Novel Protease Inhibitors for Hepatitis C
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Transcript of Novel Protease Inhibitors for Hepatitis C
Novel Protease Inhibitors for Hepatitis CBrittany HoltKelly Kerr
4/30/09
Project Goals
Determine manufacturing and commercialization efforts, including the FDA approval process for a new orally available hepatitis C NS3/NS4A protease inhibitor (SCH 503034, Boceprevir)
Determine a novel molecule that can prevent the production and release of infectious HCV particles.
Predict the effectiveness of the new molecule. Compare this to the effectiveness of drugs that are currently being developed.
Modify molecules based on binding affinity tests
HCV Background
Hepatitis C: Background Information4.1 million Americans are affected150-200 million people worldwide
Genotype 1 is the most common genotype in America, Japan, and Europe10,000-12,000 Americans die annually
Current medications lead to a sustained virological response of only 40-50% among patients with Genotype 1 HCVCurrent medications have many severe side effects
HCV Life Cycle
Viral Diversity Demands Drug Diversity
Potent drugs already on marketDozens currently being evaluated
So why another drug? Multiple HCV strains HCV inhibitors select for mutants
Modeling versus Laboratory Research
Study of actual virions is very difficult.Lack of suitable cell culturesExtremely small sizeTrouble isolating virions from serum
HCV proteins in databases!
Target Selection Criteria
Tool Available: Modeling Software
Therefore we must select…a viral protein essential for virion production that has a known active site for its function.
Target: Adsorption
E1 and E2
• glycoproteins • associate with cell surface molecules• high variability
Target: Endocytosis/Fusion/Uncoating
Clathrin-coated pit: Entry
Acidic endosomes: Fusion
Uncoating: HCV RNA release
Target: Translation
RNA travels to the rough ER
5’NTR binds to
ribosomal subunits &initiator tRNA
creating theTranslational active complex (HCV polyprotein synthesis)
Target: Posttranslational Processing
Target: ReplicationNS4B • attaches to ER and • forms membranous web
NS3 helicase • unwinds RNA
NS5B • replicates RNA
NS5A • ?
Target: Assembly and Release
• Viral components • Cellular factors • Lipid droplets
Precise mechanisms are not well understood
NS3 Protease
NS3 protease is a viral protein
NS3P cleaves several essential proteinsNS4A, NS4B, NS5A, and NS5B
Active site: Catalytic triad
NS3 needs NS4A (another viral protein)
Catalytic Triad Mechanism
Acylationpeptide bond is cleaved ester linkage is formed between polyprotein carbonyl C and NS3 protease
Deacylationester linkage is hydrolized enzyme is regenerated
Acylation
Deacylation
Hydrogen bonding of Boceprevir to NS3/NS4A protease
Manufacturing and Commercialization Solution Procedure
FDA Clinical TrialsInvestigational New Drug Application (IND)
Sponsors must show the FDA results of preclinical (animal) testingSubmit proposal for clinical trialsFDA decides on safety of proposed trials
Phase 120-80 volunteersGoals:
Determine side effectsDetermine how the drug is metabolized and excreted
Phase 2Evidence of safety must be shown20-300 patients with HCVGoals:
Determine if the drug works on HCVCompare the drug with a placebo or another medicationEvaluate safetyStudy side effects
Phase 3Evidence of effectiveness must be shown200-3,000 patients with HCVGoals:
Effectiveness in different populationsDosage amountsEffectiveness with other drugs
Gantt Chart – Implementation of Boceprevir
Drug Development
FDA Approval
Phase 1
Phase 2
Phase 3
Current Point in process
Wait on FDA Approval of Drug
Manufacturing Plant Implementation
Build Plant
Install Equipment
Train Employees
Production Process Approval
0 2 4 6 8 10 12 14
Timeline for Implementation of SCH 503034
Timeline (Years)
Gantt Chart Analysis
There is a competitive edge to producing the first drug that makes it through clinical trials
Gain reputation for safety and effectivenessRetain a significant market shareIncreased sales
Synthesis of Boceprevir
Alternate Pathways for Synthesis of Boceprevir
Choosing Schemes to Model
Schemes 1 and 4 were modeled in Super Pro
Comparisons between 1, 2, & 3 were not made
Detailed instructions were given for the Scheme 1Can include every operation for Scheme 1Estimated batch times and costs for Schemes 2 and 3 would be unfairly low
Reagents used in Scheme 1 are more readily obtainable Cost should be more accurate Cost should be lower
Production Goals
Tablets with 250 mg of active ingredient (SCH503034)
Roughly 7.5 million pills per yearEnough for 1% of HCV infected Americans to take once a day for 24 weeks
Minimal batch timeReduce time equipment spends idleReduce losses that would occur if serious error
Superpro Designer Modeling
Super Pro - Flow Chart
Super Pro - Flow Chart
Gantt Chart – Processing Schedule (Synthesis of Boceprevir)
Gantt Chart – Processing Schedule
One batch requires 149 hrs and over 200 operationsEffective batch time = 57.8 hrs
Use AOT scheduleBottleneck is in Reactor 1Options for optimization
Make process continuousAdd a second R1
h8 16 24 32 40 48 56 64 72 80 88 96 104 112 120 128 136 144 152 160 168 176 184 192 200 208 216 224 232 240 248
day1 2 3 4 5 6 7 8 9 10
Cost EstimatesLow Estimate High Estimate Average Most Likely 95% Confidence
Total Cost Preclinical $ 335,000,000 $ 335,000,000 $ 335,000,000 $ 335,000,000 $ 335,000,000
Total Cost Clinical $ 66,366,260 $ 277,294,933 $ 171,830,596 $ 188,845,040 $ 239,703,266 Total Cost Preclinical and Clinical $ 401,366,260 $ 612,294,933 $ 506,830,596 $ 509,642,508 $ 574,801,384 Total Cost Preclinical to Manufacturing Implementation $ 405,379,075 $ 643,897,990 $ 524,638,532 $ 528,080,243 $ 600,385,656 Total Manufacturing Cost per year $ 48,255,217 $ 147,852,741 $ 98,053,979 $ 96,167,982 $ 128,423,759
Fixed Capital Investment $ 4,296,135 $ 36,421,069 $ 20,358,602 $ 14,526,282 $ 30,729,118 Working Capital (6 months) $ 24,127,608 $ 73,926,370 $ 49,026,989 $ 47,239,802 $ 64,252,062 Total Capital Investment $ 52,551,352 $ 184,273,810 $ 118,412,581 $ 128,929,085 $ 159,413,694
Histogram –Preclinical to Manufacturing Implementation and FCI
Should development continue?
