Shanghai Easy-Flow Medical Tech Co., Ltd. ("Easy-Flow™") has officially announced that its independently developed EF-SiroNova™Sirolimus Drug Eluting Balloon Dilatation Catheter has been approved for market release by NMPA.It is indicated for percutaneous transluminal angioplasty (PTA) of infrapopliteal arteries, including the tibioperoneal trunk, anterior tibial artery, peroneal artery, and posterior tibial artery.

Infrapopliteal atherosclerosis often involves multiple arteries below the knee and typically presents as multilevel disease. Clinically, it frequently manifests as chronic limb-threatening ischemia (CLTI), characterized by rest pain, ulcers, or gangrene, ultimately leading to amputation. Effective revascularization of infrapopliteal arteries is critical for wound healing and reducing amputation rates ^[1]. Drug-coated balloons deliver antiproliferative agents locally to inhibit neointimal hyperplasia, thereby reducing restenosis risk without leaving permanent metallic implants and preserving future treatment options.

Easy-Flow™ has innovatively developed China’s first sirolimus-based DCB specifically tailored for infrapopliteal use. Sirolimus inhibits the mTOR pathway to modulate the cell cycle, suppressing neointimal proliferation while exerting anti-inflammatory effects ^[2]. Due to its low lipophilicity, sirolimus forms drug particles less prone to deposition in the microcirculation, thereby minimizing the risk of “no-reflow” or “slow-flow” phenomena and causing less disruption to distal microvascular perfusion ^[3]—a feature particularly advantageous in infrapopliteal lesions, where microcirculation is fragile and runoff is limited.

Addressing the technical challenges of sirolimus tissue uptake and retention, EF-SiroNova™ employs an innovative “recrystallization + ultrasonic spray coating” process to enable efficient drug delivery tailored for infrapopliteal applications:

    -Uniform and well-defined drug crystal size and morphology form a dense, homogeneous coating, significantly reducing drug loss during long-distance delivery through tortuous infrapopliteal anatomy.

    -Micro-needle-like crystals facilitate rapid drug transfer into the vessel wall upon balloon inflation, enabling efficient delivery and sustained local therapeutic effect.

     -Preclinical studies demonstrated therapeutic drug concentrations in the vessel wall persisting for over 90 days.

The EF-SiroNova™ clinical trial is China’s first prospective, multicenter, randomized, non-inferiority study comparing a sirolimus-coated DCB with a paclitaxel-coated DCB for infrapopliteal disease. Led by Prof. Guo Lianrui from Xuanwu Hospital Capital Medical University, the trial enrolled 221 patients with infrapopliteal lesions, randomly assigned 1:1 to either the EF-SiroNova™ (sirolimus DCB) group or the paclitaxel DCB control group.

At the 6-month follow-up, the primary endpoint—primary patency of the target lesion—was 83.49% in the EF-SiroNova™ group versus 77.68% in the control group (rate difference and 95% CI: 5.81% [–4.59%, 16.20%]; P _{non-inferiority} < 0.001), meeting the pre-specified non-inferiority criterion. At 12 months, no statistically significant differences were observed between the two groups in terms of primary patency, all-cause mortality, major amputation, or clinically driven target lesion revascularization (CD-TLR). Patients in the EF-SiroNova™ group demonstrated sustained clinical improvement.

As China’s first domestically developed, infrapopliteal-specific sirolimus DCB, EF-SiroNova™ addresses key clinical challenges in below-the-knee interventions. By promoting long-term vessel patency, it holds the potential to enhance wound healing and improve limb salvage rates. Looking ahead, this innovative therapy is expected to offer a safe, reliable, and effective treatment option for a broader population of patients with infrapopliteal artery disease.

【1】Chinese Circulation Journal，February，2024，Vol. 39 No.2（Serial No.308）

【2】Rainer Wessely et al. Thromb Haemost 2007; 97: 1003–1012

【3】Sho Torii et al J Vasc Interv Radiol 2018; 29:1041–1049