Manoj Kumar ChhikaraMVSc, PhDAssociate Director, R&D

How promising is the development of a

semi-synthetic meningococcal conjugate vaccine ?- a case study

5th Asia Pacific Global Summit and Expo on Vaccines & Vaccination

29th July 2015

Contents

• Need for an affordable multivalent meningococcal conjugate

vaccine

• Challenges and avenues in conjugate vaccine manufacture

• Promises from synthetic vaccine technologies for conjugate

vaccines

• Semi-synthetic conjugate vaccine research at Hilleman Labs

• Conclusions

Need for an affordable multivalent meningococcal conjugate vaccine

MeningitisInflammation of meninges

Can be bacterial, viral, sometimes fungal

Bacterial meningitis: Meningitis and /or Septicaemia

Causes: N. meningitidis, Str. pneumoniae, H. influenzae, E. coli, GBS, GASL. monocytogenes and several others

Symptoms: Fever, vomiting, rashes, headache, delirium, stiffness, drowsiness, muscle and/or joint pain

Meningococcal Epidemics

N. meningitidis epidemics: • 1996 epidemic: Africa; 20,000 reported deaths

https://www.nathnac.org/pro/factsheets/documents/meningitis.pdf

• In 2000 and 2001 several hundred pilgrims attending the Hajj in Saudi Arabia were infected with N. meningitidis W. Then in 2002, W emerged in Burkina Faso, striking 13,000 people and killing 1,500. http://www.cdc.gov/meningococcal/global.html

• 2007 epidemic: Burkina Faso; 22,255 suspected cases, 1490 deaths https://www.nathnac.org/pro/factsheets/documents/meningitis.pdf

• 2009 epidemic: 14 countries from African meningitis belt 88,199 suspected

meningitis cases, 5352 deaths. (http://www.who.int/mediacentre/factsheets)

• 2014 epidemic season: 19 African countries; 11 908 suspected cases including 1146 deaths, lowest numbers since 2004 http://www.who.int/mediacentre/factsheets/fs141/en/

• Up to 20% mortality in epidemics and serious disability after survival in several cases

Major Meningococcal serogroups by geography: A, B and C account for 90% of IMD worldwide

B,C,Y

B,CY

B,CW

B,C

A,C,W,X

A,B,CY,W

A,C

A,C

A

B,C

Source :Jafri et al. Population Health Metrics 2013, 11:17

https://www.gov.uk/government/publications/meningococcal-disease-laboratory-confirmed-cases-in-england-and-wales

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/437901/150622_ACWY_bipartite_letter.pdf

The solution is: multivalent meningococcal conjugate vaccine

Opportunities in development of cost effective conjugate vaccines • Existing poly-valent meningitis vaccines are effective but are

too expensive to be marketed in developing countries.

• Need to provide the right serogroup combination to provideprotection for the specific needs of the countries/regions

• Need to reduce dependency on one or few low cost vaccinesuppliers

• The existing cost of conjugate vaccines can be reduced byadapting to novel technologies and thermo-stabilization.

GAVI Alliance: Strategic Demand Forecast as of Second Quarter 2014

Based on increasing prevalence of other serogroups the need for cost effective multivalent meningococcal conjugate vaccine is warranted

Challenges & avenues in multivalent conjugate vaccine manufacture

in year 2011

http://www.meningitisinfo.com/Epidemiology_ssi.aspx

13 serogroups, regional variations

Seroprevalence varying by age groups and time

All ages Infants <1yr

Different time intervals

http://www.meningitisinfo.com/Epidemiology_ssi.aspxCONFIDENTIAL © HILLEMAN LABORATORIES

Complex processes & analytics

PolysaccharideActivated

saccharide

Carrier protein

Bulk Conjugate

1. Identity2. Molecular Size3. Composition4. Protein impurity5. Nucleic acid impurity6. Endotoxin7. Moisture content

1. Number of functional groups2. Mol. Size distribution

1. Identity2. Mol. Size distribution3. Saccharide content4. Protein content 5. Saccharide:protein ratio6. Endotoxin7. Conjugation markers8. Residual reagents9. Sterility

1. Identity2. Purity3. Extent of derivatization4. Endotoxin5. Specific toxicity

1. Identity2. Saccharide content3. Residual moisture (if lyophilized)4. Adjuvant content (if used)5. Preservative content (if used)6. Pyrogen content7. General safety test8. pH9. Sterility10. Physical inspection

CO

NJU

GA

TE

VA

CC

INE

Activation

Conjugation Formulation

1. Novel/improved polysaccharide production processes2. Antigen Synthesis

a. Organic synthesisb. Enzymatic synthesis

3. Reverse engineering (Broader coverage)4. Novel/improved conjugation processes

a. Reductive aminationb. Cyanylationc. Oxime chemistryd. Thio-ether conjugation etc.

