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Losartan Cuts Clinically Significant Paclitaxel Neuropathy Incidence by More Than Half
In a randomized controlled trial of 89 women with early-stage breast cancer, daily losartan reduced the incidence of grade ≥2 paclitaxel-induced peripheral neuropathy from 86.4% to 33.3% (p < 0.001) and delayed its onset by nearly 30 days (HR 0.2, 95% CI 0.11–0.35). These findings position losartan as a potentially viable, low-cost prophylactic candidate for a toxicity that currently has no established preventive treatment.
What Was Studied
The trial investigated whether daily oral losartan, an angiotensin-II receptor blocker, could reduce the incidence and severity of paclitaxel-induced peripheral neuropathy (PIPN) in breast cancer patients undergoing weekly chemotherapy. The question carries clinical urgency because PIPN persists chronically in more than 60% of affected individuals and remains a leading cause of dose reduction or treatment discontinuation, yet no prophylactic intervention has demonstrated sufficient efficacy to enter standard practice.
How It Was Studied
This was a single-center, open-label, randomized controlled trial enrolling women with early-stage breast cancer who were scheduled to receive weekly paclitaxel at 80 mg/m². A total of 89 participants were randomly assigned to either the losartan group (n = 45) or standard care alone (n = 44). The trial ran from December 2023 to December 2024 and assessed outcomes at 12 weeks, capturing neuropathy grade, time to onset, quality of life, pain scores, and nerve growth factor (NGF) levels. The comparator arm received standard supportive care without any experimental neuroprotective agent.
What Was Observed
- Neuropathy incidence was dramatically lower with losartan: only 33.3% of patients in the losartan arm developed grade ≥2 neuropathy, compared with 86.4% in the control arm (p < 0.001). This represents an approximately 80% reduction in the relative risk of clinically significant neuropathy, a difference substantial enough to be considered meaningful even by conservative standards.
- Losartan also delayed neuropathy onset by approximately 30 days: the median time to grade ≥2 neuropathy was 73.27 days in the losartan group versus 43.75 days in controls, reflecting about an 80% lower hazard of developing neuropathy at any given time point (HR 0.2, 95% CI 0.11–0.35). The confidence interval does not cross 1.0, indicating a statistically robust effect.
- Patient-reported quality of life was markedly better in the losartan group at 12 weeks: FACT/GOG-NTX scores averaged 31.87 ± 6.43 versus 15.45 ± 10.04 in controls (p < 0.001), where higher scores reflect better neurotoxicity-related quality of life. Median pain intensity was also substantially lower (VAS score 3 vs. 8; p < 0.001), suggesting a clinically meaningful difference in patient experience.
- NGF levels and adverse event profiles were comparable between groups, indicating that losartan did not measurably alter circulating nerve growth factor as a proposed mechanism, and that its addition to chemotherapy did not introduce new or excess toxicity.
Why This Matters
There is currently no approved pharmacological prophylaxis for PIPN, leaving clinicians with few options beyond dose modification when neuropathy becomes disabling. The repurposing of losartan — a widely available, inexpensive, and well-characterized antihypertensive — could represent a practical and accessible intervention if these results hold in larger studies. This trial adds rare positive evidence to a field that has seen multiple candidate agents fail, and it provides a mechanistic rationale centered on attenuation of neuroinflammation via angiotensin-II pathway blockade.
How to Read This Result
The findings are promising in direction and magnitude, but the single-center, open-label design and modest sample size assign this result a medium confidence level; subjective outcomes such as pain and quality of life are particularly vulnerable to performance and detection bias in the absence of blinding, and independent replication will be essential before clinical adoption.
Limitations
The most important methodological constraint is the open-label design: neither patients nor clinicians were blinded to treatment allocation, which creates a meaningful risk of bias in the assessment of patient-reported outcomes including pain scores and quality-of-life questionnaires. Additionally, enrollment at a single center limits the generalizability of findings to broader or more diverse patient populations, and the relatively small sample size reduces the precision of secondary outcome estimates. The authors themselves acknowledge that larger, multicenter, ideally blinded trials are required for validation.