It was announced today that results of the TANGO low-dose cohort compared to controls are positive, both for primary and secondary endpoints. These latest findings were presented by Ehrin Armstrong at the 2019 Vascular Interventional Advances conference (VIVA) in Las Vegas, USA (4–7 November). According to Armstrong, perivascular temsirolimus is being developed as a “viable alternative” to prevent restenosis after below-the-knee (BTK) peripheral artery interventions, and TANGO high-dose data is “forthcoming”.
The TANGO trial is a phase II, dose escalation, double-blinded trial comparing the delivery of temsirolimus to saline control in patients with severe claudication or critical limb ischaemia. This is the first US trial to investigate a sirolimus analogue to improve the durability of peripheral revascularisation procedures. Armstrong commented that the present results warrant a move to Phase III trials.
The purpose of the trial is to limit neointimal hyperplastic tissue growth into the artery after endovascular BTK revascularisation procedures, where paclitaxel-coated balloons have had limited success.
Results are now available comparing Bullfrog micro-infusion device (Mercator MedSystems) delivery of either low-dose temsirolimus treatment (0.1mg/mL; n=20) or saline control (n=20) into the perivascular tissue around lesions subsequent to revascularisation. Patients (Rutherford category 3–5) with up to 30cm-long BTK lesions were enrolled in the study.
The primary safety endpoint was 30-day freedom from major adverse limb event or postoperative death, and no events were observed. The primary efficacy endpoint was improvement in 6-month transverse view vessel area loss, an angiographic measure that uses the opacified area of the lesion to approximate the neointimal volume.
At six months, excluding subjects with unstented severe dissections in their target lesion, transverse view vessel area loss improved to 19% in treatment subjects compared to 38% in controls. With respect to secondary endpoints, six-month freedom from target lesion failure was reported in 58% (11/19) of treatment subjects compared to 42% (8/19) of controls, favouring treatment by a relative 38%. In patients with total occlusions at baseline, 78% (7/9) of treatment subjects and 25% (2/8) of control subjects were free from reocclusion at 6 months.
In treatment subjects with wounds upon enrolment or who developed wounds on their target limb during the study, 71% (5/7) of treatment subjects had full healing of wounds by 12 months without the need for clinically driven target lesion revascularisation, whereas 44% (4/9) of control subjects had wound healing without prior clinically driven target lesion revascularisation.