The effect of sacubitril/valsartan on functional disability and skeletal muscle injury during breast cancer therapy: insights from the PRADA II trial

Background Anthracycline therapy induces dose-dependent cardiotoxicity and systemic adverse effects, including functional disability. While sacubitril/valsartan attenuates early subclinical myocardial injury during breast cancer therapy, its impact on functional capacity and skeletal muscle injury remains unknown. Purpose To evaluate whether sacubitril/valsartan attenuates anthracycline-induced decline in functional capacity and skeletal muscle injury compared to placebo. Methods PRADA II was a randomised, double-blind, placebo-controlled multicentre trial including 138 women with early breast cancer receiving (neo)adjuvant anthracycline therapy±trastuzumab. Participants were randomised prior to anthracycline initiation to sacubitril/valsartan or placebo for 18 months. The predefined primary outcome of this substudy was change in maximal handgrip strength from baseline to 18 months. Secondary outcomes included changes in 6-minute walk distance and circulating creatine kinase (CK) and myoglobin concentrations. Assessments were performed at baseline, post-anthracycline (Visit 2), and at 18 months (Visit 3). Changes were analysed using generalised linear mixed models, and a two-sided alpha level of 0.05 was applied to the primary outcome. Results Maximal handgrip strength declined in both groups from baseline to Visit 2, with partial recovery at Visit 3 in the sacubitril/valsartan group and continued decline in the placebo group. No significant between-group difference was observed in handgrip strength (between-group change from baseline to Visit 3: -0.3 kg, 95% CI -1.5 to 0.8, p=0.57). However, a greater decline from baseline to Visit 2 was observed with sacubitril/valsartan than placebo, corresponding to a between-group difference of -1.8 kg, 95% CI -3.0 to -0.6. 6-minute walk distance increased from baseline to both follow-up timepoints in the sacubitril/valsartan group, and a transient reduction was observed in the placebo group from baseline to Visit 2. Between-group changes did not differ at Visit 2 (8.8 m, 95% CI -19.3 to 36.9) or Visit 3 (13.6 m, 95% CI -13.3 to 40.5). CK and myoglobin were numerically higher in the placebo group from baseline to Visit 3, however, the confidence intervals for between-group differences included the null value (CK geometric mean ratio 1.17, 95% CI 0.94 to 1.45; myoglobin 1.10, 95% CI 0.98 to 1.23). Temporal changes by randomisation group are shown in Figure 1. Conclusions Sacubitril/valsartan did not significantly attenuate anthracycline-related decline in functional capacity assessed by maximal handgrip strength and 6-minute walk distance or changes in biomarkers of skeletal muscle injury. These findings suggest a neutral effect of sacubitril/valsartan on functional capacity, without challenging its potential cardioprotective role during anthracycline therapy.