Mesoblast Stem Cell Therapy for Patients With Single Ventricle and Borderline Left Ventricle

This is a prospective, single center, safety and feasibility, blinded, randomized trial to
evaluate the use of MPCs in children with complex cardiac anatomy requiring surgical repair.
Patients scheduled to undergo bidirectional Glenn (BDG) with future plans for LV recruitment,
or patients with a history of BDG who are currently scheduled to undergo LV recruitment will
be eligible.

Twenty-four subjects will be enrolled, 12 to the MPC treatment arm and 12 to the control arm
following a 1:1 randomization schema. Randomization will be stratified according to surgeon
to assure random distribution of subjects by surgeon. Families, the biostatistician, all
clinical staff outside the operating room, and research staff completing data analysis will
be blinded to randomization assignment. The PI, operating room staff, and research staff
assisting with delivery will be unblinded to the randomization assignment. Families will be
made aware of their randomization assignment once all subjects have completed their study
Visit 4. Those randomized to the treatment arm will receive MPCs injected directly into the
LV endocardium following clinical surgical maneuvers to recruit the LV (mitral valve repair,
aortic valve repair, and/or resection of endocardial fibroelastosis) or BDG. Those subjects
randomized to the control arm will receive standard LV recruitment or BDG with no injection.

All cardiac tissue acquired as part of a clinically indicated procedure will be collected on
enrolled subjects. Most of the tissue sample will be analyzed at the time of collection
(histology and H+E stain); the remainder will be banked for potential future testing.

Inclusion Criteria:

- Patients with a history of single ventricle palliation (Stage 1 palliation, PA band,
or hybrid procedure) undergoing bidirectional Glenn (BDG) with simultaneous left
ventricle (LV) recruitment procedures or those patients undergoing LV recruitment
procedures will be considered for enrollment.

Exclusion Criteria:

- Patients with current or history of myocardial tumors

- Patients with aortic or mitral atresia

- Patients with a history of high grade ventricular arrhythmias

- Patients with a known allergy to dimethyl sulfoxide (DMSO)

- Patient has known allergy to mouse and/or cow products.

- Patient is prior recipient of stem cell therapy for cardiac repair.

- Patient has received treatment and/or is within an incomplete follow-up treatment of
any investigational cell based therapy within 6 months prior to randomization.