Powell 2010.

Methods	Study design: multi‐centre double‐blind placebo‐controlled RCT Intention‐to‐treat: safety outcomes analysed by ITT, defined as all randomised participants who received at least 1 dose of treatment; efficacy evaluable (EE) population included all participants who received all 3 doses and had at least 1 follow‐up visit after receiving all 3 doses but before having a peripheral vascular intervention or major amputation Country: USA
Participants	Number randomised: N = 27 (AMG0001 n = 21; placebo n = 6) Losses to follow‐up and withdrawals: withdrawal by participant AMG0001 n = 3; placebo n = 0 Age (mean years ± SD): 76.2 ± 1.97 (AMG0001 75.7 ± 2.49; placebo 78.0 ± 1.86) Gender (M): 55.6% (AMG0001 61.9%; placebo 33.3%) Inclusion criteria: appropriately sized ischaemic peripheral ulcer(s) or tissue loss (photographs of wounds reviewed by a vascular specialist before enrolment); 1 or both of the following haemodynamic indicators of severe peripheral arterial occlusive disease: ankle systolic pressure ≤ 70 mmHg or toe systolic pressure ≤ 50 mmHg, poor candidate for standard revascularisation treatment options for peripheral arterial disease based on inadequate bypass conduit, unfavourable anatomy, or poor operative risk Exclusion criteria: patients who, in the opinion of the investigator, had a vascular disease prognosis that indicated they may require a major amputation (at or above the ankle) within 4 weeks of the start of treatment; diagnosis of Buerger’s disease (thromboangitis obliterans); haemodynamically significant aorto‐iliac occlusive disease; revascularisation procedure within 12 weeks before treatment initiation that remained patent (revascularisation procedures evidenced to have failed (completely occluded) for > 2 weeks before treatment initiation were acceptable); deep ulcerations with bone or tendon exposure, or clinical evidence of invasive infection uncontrollable by antibiotics; evidence or history of malignant neoplasm (clinical, laboratory, or imaging), except for fully resolved basal cell carcinoma of the skin (people who underwent successful tumour resection or radiochemotherapy of breast cancer more than 10 years before inclusion in the study, and with no recurrence, could be enrolled, and who had successful tumour resection or radiochemotherapy of all other tumour types more than 5 years before inclusion in the study, and with no recurrence, could be enrolled in the study); proliferative diabetic retinopathy; severe nonproliferative retinopathy; recent (within 6 months) retinal vein occlusion; macular degeneration with choroidal neovascularisation; macular oedema on fundus evaluation by ophthalmologist; intraocular surgery within 3 months; history of ESRD defined as significant by creatinine of 2.5 mg/dL, or receiving long‐term haemodialysis
Interventions	Treatment: HGF plasmid AMG0001, 4.0 mg in 8 intramuscular injections, performed under duplex ultrasound guidance in arteriographically chosen (by a central committee of vascular specialists) locations for each participant based on regions of most severe vascular disease; injection given at 3 time points 2 weeks apart (days 0, 14, and 28) Control: placebo, given in the same manner as treatment
Outcomes	Follow‐up times: 3 months and 6 months Outcomes: Adverse events, ABI and TBI, Rest pain (VAS), Wound healing (change in size of ulcer), Amputation, Survival, QoL
Notes	Study period: August 2005 to August 2008 NCT00189540
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information provided to determine adequate random sequence generation; randomisation ratio was 4:1
Allocation concealment (selection bias)	Unclear risk	Insufficient information provided to determine allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Described as double‐blind and used placebo but did not describe how placebo was disguised for personnel
Blinding of outcome assessment (detection bias) All outcomes	Low risk	ClinicalTrials.gov protocol describes quadruple blinding that included the outcome assessor
Incomplete outcome data (attrition bias) All outcomes	Low risk	Utilised ITT efficacy analysis; ClinicalTrials.gov report includes withdrawals
Selective reporting (reporting bias)	Unclear risk	QoL not reported
Other bias	High risk	Supported by AnGes Inc., for whom 2 of the study authors are consultants Sample size calculation estimated the need for N = 39 evaluable participants (AMG0001 n = 26; placebo n = 13); actual evaluated numbers are far lower due to early termination of the study Reasons given for early termination: (1) sufficient numbers to assess safety, (2) demonstrated a signal of efficacy, and (3) difficulty and slowness of recruitment ClinicalTrials.gov report states that there were "technical problems leading to unreliable or uninterpretable data"