PLX-PAD Cell Treatment of Critical Limb Ischaemia: Rationale and Design of the PACE Trial

Eur J Vasc Endovasc Surg. 2019 Apr;57(4):538-545. doi: 10.1016/j.ejvs.2018.11.008. Epub 2019 Jan 25.


Background: Critical limb ischaemia (CLI) is a life threatening condition with a considerable risk of major amputation and death. Besides revascularisation, no treatment has been proven to reduce the risks. Therapeutic angiogenesis by gene or cell therapy has not demonstrated definitive evidence in randomised controlled trials. PLX-PAD is an "off the shelf" allogeneic placental derived, mesenchymal like cell therapy, which, in preclinical studies, has shown pro-angiogenic, anti-inflammatory, and regenerative properties. Favourable one year amputation free survival (AFS), and trends in reduction of pain scores and increase of tissue perfusion have been shown in two small, open label, phase I trials.

Methods: The PACE study is a phase III randomised, double blind, multicentre, multinational placebo controlled, parallel group study to evaluate the efficacy, tolerability, and safety of intramuscular injections of PLX-PAD cells to treat patients with atherosclerotic CLI with minor tissue loss (Rutherford Category 5) up to the ankle level, who are unsuitable for revascularisation or carry an unfavourable risk benefit for that treatment. The study will enroll 246 patients, who after screening are randomised in a ratio of 2:1 to treatment with intramuscular injections of PLX-PAD 300 × 106 cells or placebo on two occasions, eight weeks apart. The primary efficacy endpoint is time to major amputation or death (amputation free survival), which will be assessed in follow up of at least 12 months and up to 36 months.

Conclusions: Based on favourable pre-clinical and initial clinical study results, the PACE phase III randomised controlled trial will evaluate placenta derived PLX-PAD cell treatment in patients with critical limb ischaemia, with an unfavourable risk benefit for revascularisation. NCT03006770.

Keywords: Cell therapy; Critical limb ischaemia; Trial design.

Publication types

  • Clinical Trial Protocol

MeSH terms

  • Aged
  • Aged, 80 and over
  • Allogeneic Cells / physiology*
  • Amputation
  • Clinical Trials, Phase II as Topic
  • Critical Illness
  • Double-Blind Method
  • Female
  • Humans
  • Ischemia / diagnosis
  • Ischemia / mortality
  • Ischemia / physiopathology
  • Ischemia / surgery*
  • Limb Salvage
  • Lower Extremity / blood supply*
  • Mesenchymal Stem Cell Transplantation / adverse effects
  • Mesenchymal Stem Cell Transplantation / methods*
  • Mesenchymal Stem Cell Transplantation / mortality
  • Middle Aged
  • Multicenter Studies as Topic
  • Placenta / cytology*
  • Pregnancy
  • Progression-Free Survival
  • Randomized Controlled Trials as Topic
  • Time Factors
  • Transplantation, Homologous
  • Treatment Outcome

Associated data