Assess effect and safety of intra-arterial autologous mesoangioblasts administration to the upper arm of m.3243A>G mutation carriers

Mitochondrial disorders are progressive, often fatal multisystem disorders, in
20-25% of the cases caused by heteroplasmic mutations in the mitochondrial DNA
(mtDNA). Epidemiological studies have shown that mtDNA disorders affect about 1
in 10,000 of the general population, inducing significant morbidity and
mortality and high health and societal costs. Clinical manifestations are most
prominent in organs with a high energy demand, like muscle and brain. At this
moment, there is no effective treatment known to influence the disease process
or manifestation. Myogenic stem cell-based therapies complementing and
repairing defective muscle cells and fibres, are highly promising to combat the
myopathy and exercise intolerance which affect >50% of heteroplasmic mtDNA
mutation carriers. Myogenic stem cells called mesoangioblasts (MABs), are
currently the only myogenic precursors that fulfil all criteria to be used as
advanced therapy medicinal product (ATMP) for systemic treatment, namely good
ex vivo proliferation capacity, high myogenic capacity and a capability to
cross blood vessels, allowing intra-arterial (systemic) delivery towards
affected muscle. Both genetically corrected autologous and allogeneic MABs
transplantation has been performed in mice and dog models of Duchenne Muscular
Dystrophy (DMD) and three MABs administrations resulted in significant
regeneration of dystrophin-positive muscle fibers in both models. In humans,
allogeneic MABs transplantations have been performed in six patients with
Duchene muscular dystrophy (DMD). This study demonstrated that the treatment
was relatively safe, and that some dystrophin was produced by the new muscle
fibers, although not sufficient for functional improvement, most likely to a
suboptimal design and advanced stage of disease. Subsequently, our phase I/II
study (EudraCT no.2016-001258-16) using autologous MABs demonstrated that a
single intra-arterial administration of 50x10E6/kg autologous MABs as an
advanced therapy medicinal product (ATMP) was safe and that an increase in
number of MABs was observed in the transplanted muscle. However, based on the
animal studies mentioned above, infusion of minimal three MABs doses at 4-6
weeks interval are needed to achieve functional improvement.

This study has been transitioned to CTIS with ID 2024-515129-27-00 check the CTIS register for the current data.

In our phase IIa trial we will determine the effect and safety of three MABs
administrations in the m. biceps brachii in m.3243A>G patients with a
functional deficit in this muscle. The phase IIa trial will consist of three
administrations of autologous MABs at intervals of 4-6 weeks. One day before
each MABs administration, eccentric exercise of both arms will be performed to
induce muscle damage. Administration of autologous MABs (mutation load <25%)
will be performed intra-arterially (i.a.) via a catheter in the femoral artery
in the left arm of six m.3243A>G patients. These patients have a skeletal
muscle mutation load >25 higher than the mutation load in MABs, and a reduced
muscle strength and increased muscle fatigue in the m. biceps brachii (BB). The
first primary objective is to assess the effect of three intra-arterial
administrations of autologous MABs with respect to improving muscle strength
and reduce fatigue of the treated BB compared to the untreated BB. The
co-primary objective is safety of the ATMP (three administrations) and the
intra-arterial administration procedure to the left upper arm, by checking for
(S)AEs, vascular obstructions, and changes in neurological vital signs.
Secondary objectives are to assess changes in muscle mass of the treated and
untreated BB muscle, and microscopic changes and m.3243A>G mutation load at
tissue level in treated biceps brachii (BB) muscle at baseline and after
treatment.

Mono-center prospective open label intra-subject controlled phase IIa clinical
study.

3x intra-arterial administration (4-6 weeks interval) of 50 million
mesoangioblasts/kg in left arm (m.3243A>G <25%). Total MABs dose after 3
administrations will be 150 million * 5,0/5,7% of body weight (=weight arm
female/male).

Out of the maximal 20 patients, the first 6 eligible patients will enrol the
clinical study and visit the hospital 8 times in total. The not-eligible
patients will visit the MUMC once.

