Drug discovery to Market, Sitagliptin case study, Presented at At H( S ) NCB 's Dr L H Hiranandani college of pharmacy , ulhasnagar, India for key note speech in a one day symposium on APi synthesis from lead optimisation to patent filing 17 dec 2016...Dept of Pharmaceutical chemistry
1. A JOURNEY FROM DRUG
DISCOVERY TO MARKET,
SITAGLIPTIN CASE STUDY
SPECIALLY FOR
SEMINAR AT DR. L. H. HIRANANDANI COLLEGE OF PHARMACY, DEPT OF
PHARMACEUTICAL CHEMISTRY, DLHHCOP, ULHASNAGAR, MAHARASHTRA, INDIA
A JOURNEY FROM DRUG
DISCOVERY TO MARKET,
SITAGLIPTIN CASE STUDY
SPECIALLY FOR
SEMINAR AT DR. L. H. HIRANANDANI COLLEGE OF PHARMACY, DEPT OF
PHARMACEUTICAL CHEMISTRY, DLHHCOP, ULHASNAGAR, MAHARASHTRA, INDIA
DR ANTHONY MELVIN CRASTO
PRINCIPAL SCIENTIST
WORLDDRUGTRACKER
17 DEC, 2016
1
3. 3
A National level seminar on 17th December, 2016.
The Theme for the seminar is " API- From Lead
optimization to Patent filing" at Dr. L. H. Hiranandani
College of Pharmacy, Dept of pharmaceutical chemistry,
DLHHCOP, Ulhasnagar, Maharashtra, India
14. 14
• In October 2006, the U.S. Food and Drug Administration
(FDA) approved Sitagliptin as monotherapy and as add-on
therapy to either of two other types of oral diabetes
medications.
• In April, 2007 FDA approved the combination product of
Sitagliptin and Metformin for type 2 diabetes.
• In March, 2007 it was approved in European Union.
• Sitagliptin is currently approved in 70 Countries.
Regulatory Affairs
18. Drug Review.2008;10(2):97-98
• Reduces hemoglobin A1c (HbA1c), fasting and
postprandial glucose by glucose dependant stimulation of
insulin secretion and inhibition of glucagon secretion.
• Sitagliptin is selective inhibitor of the enzyme DPP-4.
• Delays gastric emptying and reduce appetite.
18
SITAGLIPTIN
18
Mechanism of action (MOA)
19. 19
Sitagliptin is a triazolopiperazine based inhibitor of DPP-IV,
which was discovered byMerck. It is a potent (IC50= 18 nM)
and highly selective over DPP-8 (48000 nM), DPP-9
(>100000 nM) and other isozymes. It enhances the
pancreatic β-cell functions, fasting and post-prandial
glycemic control in type 2 diabetic patients. In the crystal
structure with DPP-IV, unlike other substrate-based DPP-IV
inhibitors, the binding orientation of the amide carbonyl of
sitagliptin is reversed, i.e. the aromatic trifluorophenyl moiety
occupies S1 pocket and the β-amino amide moiety fits into
S2 pockets. The amino group forms a salt bridge and
hydrogen bonding interactions with Glu205 and Glu206, and
Tyr662, respectively.
The triazolopiperazinemoiety occupies the S2 extended
pocket and stacks against Phe357.
20. 20
The exhibited binding interactions of the trifluoromethyl
group with the Arg358 and Ser209 are responsible for
its high selectivity profile. The presence of the
trifluoromethyl group in the triazole ring also
improvesthe oral bioavailability in animal models.
Sitagliptin inhibited the plasma DPP-IV up to 80% and
47% at 2 and 24 h, respectively, after a single dose of
25.0 mg in a dose-dependent manner. In a 24-week
study, sitagliptin significantly decreased fasting
glucose levels and HbA1c levels (0.8%) at doses of
100 mg q.d. Thus, sitagliptin is well tolerated and body
weight neutral. It is the first DPP-IV inhibitor in the
class approved by USFDA in 2006 and is used as
either a monotherapy or in combination with metformin
22. 22
http://www.druglead.com/cds/sitagliptin.html
Title: Sitagliptin
CAS Registry Number: 486460-32-6
CAS Name: 7-[(3R)-3-Amino-1-oxo-4-(2,4,5-trifluorophenyl)butyl]-5,6,7,8-
tetrahydro-3-(trifluoromethyl)-1,2,4-triazolo[4,3-a]pyrazine
Additional Names: (2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-
dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-
amine
Molecular Formula: C16H15F6N5O
Molecular Weight: 407.31
Percent Composition: C 47.18%, H 3.71%, F 27.99%, N 17.19%, O 3.93%
Literature References: Selective inhibitor of dipeptidyl peptidase IV (DPP-IV).
Prepn: S. D. Edmondson et al., WO 03004498; eidem, US 6699871 (2003, 2004
both to Merck & Co.); and enzyme inhibitory profile: D. Kim et al., J. Med.
