Brain-cell penetrating antibodies for treatment of progressive multiple sclerosis

Abstract. Central Nervous System (CNS) physical injuries, including bacterial or viral infection, can induce
chronic neuroinflammation that is believed to persist for the lifetime of an individual. Among the other
inflammatory events, it is recognized that both acute and chronic activation of the complement pathway plays a
role in the development of secondary brain injuries by inducing neuronal cell loss and synaptic pruning.
Complement over-activation is also firmly implicated in the pathology that underlies the irreversible progression
of multiple sclerosis (MS), a common inflammatory and neurodegenerative disease of the CNS. We hypothesize
that therapeutic inhibition of the complement system and concurrent stimulation of nerve growth may prevent
CNS tissue damage and slow or even block the progression of MS.
Currently, the main obstacle for drug delivery to the CNS is the presence of a selectively permeable blood-brain
barrier (BBB), limiting blood-borne proteinsandapos; entryinto the CNS. To overcome this issue, we have recently
developed several potent camelid-derived nanobodies. The first group of nanobodies can inhibit complement
activation, whereas the second group comprises tyrosine kinase receptor TrkB agonists that mimic the action of
brain-derived neurotrophic factor (BDNF), a growth factor in the brain that promotes neuronal survival, synaptic
plasticity and neurogenesis. Here, we propose to engineer these nanobodies further to facilitate their crossing
of the BBB, thereby gaining the ability to more effectively inhibit the complement cascade and/or stimulate nerve
growth within the CNS.
During phase I, bispecific nanobodies will be produced and validated in in vitro cellular functional assays.
Therapeutic efficacy will be further validated in a well-characterized murine model of progressive MS, the
Theilerandapos;s murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD). To this end, mice will be
treated with control nanobodies, a complement inhibitor nanobody, TrkB agonistic nanobody, or a combination
of the latter two. Once therapeutic efficacy is confirmed in TMEV-IDD, the camelid-derived nanobodies will be
humanized to reduce antigenicity in humans.
Statistically significant improvement in treated mice monitored as an impact on disability progression and CNS
pathology will be the foundation for a phase II submission. The goals of phase II are 1) revalidate the therapeutic
efficacy of humanized antibodies in more extensive experiments, including a detailed analysis of the effect of
sex, age, dose-ranges and delayed treatments, i.e., later than 30 days post-infection, on disability progression,
disease pathology and recovery; 2) to establish manufacturing protocols under current Good Manufacturing
Practice conditions and; 3) to define the biological response, PK/PD, dose-ranging and toxicology in multiple
model animals, including toxicology studies in non-human primates.Narrative: As result of this project, first in class complement inhibiting and neurotropic antibody therapeutics
capable of crossing the blood brain barrier for treatment of progressive multiple sclerosis will be obtained.