamide chemotherapy, does adjunctive oral CoQ10 (ubiquinol 400 mg/day) reduce the cumulative incidence and delay the onset of grade ≥2 peripheral neuropathy and other paclitaxel-induced toxicities compared with paclitaxel alone? __SNAPSHOT__ {"studyDesign":"Open-label, parallel-group randomized controlled trial (NCT06570811)","setting":"Single center; Egypt (institution type not reported in abstract); registered August 26, 2024","sampleSize":"n=60 (CoQ10 group: n=30; control group: n=30)","population":"Female patients aged ≥18 years with newly diagnosed breast cancer, ECOG performance status 0–2, who had completed four cycles of standard doxorubicin (60 mg/m²) plus cyclophosphamide (600 mg/m²) and remained eligible for weekly paclitaxel. Excluded: pregnancy or breastfeeding, hereditary muscle disorders, diabetes mellitus, alcoholism, thyroid dysfunction, metastatic disease, advanced liver disease (LFTs >3× ULN or cirrhosis), chronic kidney disease, or known allergy to CoQ10 or related compounds.","intervention":"Weekly paclitaxel 80 mg/m² IV for 12 weeks PLUS oral CoQ10 (ubiquinol, Dozova CoQ10 Ubiquinol®, Zeta Pharma, Egypt) 200 mg twice daily (total 400 mg/day) administered with meals","comparator":"Weekly paclitaxel 80 mg/m² IV for 12 weeks alone (no placebo control)","primaryOutcome":"Cumulative incidence of grade ≥2 peripheral neuropathy, graded per CTCAE v5.0","followUp":"12 weeks (duration of paclitaxel treatment); post-treatment follow-up not reported","fundingSource":"Not reported in abstract or available text excerpts"}
Key findings
Primary outcome: Grade ≥2 peripheral neuropathy occurred in 68% of the CoQ10 group versus 96% of controls (p=0.01; absolute risk reduction [ARR]=28% [calculated]; relative risk reduction [RRR]=29% [calculated]; number needed to treat [NNT]≈4 [calculated]). Time to onset of grade ≥2 neuropathy was significantly delayed in the CoQ10 group (median 30.0 days vs. 20.0 days in controls; log-rank p=0.005). Secondary outcomes: Statistically significant reductions in severity were observed for fatigue and insomnia from week 9 onward, and for mucositis, diarrhea, arthralgia, and myalgia from week 11 onward (all p<0.05). Hemoglobin levels were significantly higher in the CoQ10 group at week 12 (p=0.009). Left ventricular ejection fraction (LVEF) was preserved in the CoQ10 group (p=0.005). Specific values for LVEF, hemoglobin, and individual toxicity grade distributions beyond grade ≥2 neuropathy incidence are not reported in the available abstract. Effect sizes, confidence intervals, and NNT/NNH for secondary endpoints were not reported. No treatment-limiting adverse events attributed to CoQ10 were reported; complete safety data are not available from the abstract.
Practice implications
This trial demonstrates a statistically significant reduction in the cumulative incidence of clinically relevant (grade ≥2) paclitaxel-induced peripheral neuropathy and a meaningful delay in its onset with adjunctive oral CoQ10 ubiquinol 400 mg/day. The calculated NNT of approximately 4 is numerically compelling; however, this must be interpreted with caution given the small sample size (n=60) and open-label design without placebo control, which introduces substantial risk of ascertainment and performance bias for subjective toxicity endpoints graded by clinicians and patients aware of their treatment assignment. Secondary benefits—across fatigue, insomnia, gastrointestinal symptoms, musculoskeletal toxicity, hemoglobin preservation, and LVEF maintenance—are hypothesis-generating and broadly consistent with CoQ10's putative mitochondrial protective and antioxidant mechanisms; however, these findings are exploratory and require independent confirmation. Notably, this study does not address whether CoQ10 supplementation affects paclitaxel antitumor efficacy, treatment completion rates, or long-term oncologic outcomes such as disease-free or overall survival. A prior observational study nested within SWOG S0221 raised the concern that antioxidant supplement use during breast cancer chemotherapy may be associated with higher recurrence rates, and this trial was not designed or powered to assess this critical safety signal. Findings apply specifically to women completing sequential AC→weekly paclitaxel regimens and cannot be generalized to other taxane schedules (e.g., dose-dense paclitaxel, docetaxel), other cancer types, or patients excluded by the protocol's comorbidity restrictions (diabetes, thyroid disease, kidney disease). Pre-existing neuropathy was not reported as a stratification variable. Given the open-label design, small sample, single-center Egyptian setting, and absence of efficacy data, practice change is not warranted at this time; results should be considered hypothesis-generating. Only the abstract was available for review, which limits full methodological appraisal. __LIMITATIONS__ Open-label design without placebo control introduces substantial performance and detection bias for all patient-reported and clinician-graded subjective toxicity outcomes (neuropathy, fatigue, insomnia, musculoskeletal, gastrointestinal symptoms),Very small sample size (n=60 total; n=30 per arm) provides limited statistical power for secondary endpoints and precludes reliable subgroup analyses,Single-center study from a single country (Egypt) limits geographic, ethnic, and institutional generalizability,No assessment of antitumor efficacy, chemotherapy completion rates, dose reductions, or long-term oncologic outcomes; CoQ10 antioxidant supplementation during chemotherapy carries a theoretically unaddressed risk of attenuating chemotherapeutic cytotoxicity,Post-treatment follow-up not reported; durability of neuropathy protection and LVEF benefit after CoQ10 discontinuation is unknown,Funding source not disclosed; potential conflicts of interest cannot be assessed,Confidence intervals not reported for any outcome; absolute and relative effect sizes for secondary endpoints not provided,Exclusion of patients with diabetes, thyroid dysfunction, and chronic kidney disease—populations at high baseline neuropathy risk—limits applicability to the patients most vulnerable to paclitaxel-induced neuropathy,The CoQ10 formulation (ubiquinol 400 mg/day) is higher than most prior trials and the specific commercial product used is regionally sourced, raising questions about bioavailability standardization and external applicability,Absence of blinding renders LVEF assessment (objective) more credible than patient-reported symptom endpoints, but even echocardiographic interpretation can be subject to observer bias without blinding,Only abstract available; complete methods, randomization concealment details, adherence data, and full statistical analysis plan cannot be evaluated __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This small, open-label Egyptian RCT found that adjunctive oral CoQ10 ubiquinol (400 mg/day) was associated with a statistically significant reduction in grade ≥2 paclitaxel-induced peripheral neuropathy (68% vs. 96%; NNT≈4 [calculated]) and delayed its onset, with additional benefits across multiple toxicity domains and LVEF preservation. However, the open-label design, absence of placebo, single-center setting, very small sample, and lack of efficacy or long-term outcome data preclude practice change. These results are hypothesis-generating and support the need for a larger, double-blind, placebo-controlled trial that also evaluates oncologic outcomes before CoQ10 can be recommended as routine adjunctive therapy during paclitaxel chemotherapy.