Chem. 48, 141 (2005). Improved process: K. B. Hansen et al., Org. Process Res.
Dev. 9, 634 (2005). Clinical pharmacokinetics and pharmacodynamics: G. A.
Herman et al., Clin. Pharmacol. Ther. 78, 675 (2005). Review: C. F.
Deacon, Curr. Opin. Invest. Drugs 6, 419-426 (2005).
Properties: Viscous oil.
23. 23
Derivative Type: Monophosphate monohydrate
CAS Registry Number: 654671-77-9; 654671-78-0 (anhydrous)
Additional Names: Sitagliptin phosphate
Manufacturers' Codes: MK-0431
Trademarks: Januvia (Merck & Co.)
Molecular Formula: C16H15F6N5O.H3PO4.H2O
Molecular Weight: 523.32
Percent Composition: C 36.72%, H 3.85%, F 21.78%, N 13.38%, O 18.34%,
P 5.92%
Properties: mp 215-217°. [a]D -74.4° (c = 1.0 in water).
Melting point: mp 215-217°
Optical Rotation: [a]D -74.4° (c = 1.0 in water)
24. 24
Orange book
NDA 021995
JANUVIA (SITAGLIPTIN PHOSPHATE)
EQ 25MG BASE
Active Ingredient: SITAGLIPTIN PHOSPHATE
Proprietary Name: JANUVIA
Dosage Form; Route of Administration: TABLET; ORAL
Strength: EQ 25MG BASE
Reference Listed Drug: No
TE Code:
Application Number: N021995
Product Number: 001
Approval Date: Oct 16, 2006
Applicant Holder Full Name: MERCK SHARP AND DOHME CORP
Marketing Status: Prescription
Patent and Exclusivity Information
http://www.accessdata.fda.gov/scripts/cder/ob/
32. DISCOVERY SYNTHESIS
PATENT WO2003004498
SCOTT D EDMONDSON,
MICHAEL H FISHER, DOOSEOP KIM,
MALCOLM MACCOSS, EMMA R PARMEE,
ANN E WEBER, JINYOU XU
32Emma Parmee
Ann E Weber
Scott D. Edmondson
37. 37
The synthesis of 1 was completed using a four-step
through-process
Lactam 5 or ester 13 was hydrolyzed to amino acid 2b with
LiOH in THF/water by either stirring at room temperature
or, in the case of 13, heating to 40 °C.
While the benzyloxy group of 2b could be cleaved by
hydrogenacoupling to triazole 3, the benzyloxy group of 2b
was found to sufficiently tion and then protected with Boc2O
to prevent side reactions during the protect the amino
group to allow the desired amide to be formed.
Thus, triazole 3 was coupled to 2b at 0 °C using EDC−HCl
and N-methylmorpholine (NMM) as base to afford 14 in
>99% assay yield.
51. 51
Omarigliptin (MK-3102, Merck) Omarigliptin is a novel
aminotetrahydropyran based structurally distinct rigid analogue of
sitagliptin in which the central linker of sitagliptin was modified to rigid
cyclohexylamine. It is extremely potent (IC50=1.6 nM) and long acting
with excellent selectivity profile against isopeptidases. It is once-a-week
oral agent rather than once a day like existing therapies in DPP-IV
inhibitor. Omarigliptin binds in the DPP-IV active site very similar to
sitagliptin and share the same interactions. The 2-F atom in the
trifluorophenyl group occupied in S1 pocket shows a hydrogen bonding
with the side chain of Arg125. On the other hand, the
aminotetrahydropyran group binds to S2 pocket where the primary
amine group makes salt bridges with the carboxylates of Glu205 and
Glu206. The fused ring π-π stacks with the side chain of Phe347.[65]
Omarigliptin exhibited a unique PK and pharmacological profile with the
half-life of ~68 h. It markedly lowered the blood glucose levels and
0.57% of HbA1c level at a dose of 25 mg in a 12 week study. It also
exhibited 77- 89% inhibition of plasma DPP-IV up to 168 h and
enhanced two folds of GLP-1 levels. Omarigliptin is generally well
tolerated with excellent safety profiles in healthy subjects. Currently,
omarigliptin is in clinical trial PhaseIII
54. Pharmacokinetics
Bioavailability of Sitagliptin is approximately 87% .
Half life is between 8-14 hours.
It is 38% bound to plasma proteins.
Elimination is mainly through urine.
Drug Review.2008;10(2):97-9854
55. 55
Sitagliptin (Januvia) has a novel structure with β-amino amide derivatives
Since sitagliptin has shown excellent selectivity and in vivo efficacy it
urged researches to inspect the new structure of DPP-4 inhibitors with
appended β-amino acid moiety.
Further studies are being developed to optimize these compounds for the
treatment of diabetes.
