Appropriate Surrogate Endpoint in Drug-Coated Balloon Trials for Coronary Artery Diseases

The Consideration of Appropriate Surrogate Endpoint in Premarket Clinical Trials of Drug-Coated Balloon Catheter for the Treatment of Femoropopliteal Artery Stenosis

PURPOSE

Most clinical trials of drug-coated balloon (DCB) for the treatment of femoropopliteal artery stenosis chose 12-month primary patency rate (PPR) or 6-month late lumen loss (LLL) as the primary endpoint. It is still debatable whether 6-month LLL can be served as an appropriate surrogate endpoint for 12-month PPR. This study aimed to identify whether LLL can serve as an appropriate surrogate endpoint in peripheral DCB clinical trials, and shed light on the selection of primary outcome for subsequent confirmatory clinical trials of DCB in the treatment of femoropopliteal artery stenosis.

MATERIALS AND METHODS

The linear regression model was used to evaluate the correlation between 12-month PPR and 6-month LLL. Pooled standardized mean differences (SMDs) and relative gain between the DCB and plain old balloon angioplasty (POBA) group were computed to assess the consistency and surrogacy, using fixed or random effect model as appropriate. The coefficient of variation (CV) was calculated for both endpoints to compare their degree of variation overall and at study level.

RESULTS

A total of 34 studies are eligible for this study. A significant negative linear correlation was found between 12-month PPR and 6-month LLL (R2=0.67, slope=-0.309, p=0.007). The SMD (DCB-POBA) of LLL and PPR was -0.76 (95% confidence interval [CI]: -0.98, -0.54), and 0.59 (95% CI: 0.46, 0.72) (p=0.18). The pooled relative gain of PPR (43%, 95% CI: 35%, 50%) was significantly lower than that of LLL (72%, 95% CI: 61%, 84%) (p<0.001). Coefficient of variation of LLL was larger than that of PPR overall in DCB and POBA groups.

CONCLUSION

Although a significant moderate correlation was observed between 12-month PPR and 6-month LLL, PPR shows more conservative and robust than LLL, which may exaggerate clinical benefits. Late lumen loss should be used discreetly depending on different situations and clinical benefits for patients.

CLINICAL IMPACT

This study addresses the critical issue of primary endpoint selection in clinical trials of drug-coated balloon for femoropopliteal artery stenosis. By elucidating the moderate correlation between 6-month late lumen loss (LLL) and 12-month primary patency rate (PPR), the findings underscore the limitations of LLL as a surrogate endpoint due to its variability and potential to overstate clinical benefits. The study advocates for the use of 12-month PPR as a more robust and conservative endpoint in pivotal trials, particularly for novel devices. These findings provide clinicians with a nuanced understanding of outcome measures, promoting evidence-based decision-making and regulatory alignment to ensure patient benefits in vascular interventions.

Efficacy and safety of drug-coated balloon for de novo lesions of large coronary arteries: Systematic review and meta-analysis of randomized controlled trials

Background

Drug-coated balloon (DCB) is a novel approach to avoiding stent-related complications and has proven effective for the treatment of in-stent restenosis (ISR) and small vessels. However, its role in the treatment of de novo lesions in large vessels is less settled.

Aims

To estimate the efficacy and safety of drug-coated balloon versus stent in the treatment of de novo lesions in large coronary arteries.

Methods

We searched the literature until April 2023. We judged the safety of DCB based on major adverse cardiovascular events (MACEs), cardiac death, all-cause mortality, non-fatal myocardial infarction, target lesion revascularization (TLR), and bleeding event; and efficacy according to late lumen loss (LLL), minimum lumen diameter (MLD). We conducted subgroup analyses according to stent type and whether urgent PCI was required.

Results

A total of 10 RCTs were included. Overall, LLL (mean difference (MD) = -0.19, 95 % confidence interval (CI): -0.32 to -0.06, P = 0.003) was lower in the DCB group than in the Stent arm. This effect was consistent in subgroup analysis regardless of stent type and disease type. In terms of safety indicators, there were no significant differences between DCB and stent. The subgroup analyses found that safety indicators showed no significant differences between DCB and drug-eluting stent (DES), but TLR was lower in the DCB than in the bare metal stent (BMS). Moreover, in ST-elevation myocardial infarction (STEMI), safety indicators and LLL showed no significant differences between DCB and DES, but MLD in the DCB was smaller. While in patients with excluded STEMI, MACE and TLR was lower in the DCB compared with the overall stent.

Conclusions

DCB could be a promising alternative for treating de novo lesions in large coronary arteries with satisfactory efficacy and low risk, superior to BMS and not inferior to DES, with a trend toward lower late lumen loss.

Drug-Coated Balloon-Only Strategy for De Novo Coronary Artery Disease: A Meta-analysis of Randomized Clinical Trials

Backgrounds

Many clinical trials have demonstrated the value of drug-coated balloons (DCB) for in-stent restenosis. However, their role in de novo lesions is not well documented. The aim of this study is to evaluate the safety and efficacy of the DCB-only strategy compared to other percutaneous coronary intervention strategies for de novo coronary lesions.

Methods

The PubMed, Embase, Web of Science, and Cochrane Library Central Register of Controlled Trials (CENTRAL) electronic databases were searched for randomized controlled trials published up to May 6, 2023. The primary outcomes were major adverse cardiac events and late lumen loss.

Results

A total of eighteen trials with 3336 participants were included. Compared with drug-eluting stents, the DCB-only strategy was associated with a similar risk of major adverse cardiac events (risk ratio (RR) = 0.90; 95% confidence interval (CI): 0.59 to 1.37, P = 0.631) and a significant decrease in late lumen loss (standardized mean difference (SMD) = -0.29, 95% CI: -0.53 to -0.04, P = 0.021). This effect was consistent in subgroup analysis regardless of indication, follow-up time, drug-eluting stent type, and dual antiplatelet therapy duration. However, DCBs were inferior to DESs for minimum lumen diameter and percentage diameter stenosis. The DCB-only strategy showed significantly better outcomes for most endpoints compared to plain-old balloon angioplasty or bare metal stents.

Conclusions

Interventions with a DCB-only strategy are comparable to those of drug-eluting stents and superior to plain-old balloon angioplasty or bare metal stents for the treatment of selected de novo coronary lesions. Additional evidence is still warranted to confirm the value of DCB before widespread clinical utilization can be recommended.