Friday 11 December 2020

Coronavirus (31) mRNA vaccine candidate for COVID-19: BNT162b2 (part a)

Coronavirus (31) mRNA vaccine candidate for COVID-19: BNT162b2 (part a)
Continued from my last blog post.
1. BNT162b2 by Pfizer Inc. and BioNTech SE
BNT162b2 was the first COVID-19 vaccine in the world to achieve authorization. The UK regulator, Medicine and Healthcare products Regulatory Agency (MHRA), authorized emergency supply of COVID-19 mRNA vaccine under Regulation 174 on 2nd December.1 And today, the U.S. Food and Drug Administration (FDA) also granted an Emergency Use Authorization (EUA) to permit the emergency use of the vaccine in individuals that are 16 years old and over.2

The UK has ordered 40 million doses of the vaccine, which is enough to vaccinate 20 million people. The first batch of the mRNA vaccine arrived in the UK on 3rd December from Belgium. By the end of this year, the UK government expects to have 800,000 vaccine doses arrived. The vaccination started on 8th December. According to a suggestion from the Joint Committee on Vaccination and Immunisation (JCVI), the first batch should be given to NHS hospital staff and patients. Care home residents and care home staff are prioritised for vaccination next.3

The vaccination of BNT162b2 is a two-dose regimen, 21 days apart, and administered intramuscularly (injected into a muscle). The vaccine comes in concentrated form and remains stable for 6 months at -80°C to -60°C. Once a vaccine vial is taken out from the freezer and thawed, it will be diluted with sodium chloride 9 mg/mL (0.9%) solution. The diluted, ready to use vaccine should be stored between 2°C and 25°C and used within 6 hours after dilution. Before injection, you can have a look with the nurse to check if the vaccine appears as an off-white solution with no particulates visible. The vaccine cannot be used if particulates or discolouration are present.4

You should bear in mind that the protection is not fully effective until at least 7 days after the second dose of the vaccine. Even you are vaccinated, the 94%-95% of efficacy of the vaccine BNT162b2 means that you are not entirely safe from COVID-19. Vaccination with the mRNA vaccine may not protect all recipients.4-6

It is important to note that the following peoples are not suitable to be vaccinated with BNT162b2:4
1. Children under 16 years of age. The safety and efficacy of the vaccine in this age group has not yet been established;
2. Pregnant women. Animal reproductive toxicity studies have not been completed. The vaccine, therefore, is not recommended during pregnancy;
3. Women during breast-feeding. It is unknown whether the mRNA vaccine is excreted in human milk. There may be a risk to newborns and infants;
4. Individuals receiving anti-coagulant therapy, and ones with bleeding disorder. Anti-coagulant therapy and bleeding disorder would contraindicate an intramuscular injection;
5. People with a history of significant allergic reactions. There were reports of allergic reaction shortly after the injection in two NHS workers who have a history of serious allergies and carry adrenaline pens around with them.7 MHRA advised that people with a history of significant allergic reactions should not have the mRNA vaccination.4

Moreover, it should be bourne in mind that if you are of childbearing age, you should avoid pregnancy for at least 2 months after the second shot. And if you are currently suffering from acute severe febrile illness, the administration of the mRNA vaccine should be postponed.4

The development of BNT162b2
The vaccine was first developed by BioNTech. Pfizer later joined (in March) to accelerate the development programme, which initially included 4 vaccine candidates. Three vaccine candidates represent a different combination of mRNA format, either a uridine containing mRNA or nucleoside modified mRNA, and target antigen: either the larger spike sequence of SARS-CoV-2 or the smaller optimized receptor binding domain (RBD) from the spike protein. The fourth vaccine candidate contains self-amplifying mRNA. Each mRNA format is combined with a lipid-nanoparticle (LNP) formulation.8,9

The pre-clinical studies on the four mRNA vaccine candidates was completed in Germany in April.9 Two vaccine candidates, BNT162b1 and BNT162b2, induced high viral antigen specific CD4+ and CD8+T cell responses, and high levels of neutralizing antibody in various animal species. They offered protective effects in Rhesus macaques from SARS-CoV-2 infection. The study result on the vaccine candidate BNT162b2 was available to the public in September.10

The first clinical trial of the vaccine candidates started on 23rd April in Germany (NCT04380701; EudraCT: 2020-001038-36) and later in the US (NCT04368728; C4591001).11 The initial clinical trial included dose range studies, aiming to determine the optimal dose for the mRNA vaccine candidates, as well as to evaluate the safety and immunogenicity of the vaccines. Pfizer took care of clinical trials in the US and other countries other than Germany, while BioNTech conducted its own trials in Germany.