In October 2006 sitagliptin became the first DPP-4 inhibitor that got FDA
approval for the treatment of type 2 diabetes. Crystallographic structure
of sitagliptin along with molecular modeling has been used to continue
the search for structurally diverse inhibitors.
A new potent, selective and orally bioavailable DPP-4 inhibitor was
discovered by replacing the central cyclohexylamine in sitagliptin with 3-
aminopiperidine.
A 2-pyridyl substitution was the initial SAR breakthrough since that group
plays a significant role in potency and selectivity for DPP-4.
56. 56
It has been shown with an X-ray crystallography how
sitagliptin binds to the DPP-4 complex:
1.The trifluorophenyl group occupies the S1-pocket
2. The trifluoromethyl group interacts with the side
chains of residues Arg358 and Ser209.
3. The amino group forms a salt bridge with Tyr662
and the carboxylated groups of the two glutamate
residues, Glu205 and Glu206.
4. The triazolopiperazine group collides with the
phenyl group of residue Phe357
57. 57
a) reducing both fasting and postprandial glucose
concentration,
b) clinically meaningful reductions in glycosylated
hemoglobin (HbA1c) levels in type 2 diabetic patients.
• Monotherapy with Sitagliptin 100 mg daily decreases mean
HbA1c by 0.6-0.98%.
CLINICAL EVIDENCE
Drug Review.2008;10(2):97-98
Consultant.2009:S5-11
Pharmacology & Therapeutics.2010;25:328-361
• In very well controlled randomized clinical trials Sitagliptin
(100 mg) treatment significantly improved glycemic control
by
• Improved Homeostasis model assessment of β cell and
Proinsulin-to-insulin ratio.
58. 58
• The recommended dose of Sitagliptin is 100 mg once
daily. It may be taken with or without food.
Recommended Dosage
70. 70
Recently, large pharmaceutical process chemists have relied heavily on the
development of enzymatic reactions to produce important chiral building blocks for
API synthesis. Many varied classes of naturally occurring enzymes have been co-
opted and engineered for process pharmaceutical chemistry applications.
The widest range of applications come from ketoreductases and transaminases, but
there are isolated examples from hydrolases, aldolases, oxidative enzymes,
esterases and dehalogenases, among others.[11]
One of the most prominent uses of biocatalysis in process chemistry today is in the
synthesis of Januvia®, a DPP-4 inhibitor developed by Merck for the management
of type II diabetes. The traditional process synthetic route involved a late-stage
enamine formation followed by rhodium-catalyzed asymmetric hydrogenation to
afford the API sitagliptin.
This process suffered from a number of limitations, including the need to run the
reaction under a high-pressure hydrogen environment, the high cost of a transition-
metal catalyst, the difficult process of carbon treatment to remove trace amounts of
catalyst and insufficient stereoselectivity, requiring a subsequent recrystallization
step before final salt formation.[12][13]
71. 71
Merck’s process chemistry department contracted Codexis, a medium-sized
biocatalysis firm, to develop a large-scale biocatalytic reductive amination for
the final step of its sitagliptin synthesis. Codexis engineered a transaminase
enzyme from the bacteria Arthrobacter through 11 rounds of directed
evolution.
The engineered transaminase contained 27 individual point mutations and
displayed activity four orders of magnitude greater than the parent enzyme.
Additionally, the enzyme was engineered to handle high substrate
concentrations (100 g/L) and to tolerate the organic solvents, reagents and
byproducts of the transamination reaction.
This biocatalytic route successfully avoided the limitations of the
chemocatalyzed hydrogenation route: the requirements to run the reaction
under high pressure, to remove excess catalyst by carbon treatment and to
recrystallize the product due to insufficient enantioselectivity were obviated by
the use of a biocatalyst.
Merck and Codexis were awarded the
Presidential Green Chemistry Challenge Award in 2010 for the development of
this biocatalytic route toward Januvia®.[14]
75. 75
Despite this process being a considerable improvement over its predecessor,
the late-stage hydrogenation was only moderately stereoselective and required
high-pressure conditions [151].
The removal of the metal catalyst by absorption onto a polymer impregnated
with activated carbon and the final recrystallization as the [H2PO4]−
salt led to
reduced yield [151].
76. 76
Enzymatic synthesis of sitagliptin [152].
http://rspa.royalsocietypublishing.org/content/471/2183/20150502
77. 77
The final version of the sitagliptin synthesis avoided this
hydrogenation by using a transaminase enzyme to directly
aminate the prositagliptin diketone precursor with iso-
propylamine (scheme 10) [152], giving a highly enantiopure
product.
The enzymatic process gives a 10–13% increase in overall
yield, a 53% increase in productivity (kgl −1
day −1
), a 19%
reduction in total waste and the elimination of all heavy
metals.
In addition to these environmental advantages, the
biocatalytic process eliminated the need for specialized
high-pressure equipment, leading to reductions in both
capital and running costs.
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