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Vaccine Development Pathway

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Vaccine Development Pathway Prof RN Basu • What is a Vaccine? • Vaccines are protective treatments that prevent disease by training the body’s immune system to recognise and respond to infectious pathogens such as bacteria, viruses and parasites to stop you getting sick. • This protection can be short-lived or life-long, depending on the type of vaccine and the disease. • Some vaccines contain weakened (attenuated) or inactivated versions of infectious agents, particularly viruses. • Others contain molecules that mimic specific components of pathogens or toxins produced by bacterial infections. 2 3 Name Vaccine Type Primary developer Country of origin Authorisation/Appr oval BNT162b2 mRNA based vaccine Pfizer, BioNTech;Fosun Multinational UK, Bahrain, Pharma Canada, Mexico, US CoronaVac Inactivated vaccine (formalin Sinovac China China with alum adjuvant) Sputnik V Non-replicating viral vector Gamaleya Research Russia Russia Institute, Acellna Contract Drug Research and development BBIBP-CorV Inactivated Vaccine BeijingInstitute China China ofBiologicalProducts;Chi na National Phtil 4 Name Vaccine Type Primary developer Country of origin Authorisation/Appr oval No Name Inactivated vaccine Wuhan Institute of China China announced Biological Products; China National Pharmaceutical Group (Sinopharm) EpiVac Corona Peptide vaccine Federal Budgetary Russia Russia Research Institution State Research Centre of Virology and Biotechnology 5 Candidate Mechanism Sponsor Trial Phase Institution V591 Measles vector vaccine University of Pittsburgh’s Phase I University Centre for Vaccine ofPittsburgh;Themis Research Biosciences;Institut Pasteur VXA-CoV2-1 Recombinant vaccine Vaxart Phase 1 Vaxart (adenovirus type 5 vector AAVCOVID Gene-based vaccine Massachusetts Eye and Preclinical Ear; Massachusetts General Hospital;University of Pennsylvania AdCOVID Intranasal vaccine Altimmune preclinical University of Alabama at Birmingham 6 Candidate Mechanism Sponsor Trial Phase Institution ChAd—SARS- Adenovirus-based vaccine Washington University Pre-clinical WashingtonUniversi CoV-2-5 School of Medicine in ty Schoolof St.Louse Medicine in St.LouisHalo HaloVax Self-assembling vaccine VoltronTherapeutics,Inc.; Pre-clinical MGH Vaccine HothTherapeutics,Inc. andImmunotherapy Center HDT-301 RNA vaccine University Pre-clinical ofWashington;NationalIn stitutes ofHealth RockyMountainLaborator ies;HDT Bio Corp LinealDNA DNA Vaccine Takis Biotech Pre-clinical Pre-clinical 7 Candidate Mechanism Sponsor Trial Phase Institution HDT-301 RNA vaccine University Pre-clinical ofWashington;NationalIn stitutes ofHealth RockyMountainLaborator ies;HDT Bio Corp MRT5500 Recombinant Sanofi, Translate Bio Pre-clinical vaccine No name lii-Key Generex Biotechnology Generex announce peptideCOVID- d 19vaccine 8 Name Vaccine Type Primary developer Country of origin Authorisation/Appr oval BNT162b2 mRNA based vaccine Pfizer, BioNTech;Fosun Multinational UK, Bahrain, Pharma Canada, Mexico, US CoronaVac Inactivated vaccine (formalin Sinovac China China with alum adjuvant) Sputnik V Non-replicating viral vector Gamaleya Research Russia Russia Institute, Acellna Contract Drug Research and development BBIBP-CorV Inactivated Vaccine BeijingInstitute China China ofBiologicalProducts;Chi na National Phtil 9 10 • Man always wanted to protect themselves from the scourge of disease • In this quest man was looking for the means to prevent disease • Thus concept of vaccine was born • King Mithridates (132 to 63 BC) VI of Pontus (Black Sea Region) immunised himself against fungal toxin by administering small non- toxin amounts • He wanted to protect himself from assassination attempts by poisoned food • He is considered as the first individual who applied the principle of immunology1 11 • In 1721, Dr Zabdiel Boylston variolated 240 people in Boston under persuasion by an evangelist minister, Cotton Mather2 • All excepting six survived i.e., the mortality from the procedure was 2.5% only • At that time more than 30% people died annually from naturally acquired small pox • This led to wide acceptance of variolation in Boston in 18th century • The vaccine era was actually began in 1774 when a farmer named Benjamin Jesty observed that milkmaids who had had cowpox did not get small pox 12 • This was about 22 years before Edward Jenner’s first inoculation and publication in 1798 • Sometime in 19th century vaccinia virus (a mouse pox virus) replaced cowpox in the vaccine • Many lessons were learnt from the small pox vaccine • Initially, small pox pus was used from one person to another and so on but syphilis was also passed along with • Loss of vaccine potency occurred after serial human passages • Many different types of animals were used for vaccine preparation • Ultimately by and large cattle were utilised for vaccine 13 • Subsequent work was done by Pasteur during the 19th century • It refined and consolidated the basis of vaccinology • The process involved the principles of isolation, inactivation, and administration of key components from disease-causing pathogens. 