Adult mesenchymal stromal cells to regenerate the neonatal brain: the PASSIoN trial (Perinatal Arterial Stroke treated with Stromal cells IntraNasally)

Cerebral palsy (CP) is a heterogeneous syndrome with a prevalence between 1.0
and 2.4 per 1000 live births. Perinatal arterial ischemic stroke (PAIS) is one
of the most important etiologies for CP and occurs in about 1 per 2300 live
births. Unilateral spastic cerebral palsy (USCP), occurring in about 60% of the
infants and other common problems including epilepsy, cognitive, speech and
behavioral problems. Because of the large and long-lasting burden of the
consequences of PAIS for patients and society, development of a treatment
strategy for these vulnerable infants is urgently needed. The overall aim of
this project is to fill this void by developing an adult mesenchymal stem cell
(MSC) based treatment strategy to reduce the life-long consequences of neonatal
brain damage. We have already demonstrated in a mouse model of neonatal
ischemic infarction that intracerebral application of murine adult bone
marrow-derived MSC markedly improves outcome. Treatment with MSC reduced
infarct size by >45%, stimulated formation of new neurons and oligodendrocytes,
partially restored cortico-spinal motor tract activity, and improved
sensorimotor outcome. Moreover, our most recent findings indicate that MSCs can
be successfully administered to the brain via an efficient non-invasive route,
the nasal route. Upon application to the nasal mucosa, MSCs cross the cribiform
plate and migrate into the brain via the rostral migratory route. The MSCs
subsequently accumulate predominantly in the infarcted area. The migration of
intranasally administered MSCs was also confirmed in experiments with neonatal
primates. Notably, in rodent models, MSCs delivered via the nasal route reduce
infarct size and improve motor function to the same extent as MSCs administered
intracranially/directly into the brain tissue. In the preclinical part of this
ZonMw study, experimental research to the efficacy and in particular to the
safety of allogenic MSC treatment in the developing species, in which we
focussed on inflammatory activity and formation of malignancies in long-term
studies, did not reveal any negative/adverse effects concerning these
complications in the MSC-treated animals as compared to a non-treated control
group. We furthermore found that it was possible to safely manufacture *off the
shelf* MSCs from healthy human donors in our GMP-accredited Cell Therapy
Facility (CT-F) of the University Medical Center Utrecht and to culture them
for nasal application to term newborns diagnosed with PAIS.

This study will assess safety and feasibility of bone marrow-derived allogeneic
MSCs, as administered by the nasal route, in neonates who suffered from PAIS.
The ultimate goals of the present study is therefore to develop a therapy using
adult human allogenic MSCs to reduce or even to prevent the lifelong
consequences of perinatal arterial ischemic stroke (PAIS)-related brain damage
in this group of term newborns.

A phase I/II, open-label, single-arm, single-center intervention study in the
NICU at the Wilhelmina children*s Hospital / University Medical Centre in
Utrecht of (near-)term newborns *36 weeks of gestation within the first week of
onset of presenting clinical symptoms. All eligible consecutively admitted
patients with a PAIS involving the territory of the middle cerebral artery will
be treated with allogenic human MSCs. Since (1) our primary objective is safety
and feasibility aspects; (2) the absolute number of PAIS patients will be low,
and (3) determination of the infarction volume and brain growth using advanced
(volumetric) MRI are already routinely used for a long time, we choose to use
this model of investigation. The most important reason to do so is to
accomplish the present study in an acceptable inclusion period of 1-2 years. We
want to emphasize that the principal reason of the present study is to assess
safety and feasibility of MSC treatment in neonates with PAIS. After positive
results from this study it will be probable that treatment with human adult
MSCs provide us with a substantial better outcome using this relatively stable
PAIS model. In the long run this may open the possibility to use MSCs also for
the improvement of treatment modalities of other perinatal complications such
as perinatal hypoxic-ischemic encephalopathy (birth asphyxia) or prematurity.

Based on preclinical data already obtained we anticipate the following ranges
for the treatment protocol: the infants will be treated with one dose of 50
million MSCs via the nasal route within within the first week of onset of
presenting clinical symptoms. More in detail: prior to MSC administration, a
bacterial culture will be taken from both nostrils. Next: 30 minutes prior to
delivery of the cells, the nose will be cleaned with saline using standard
procedures operative in the NICU. Subsequently we will bring a sterile plastic
(e.g. 10cc) syringe alternatevely in both nostrils and drip the MSCs slowly
into the nose. The syringe with MSC will be packaged at the CT-F of the UMC
Utrecht and will be transported to the participating centers by the clinical
research nurse. Newborns of the other participating centers will be transported
to the NICU of the unversity Medical Center Utrecht after MRI confirmation of
PAIS to undergo the procedure as described above. Before and 24 hours after MSC
treatment, blood samples will be drawn from all infants via in-place
arterial/venous catheter.

- The extra burden of the present study for the included infants is considered
to be very limited -to-non-existent given the fact that besides the nasal
treatment to apply the MSCs treatment is not different compared to the acting
treatment protocol. Nasal application of MSCs has been considered as
non-invasive.
- With respect to possible risks of the present MSC treatment, the most
important potential risk factors, inflammatory actions of MSC therapy with
allogenic human MSCs and an increased risk for malignancies, are intensively
investigated in the preclinical part of the present study. No single indication
has been found in experimental research in the developing animal models that
above mentioned complications occur in a higher incidence as compared to
non-MSC-treated animals, whereas the possibilty for a substantial better short-
and long-term outcome seems very realistic on the basis of our previous
experimental research data.