Money spent up to this point$509,642,508
Research and DevelopmentPreclinical (Animal) TrialsClinical Trials
Phase 1Phase 2Part of Phase 3
Comparison with current medication costs
Drug DosageDosage for
Average Man Cost per dosageQuantity Needed Taken Cost per day Cost per week Cost per month
Current Treatments
Ribavirin 11 mg/kg 946 mg $10 per 200 mg capsule 5 Daily $50 $350 $1,525
PEG-IFN α 180 µg 180 µg $600 per 120 µg kit 1 Weekly $600 $2,700
PEG-IFN α 1.5 µg/kg 129 µg $600 per 120 µg kit 1.075 Weekly $645 $2,903
Total Cost $950 $4,225
SCH 503034/Boceprevir
Break even in 10 years $ 20.23 per 200 mg capsule 1 Daily $ 20.23 $ 141.64 $ 617.17
Break even in 9 years $ 21.02 per 200 mg capsule 1 Daily $ 21.02 $ 147.13 $ 641.07
Break even in 8 years $ 22.00 per 200 mg capsule 1 Daily $ 22.00 $ 153.99 $ 670.95
Break even in 7 years $ 23.26 per 200 mg capsule 1 Daily $ 23.26 $ 162.80 $ 709.36
Break even in 6 years $ 24.94 per 200 mg capsule 1 Daily $ 24.94 $ 174.56 $ 760.58
Break even in 5 years $ 27.29 per 200 mg capsule 1 Daily $ 27.29 $ 191.02 $ 832.28
Break even in 4 years $ 30.81 per 200 mg capsule 1 Daily $ 30.81 $ 215.70 $ 939.84
Break even in 3 years $ 36.69 per 200 mg capsule 1 Daily $ 36.69 $ 256.84 $ 1,119.11
Break even in 2 years $ 48.45 per 200 mg capsule 1 Daily $ 48.45 $ 339.13 $ 1,477.63
Break even in 1 year $ 83.71 per 200 mg capsule 1 Daily $ 83.71 $ 585.98 $ 2,553.22
Results
Development and Manufacturing will take approximately 14 years
The most likely total cost from research and development through plant construction will cost $528 million
This is less than the average cost for development of a drug, $802 million, as reported in the Journal of Health Economics
This cost is expensive, but relative to other drugs the cost of research and commercialization for boceprevir is reasonable
1 month of current treatments: $4,2251 month of boceprevir: $2553 with 1 year payback
Predict new molecule that will work better than Boceprevir
Selecting Molecules
Selection CriteriaCompare to Boceprevir
Ki
Inhibition constant: [L] at which ½ of the sites are occupiedSelectivity against human neutrophil elastase (HNE)
Ki (HNE)/ Ki (HCV)Pharmacokinetics
Bioavailability: Fraction that reaches systemic circulation (4-11%)
AUC: Area under the concentration time curve (0.12 uMh )
Solution Procedure
Proposed Molecules
NS3/NS4A Complex
Binding of Drug to Protease
Docking Server Ligands
Docking Server ResultsLigand
Inhibition Constant Ki
(mM)
Catalytic Triad Amino Acids
boundBoceprevir 0.56 3
#1 10.83 2#2 50.92 2#3 0.85 2#4 155.17 2#5 0.24 2#6 48.63 2#7 0.24 2#8 0.09 2#9 0.04 2
#10 0.32 2#11 2.19 3#12 3.14 2#13 1.34 2#14 1.26 3#15 0.33 3#16 5.05 2
Results16 potential drugs have been developedAll bind to catalytic triad
Potential drug #9Lower KiHigher HNE/HCV
We recommend that potential drug #9 be further evaluated using different docking software, and then be synthesized and undergo animal trialsWe also recommend that further research continue on potential drugs 5, 7, 8, 10 and 15
Increase selectivityKeep high binding affinity
Questions?
Docking Server
molecular modeling internet service
developed by Virtua Drug Ltd
capable of calculating the site, geometry, and energy of molecules interacting with proteins
Genetic algorithms
Genotype - translation, orientation, and conformation
Phenotype - atomic coordinates of the ligand
Fitness - total interaction energy of the ligand with the protein
Genetic algorithms
Individuals that have low fitness die New individuals are created by inheriting genes from either of two parents Mutations also occur randomly
DockingServer can predict where and how a ligand will bind to be most energetically favorable
Lamarckian genetic algorithm
even more efficient
uses desirable phenotypes to produce desirable genotypes
Synthesis of Boceprevir
FCI
Direct CostsEquipment CostsEquipment InstallationInstrumentation and ControlsPipingElectrical SystemsBuildingsInsulationYard ImprovementsService Facilities
Indirect CostsConstruction ExpensesLegal ExpensesContractor’s feeContingency
Questions?