Visit 1: Screening visit (n=20 (maximal) of which the first six eligible will
be selected for intervention study (visit 2 - 8), consisting of neurological
and physical examination, assessment of muscle strength/fatigue of the biceps
brachii (BB) muscles by hand-held dynamometry. Only if BB muscle
strength/fatigue is within criteria to be included in study, subsequent
procedures will be performed: An ECG, a venous blood sample and a 130 mg BB
muscle biopsy for mutation load analysis, isolation and expansion of MABs at
GMP facility and baseline measurements. Try-out on the Biodex dynamometer will
be performed, which will be used to assess the maximal eccentric exercise
training that will be executed at visit 2, 4 and 6, and determine muscle
strength arm [1-repetition maximum (1RM)].
Visit 2/4/6: The Biodex Dynamometer will be used to measure the force and
fatigue of the BB muscles. This will be followed by a maximal bout of eccentric
exercise of both BB muscles 1 day prior to transplantation to trigger migration
of the mesoangioblasts to the muscles upon intra-arterial delivery. At visit 2,
MRI analysis (or CT scan in case of metal implant) of both upper arms will be
performed to determine baseline measurements.
Visit 3/5/7 (28 - 40 day interval between these visits): The Biodex Dynamometer
will be used for strength measurements of the BB muscles to assess
exercise-induced strength loss. This flow-adjusted dose of autologous
mesoangioblasts (50x10E6/kg muscle) will be administered in left axillary
artery via a catheter in the right femoral artery under local sedation. Pre-
and post-infusion angiography will be performed, and an 8-hour hospital
monitoring of neurological vital signs following administration.
Visit 8 (28 - 40 days after visit 7): Physical and neurological examination of
the patient will be performed. Post-intervention MRI (or CT scan) and Biodex
dynamometer measurements will be performed of the treated and untreated BB
muscles. A muscle biopsy will be collected of left (treated) BB muscle to
assess efficacy of MABs administration.

The burden and risk associated with participation in the intervention study (6
patients) will consist of three times eccentric exercise BB muscles, eight
strength measurements BB muscles (plus one baseline assessment/try-out), the
collection of in total three skeletal muscle samples, two MRIs of the upper
arms (or 2 CT scans in case of metal implant), 11 times venous blood sampling
(10x10ml and 1x20ml), three intra-arterial administrations of autologous MABs,
three pre- and post-angiographies, three 8 hour observations in the hospital.
We expected the follow-up burden to be limited. Eccentric exercise can cause
some muscle strain for a couple days, comparable with workout at the gym.
Muscle biopsies can be painful in some cases. Infections and bleeding
afterwards are possible, but rare. To minimize the burden, the small (~30mg)
muscle biopsy collected at visit 9 will be collected using a Pro-Mag I or
Mission 14GA core biopsy instrument, which is a fast and routinely used
procedure to harvest a small muscle fragment with patient burden being limited
to the time of the procedure. The larger ~130 mg needle biopsy is also well
tolerated, has a low complication rate, and is preferred by patients over
surgical biopsy, according to literature. Intra-arterial injection can cause
bleedings and an allergic reaction to the contrast agent is possible. In our
first phase I/II study, intra-arterial injection of one dose of autologous
mesoangioblasts (50*10E6/kg) in lower leg of m.3243A>G mutation carriers, the
collection of muscle biopsies was well-tolerated and administration of
autologous MABs was safe, despite some discomfort during administration itself.
One grade II adverse event (pain, rash and itching of transplanted lower leg)
was observed during the administration of ICG-labelled MABs, which resolved
spontaneously within couple of days. No (later-onset) complications were
observed during the 24h hospital observation. Given this, and the fact that
majority of injected cells are cleared from the circulation within 6 hours,
patients are observed in the hospital for 8 hrs after i.a. infusion in this
trial. Medication to react in case of an adverse event (thrombosis,
anaphylactic shock, allergic reaction) is available.