Transcript Fingolimod (Gilenya) - University of Missouri

Fingolimod (Gilenya)
Presented by Matthew Brickey, Tim
Robinson, Tom McGinnis, and Katie
Youmans
Outline
•
•
•
•
•
•
Disease: Multiple Schlerosis
Discovery of Fingolimod-Gilenya
Synthesis and lead modification
Mechanism of action
Pharmacology
Questions
Multiple Sclerosis
• Degenerative nerve disease
• Characterized by defective immune
system response resulting in nerve
damage
• Cause is unknown
• Difficult diagnosis
Multiple Sclerosis (MS)
4 types of MS
• Relapsing-remitting (RR)
• Primary Progressive (PP)
• Secondary progressive (SP)
• Progressing relapsing (PR)
• RR often progresses into SP over time
DISCOVERY
Initial Antifungal Agents
• Cyclosporin A-reported in 1976 (fungus origin)
• FK506-isolated in 1987 (bacterium origin)
• These set up a foundation for the screening of
new fungi and other microbes in the pursuit of
new immunosuppressants.
Studying Isaria sinclairii
• Tetsuro Fujita began focusing on Isaria
sinclairii in the late 1980s and early 1990s.
• This fungus is native to Asia, mainly China,
Korea, and Japan.
• Classified as an entomopathogenic fungus.
Isaria sinclairii fungal development
• Spreads by infecting insect larvae with its
fungal spores
• Acts as a parasite, growing in and ultimately
killing the insect
• Afterwards, colonizes the insect cadaver and
develops white fruiting bodies (6cm tall)
• Fruits in spring and summer
In Vitro Assay
• To screen for immunosuppressive activity
• Fujita used a mouse allogeneic mixed
lymphocyte reaction (MLR) assay
• Spleen cells from two different strains of
mice were cocultured and alloantigen was
added to stimulate T-cell proliferation
• Samples were evaluated for inhibition of
proliferation of T-cells (reported as IC50
value)
In Vivo Assay
• Performed by transplanting the dorsal skin of
one rat (strain LEW) to the lateral thorax of
the second rat (strain F344)
• Daily intraperitoneal administration until the
skin grafts were rejected (90% necrosis)
• Compounds were scored on their ability to
prolong rat skin graft survival.
Importance of Assays
• Lead to the eventual development of
fingolimod
• The evaluation process guided the isolation of
a compound with immunosuppressant activity
– They called it ISP-I (below)
ISP-I
• Identical to previously isolated antifungal agents
– Myriocin and thermozymocidine
• Pros:
– Found to be 5-10 fold more potent than cyclosporin A
in the MLR assay
– Also prolonged rat skin graft survival better.
• Cons:
– Found to be toxic at a smaller dose than Cyclosporin A
– Poorly soluble
Improving ISP-I
• Goal:
– To simplify the structure and improve the physical
characteristics (e.g. solubility) and biological
function
• Between 1995 and 1998, around 50 different
analogues were reported, with published
results from both in vitro and in vivo assays
ISP-I-28
• First analogue of interest
• Less toxic, prolonged survival, but less potent
in MLR assay
• Reduced carboxylic acid and 14-ketone to
alcohols
Next Steps
• Removed three hydroxy groups, ISP-I-36
• Improved activity and survival
• Shortened chain to 14 carbons to create ISP-I-55
• More potent immunosuppressant in both in vivo and
in vitro, double survival time in skin graft assay
Final Modification
• Introduced an aromatic moiety-believed to
improve activity by restricting conformation
• Placement could increase or decrease activity
of drug-one position off 10-fold less potent
• Led to fingolimod, with improved activity, less
toxicity, and better solubility
Synthesis
•
•
•
•
13 methods for Fingolimod, Fingolimod-P
First in 1995
Yields remained at or below 25 % until 2005
Convenient method an improvement on 1995
synthesis, a three step reaction of precursor to
Fingolimod (2008)
Petasis Reaction (Sugiyama, 2005)
•
•
•
•
Five step synthesis
Couples boronic acids, amines, carbonyls
Form amino alcohols
Overall Yield of 28%
Kim 2006
• Start with tris-(hydroxymethyl)aminomethane
(TRIS)
• Convert to aldehyde, then alkyne
• Couple to aryl iodide via Sonogashira reaction
• Hydrogenate, treat with acid, purify
• Cheap, practical, 64% overall yield Fingolimod
Mechanism of Action
v
G Protein Coupled Receptors
The Nuts and Bolts of it
Pharmacology
• Marketed as Gilenya
• First orally active treatment
• Tested on patients with RR-MS
– 60% decreased in relapse rate
• When compared to Injection treatments
growth of new lesions and plaques was
significantly reduced
Questions?