Among the four mRNA vaccine candidates, BNT162b1, a lipid-nanoparticle (LNP)-formulated nucleoside-modified mRNA that encodes the SARS-CoV-2 receptor binding domain (RBD) from the spike protein, and BNT162b2, a LNP-formulated nucleoside-modified mRNA that encodes the spike glycoprotein of SARS-CoV-2, were chosen to be evaluated in the phase 1/2 clincial trials. Both vaccine candidates demonstrated a manageable tolerability at dose levels that elicited robust immune responses. However, BNT162b2 was found to have a milder reactogenicity profile. Based on the preclinical and clinical data obtained in phase 1/2 studies, BNT162b2 was chosen to enter into phase 2/3 study at a 30µg dose level in a 2 dose regimen.12-14

The information published in November shows that BNT162b2 is now in phase 3 clinical trials in the US, Germany, Argentina, Brazil, South Africa, and Turkey. A pharmaceutical company from China, Fosun Pharma, jointly conducted phase 2 clinical trials in Jiangsu, China with BioNTech in November.15

Safety results
The safety of BNT162b2 was evaluated in participants 16 years of age and older in two clinical studies. Study EudraCT: 2020-001038-36 enrolled 60 participants in Germany aged between 18 and 55. Study C4591001 enrolled approximately 44,000 participants of aged 12 or older, in the US, Turkey, South Africa, and South America.

In a group of age 16 and above in Study C4591001, a total of 21,720 participants received at least one dose of BNT162b, and 21,728 participants received a placebo. Out of these, at the time of the analysis, 19,067 participants (9531 who received BNT162b2 and 9536 who received the placebo) were evaluated for safety, two months after the second dose. The first interim report of the phase 3 study was published in November.5,6

The most frequent adverse reactions in participants aged 16 years and older were pain at the injection site (>80%), fatigue (>60%), headache (>50%), myalgia (>30%), chills (>30%), arthralgia (>20%) and pyrexia (>10%). The reactions were usually mild or moderate in intensity and resolved within a few days after vaccination.4

There was no pause of study in the clinical trials for the mRNA vaccine BNT162b2, and no report of hospitalization or death after the vaccination in the clinical trials.

Pre-order agreement
Since the mRNA vaccine candidates entered the clinical trial, Pfizer and BioNTech have signed supply agreements with different countries to deliver millions of doses of the vaccine if approved. The companies signed agreements in July to deliver up to 600 million doses of their vaccine for COVID-19 to the US (enough for 2 per person for nearly the whole population), and 120 million doses to Japan.16,17 In August, the companies signed agreements to provide the mRNA vaccine to Canada.18 The European Union also signed a contract in November with the two companies to provide the EU with 200 million doses of the mRNA-based vaccine.19 Today, BioNTech announced an agreement to supply Mainland China with an initial 100 million doses of their mRNA-based vaccine candidate.15 According to the press release from Pfizer, they have the goal of manufacturing globally up to 50 million doses by the end of 2020 and approximately 1.3 billion doses by the end of 2021.6

BioNTech received an up-front payment of $185 million, including an equity investment of approximately $113 million, from Pfizer, upon the collaboration to develop an mRNA vaccine with BioNTech. The company will be eligible to receive further payments of up to $563 million for a potential total consideration of $748 million.8