5. Novel formulations5. Novel Analytics

a. Sophisticated physico-chemical analysesb. Multiplexed immunoassays (xMAP, MSD etc.)

Novel Technology solutions to Conjugate vaccine development

Developments in semi-syntheticconjugate vaccine R&D

How interest in semi-synthetic conjugate vaccines started ?

The initial success…with Hib

Research in developing semi-synthetic conjugate vaccines Cryptococcus neoformans: Vaccine (2005), 3961 Clostridium difficile: Chem. Biol. (2011); J. Am. Chem. Soc. (2013) Group A Streptococcus: Bioorg. Med. Chem. Lett. (2013) Vibrio cholerae: Glycoconj. J. (2013) Neisseria meningitidis group W: Ange. Chemie. Int. Ed. (2013) Streptococcus pneumoniae type 14: Russian Chem. Bull. (2014) Bacillus anthracis: Curr. Org. Chem. (2014) Shigella: Chemi. Commn. (2015) Neisseria meningitidis group X: Archivoc (2013); Baielstein J.Org. Chem.

(2014); RSC Adv. (2015)

Why there is no second semi-synthetic vaccine yet?

Questions in front of a manufacturer before adapting a novel technology

Ease of modifying structure ? ?Loss of epitopes during

conjugation? ?

Conjugation yield ? ?

Parameter Conventional technology

Novel technology

GMP requirements ? ?Duration for production ? ?Cost of production ? ?Batch to batch consistency ? ?Host cell impurities (e.g.

Protein/nucleic acid)? ?

Endotoxin content ? ?Residuals ? ?Analytics ? ?Stability ? ?Immunogenicity ? ?

Mening Conjugate Vaccine Program at Hilleman Labs

MeningACWXY

Conventional conjugates (Bacterial

PS and carrier protein)

Semi-synthetic conjugates (Synthetic

PS and bacterial carrier protein)

Options for development

Regional vaccine(s)

Pentavalent ACYWX vaccine

Tech

nolo

gy

Vale

ncy

R&D AT HILLEMAN LABSPolysaccharide production VERSUS Oligosaccharide synthesis

O

COOH

O

HOAcHN

O OHHO

O

COOH

HOAcHN

OHOHO

COOH

HOAcHN

HO OHHO

OO

COOH

HOAcHN

OHOH

O NH2

O COOMeS

OHN

ClH2COCO OClH2COCO

O

O

COOMe

OHN

HO OHOH

O

ON3

O Cl

+

O

COOMe

O

OHN

ClH2COCO OClH2COCO

O

COOMe

O

OHN

OAcOAc

O O

N3

O Cl

O COOH

OH

HOAcHN

HO OHOH

Initiation unit with linkerPropagation unit

Retro-synthesis of Mening C Tetramer

Cell Banking • Extensive characterization

Fermentation• Handling

pathogenic organisms

PS purification

• Several steps

Size reduction

Bacterial Polysaccharide production

• Physical, Chemical

Significant difference in GMP requirements and raw material required for the two options

Oligomers synthesized at Hilleman Labs

OHO

OAcHN

HOOH

P

O

OO OHO

OAcHN

OH

P

O

OO O

HO

OAcHN

OH

P

O

OO OHO

OAcHN

OH

5 NH2

Na

Na

Na

Mening C tetramer and octamer

Mening X tetramer

Mening W tetramer

Mening Y tetramer

Highly defined oligomers

0 .40 .60 .81 .01 .21 .41 .61 .82 .02 .22 .42 .62 .83 .03 .23 .43 .63 .84 .04 .24 .44 .64 .85 .05 .25 .45 .65 .86 .06 .2f1 (ppm )

-5000

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

4.3

2

3. 9

7

11. 3

7

2. 0

5

3. 2

9

26. 0

5

1. 0

8

3. 0

0

1. 2

0

1. 3

9

1. 4

8

1. 9

0

2. 8

1

3. 3

8

3. 5

8

3. 6

9

3. 7

8

3. 8

6

4. 7

0

5. 3

6

1H-NMR 13C-NMR

2030405060708090100110120130140150160170180f1 (ppm )

-5000

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

65000

24. 3

8

27.2

2

27. 8

9

29. 3

2

30.7

4

41. 6

5

55.7

2

57. 8

2

58. 0

4

62. 2

3

62. 5

0

62.7

4

71. 8

5

72. 5

3

72. 9

9

74. 6

6

75. 3

1

76. 5

0

77. 1

8

96. 1

8

96. 5

7

96. 8

9

96. 9

3

97. 0

8

103

. 65

132

. 15

162

. 76

177

. 03

DEPT 2D HSQC 2D COSY

HPSEC

Additional testing: MS; IR; TLC

Advantages in size distribution

MenC PS lots analyzed using PWXL 4000-5000 columns in series (RI signal)