14 • Some concepts were developed • These were: • Attenuation (weakening the capacity to produce disease) of bacteria and viruses • Killed or inactivated (normally by chemicals such as formalin) vaccine • Live attenuated vaccine • Late in 19th century and early 20th century serum and cellular immunity were recognised • This gave rise to the concepts of active (body actively produces) and passive (immune serum from other human and animal was injected) immunity 15 • In Diphtheria and tetanus toxins were recognised as the cause of these diseases • Antiserum was made in horses (antitoxin) that could neutralise toxin effects of these diseases • Antitoxin was first used to prevent diphtheria in a child in 1891 • Early vaccines against diphtheria and tetanus were developed at the beginning of the 20th century • These vaccines combined toxin with antitoxin • In the second half of 20th century many vaccines were developed that could prevent many childhood diseases 16 • It was demonstrated that the strategy of ring immunization for small pox was a success story for eradication of small pox in 1980 • The last case of small pox had occurred 4 years earlier • Ring immunization means: identification, immunization of all contacts of cases and the contacts of contacts • Some countries like USA and Russia still holds the virus as the WHO repository laboratories • But there is a concern that some other countries could be holding surreptitiously stocks of the virus • These countries could possibly use the virus as a biological weapon 17 • Because of the concern of bioterrorism, the US government started a programme in 2001 for development of small pox vaccine • These vaccines were to be developed using modern techniques • This technique involved: • Development of a new plaque purified seed virus • Cultivated in tissue culture, and • Development and testing of a safer human replication deficient strain of virus • This was termed as “modified vaccine Ankara” 18 • Vaccine • The term vaccine is derived fro the word, vacca • This is a Latin word meaning cow • Because cowpox pus was used in prevention of small pox • Vaccination • It is a procedure deliberately undertaken for preventing an infectious diseases by sensitizing the body’s immune system to deploy its acquired defences against that infectious agent • Some vaccines are used to enhance existing immune system – therapeutic vaccination 19 • Vaccines developed by trial and error • Small pox vaccine was developed because of direct observation • First variolation of used for vaccination • Sometimes there was fatal outcome in this procedure • But this was of lower risk than when small pox was acquired in an epidemic • It was later recognised that cowpox could provide immunity against small pox • The vaccines for tetanus, diphtheria and pertussis were prepared by trial and error • These were successful experimentation but some other trial failed and sometimes the consequences were quite adverse 20 • Diphtheria • Causative organism for this disease is Corynerbacterium diphtheriae • It produces toxins that cause cell death at the site as well as elsewhere in the body • The toxin causes many effects that ultimately cause death • Serum from horses immunised with diphtheria toxin was used for immunising and treating diphtheria • In early experiments production was not supervised and controlled causing deaths • This prompted enactment of Biologics Control Act of 1902 in USA • In India, CDSCO controls the biologics 21 • Active immunization using diphtheria toxin was effective • But it cased many adverse events • In early 1920, it was shown that toxins treated with heat and formalin lost its potency but still was immunogenic • Diphtheria toxoid was evolved since then • Vaccination with diphtheria toxoid was highly effective to prevent the disease • A fully immunised person very rarely can become infected as a carrier or may suffer from mild disease • But if a person is not fully immunised, the risk of becoming severely ill after exposure is 30 times higher page 22 Vaccine Development Pathway 23 • Introduction3 • Vaccines represent a relatively small proportion of the entire pharmaceutical industry • Several new vaccines have achieved an enormous success • In the US alone, the annual sales exceeded $500 million • The timeline for development of a vaccine and its approval from the regulatory authorities is long and may be 15 years or more • Moreover, it needs a considerable amount of investment 24 • To get approval from regulatory authorities,
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