References
1. Decision: Regulatory approval of Pfizer/BioNTech vaccine for COVID-19. Gov.UK news release, 2nd Dec., 2020. https://www.gov.uk/government/publications/regulatory-approval-of-pfizer-biontech-vaccine-for-covid-19
2. FDA takes key action in fight against COVID-19 by issuing emergency use authorization for first COVID-19 vaccine. FDA news release, 11th Dec., 2020. https://www.fda.gov/news-events/press-announcements/fda-takes-key-action-fight-against-covid-19-issuing-emergency-use-authorization-first-covid-19
3. Covid-19: UK 'confident' of having 800,000 vaccine doses by next week. BBC news, 6th Dec., 2020. https://www.bbc.co.uk/news/uk-55184849
4. Information for healthcare professionals on Pfizer/BioNTech COVID-19 vaccine. MHRA website, 10th Dec., 2020. https://www.gov.uk/government/publications/regulatory-approval-of-pfizer-biontech-vaccine-for-covid-19/information-for-healthcare-professionals-on-pfizerbiontech-covid-19-vaccine
5. Pfizer and BioNTech announce vaccine candidate against COVID-19 achieved success in first interim analysis from phase 3 study. Pfizer press release, 9th Nov., 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-vaccine-candidate-against
6. Pfizer and BioNTech conclude phase 3 study of COVID-19 vaccine candidate, meeting all primary efficacy endpoints. Pfizer press release, 18th Nov., 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine
7. Covid-19 vaccine: Allergy warning over new jab. By Nick Triggle and Rachel Schraer. BBC News, 9th Nov., 2020. https://www.bbc.co.uk/news/health-55244122
8. Pfizer and BioNTech to co-develop potential COVID-19 vaccine. Pfizer press release, 17th March, 2020. https://www.pfizer.co.uk/pfizer-and-biontech-co-develop-potential-covid-19-vaccine/
9. BioNTech and Pfizer announce regulatory approval from German authority Paul-Ehrlich-Institut to commence first clinical trial of COVID-19 vaccine candidates. Pfizer press release, 22nd April, 2020. https://www.pfizer.com/news/press-release/press-release-detail/biontech_and_pfizer_announce_regulatory_approval_from_german_authority_paul_ehrlich_institut_to_commence_first_clinical_trial_of_covid_19_vaccine_candidates
10. A.B. Vogel, I. Kanevsky, Y. Che, et al. A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates. BioRxiv, Sept. 08, 2020. doi: https://doi.org/10.1101/2020.09.08.280818
11. BioNTech and Pfizer announce completion of dosing for first cohort of phase 1/2 trial of COVID-19 vaccine candidates in Germany. Pfizer press release, 29th April, 2020. https://www.pfizer.com/news/press-release/press-release-detail/biontech-and-pfizer-announce-completion-dosing-first-cohort
12. U. Sahin, A. Muik, E. Derhovanessian, et al. COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses. Nature, 2020;586, 594–599.
13. E.E. Walsh, R.W. Frenck, A.R. Falsey, et al. Safety and immunogenicity of two RNA-based Covid-19 vaccine candidates. N. Engl. J. Med., 2020 Dec 17;383(25):2439-2450. doi: 10.1056/NEJMoa2027906. Epub 2020 Oct 14.
14. Pfizer and BioNTech choose lead mRNA vaccine candidate against COVID-19 and commence pivotal phase 2/3 global study. Pfizer press release, 27th July, 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-choose-lead-mrna-vaccine-candidate-0
15. BioNTech and Fosun Pharma to supply China with mRNA-based COVID-19 vaccine. BioNTech press release, 16th Dec., 2020. https://investors.biontech.de/news-releases/news-release-details/biontech-and-fosun-pharma-receive-approval-commence-covid-19/
16. Pfizer and BioNTech announce an agreement with U.S. Government for up to 600 million doses of mRNA-based vaccine candidate against SARS-CoV-2. Pfizer press release, 22nd July, 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-agreement-us-government-600
17. Pfizer and BioNTech to supply Japan with 120 million doses of their BNT162 mRNA-based vaccine candidate. Pfizer press release, 31st July, 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-supply-japan-120-million-doses-their
18. Pfizer and BioNTech to supply Canada with their BNT162 mRNA-based vaccine candidate. Pfizer press release, 5th August, 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-supply-canada-their-bnt162-mrna-based
19. Pfizer and BioNTech reach an agreement to supply the EU with 200 million doses of their BNT162b2 mRNA-based vaccine candidate against SARS-CoV-2. Pfizer press release, 11th Nov., 2020. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-reach-agreement-supply-eu-200-million


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