MenC tetramer lots analyzed using PWXL 3000 column (RI signal)

Different Conjugation Methods affect the polysaccharide epitopes

Periodate oxidation of Hib-PRP

Reductive amination of Str. pneumoniae Serotype 19F Polysaccharide

Cyanylation of 19F-PS using CDAPClin Vaccine Immunol 2011 18(2): 327-336

Clin Vaccine Immunol 2011 18(2): 327-336

Synthetic oligosaccharides can be conjugated without impacting OS epitopes with high yields

HN

Freshly prepared Protein-maleimideO

N

O

O

HN

O

SHPolysaccharide

HN

O

N

O

O

NH

O

SPolysaccharide

Crude Conjugate

Mix Protein to PS in 1:30 molar ratio

Overnight mixing at 4°C

Purif ication using 10 kd Amikon Ultra f ilter.

Oligosaccharide & Protein mix is in PBS at ph 6.8.

Same chemistry for all oligosaccharides

Consistent, Repeatable process with high yields

MenC-PS & Conjugate MenC-Tetramer & Conjugate

Sharp contrast in OS and conjugate

profile and minimum

heterogeneity

Conjugate Lot No. OS:Pr Ratio Free OS % Conjugation yieldMenCTM-TT-1 0.25 2.5 21%MenCTM-TT-2 0.25 1.2 32%MenCTM-TT-3 0.24 3.0 38%MenCTM-TT-4 0.28 <1 47%MenCTM-TT-5 0.23 1.5 38%MenCTM-TT-6 0.28 5.9 39%MenCTM-TT-7 0.25 9.9 35%MenCTM-TT-8 0.26 <1 27%

MenC Octamer-TT conjugates are immunogenic and non-inferior to licensed vaccine

IgG GMC SBA titre

MenC Tetramer-TT & Octamer –TT conjugates show comparable immunogencity

IgG GMC SBA titre

CONFIDENTIAL © HILLEMAN LABORATORIES

MenX-TT Conjugate give rise to high IgG concentration in mice

INFERENCE: 1µg of conjugated MenX-tetramer-TT gives 10-15 fold higher response than vehicle control

Anti-MenX IgG GMC Post dose-3 Study 1-3

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

EU/m

l

Negative control 195 283 672 672 672

Men XTm 1mcg 3512 4287 7235 8843 8786

Study 1 β Tm

Study 2 β Tm

Study 3 β Tm

Study 3 α Tm

Study 3 α Tm

SBA data awaited

Efforts towards automation… Automated synthesis of oligosaccharides as a basis for drug discoveryPeter H. Seeberger & Daniel B. WerzNature Reviews Drug Discovery 4, 751-763 (September 2005)

Automation reduces significant time for organic synthesis

Comparative analysis

Duration for production +++ - Significantly longer time for synthesis, (Scope for Automation)

Parameter Bacterial PS Synthetic OS RemarksGMP requirements - +

Ease of modifying structure - ++Loss of epitopes during

conjugation- ++

Batch to batch consistency - ++ PS from live organisms vs chemical synthesis

Protein/nucleic acid impurities

- ++

Endotoxin content - ++Residuals + + Still under evaluation

Conjugation yield - +

Stability - + Multiple vs Single link and Long vs small repeats

Analytics - + Highly defined oligomers Immunogenicity + +

Cost of production + + Still under evaluation

+ : a positive attribute of the technology - : a negative attribute

1. Among all the other novel technologies, synthetic approaches to develop new conjugate vaccines is an emerging subject

2. Initial successes have paved the way for exploration of synthetic platform technology for other vaccine candidates

3. The advantages of synthetic approach over the conventional approaches have upper hand as compared to the possible short falls

4. The approach may lead to successful candidates which are difficult to be produced by conventional approaches

Conclusions

Acknowledgements

• Dr. Davinder Gill, CEO, Hilleman Labs• Dr. Zimra Israel, VP and Head, R&D, Hilleman Labs• Conjugate Vaccine Program(CVP) teams at Hilleman Labs

• Sandeep Sharma; Nitin Kumar, Sarmad Hanif• Rakesh Rana, Juned Dalal, Deepti Singh• Kishore Harale, Neelesh, Jeetendra• Lab technicians and support staff

• Consultants for CVP at Hilleman Labs• CROs (animal studies, analytics, organic synthesis)