July 8, 2020
By Reza Yacoob and Noel Courage
Reza Yacoob is the former Senior Director, Intellectual Property Canada, at Sanofi Pasteur.
Many technologies are involved in the push to produce a viable SARS-Cov 2 vaccine (click here for Part I of our article). Part II of our article will review the pathway to vaccine approval and the current landscape of candidate vaccines.
Once a potential vaccine formulation is in hand, it has to be proven safe and effective. This requires solid scientific evidence, which takes time to produce through the government vaccine regulatory process. Typical and accelerated regulatory processes are illustrated in the figure at the end of this article. The first stage is pre-clinical work, testing the basic safety and toxicity of the formulation in lab tests using chemical assays and cell tests. Patent applications may be filed at this stage, with a typical goal to have patents issued prior to product launch.
If a formulation makes it through the preclinical stage, then it goes into the clinical trial process. Clinical development studies assess the effects of vaccines on patients for safety, immunogenicity, and efficacy. The studies are generally done through a staged process involving: phase 1, early safety and immunogenicity in small numbers 5-10 healthy individuals; phase 2, safety, dose ranging, and immunogenicity in 200 to 400 individuals; and phase 3, safety and efficacy trials in the target population at a licensure standard. These types of studies would have to be compressed for COVID-19 with creative study designs to reduce the timelines to approval. For example, a Phase 2/3 type of trial, if promising, could be used to get regulatory approval in a fast-tracked situation like COVID-19. In these situations, there is usually some surrogate marker of a successful immune response in the individuals that received the test vaccine. This is still an open question for COVID-19.
The final step toward government approval begins with filing of a Biologics License Application (BLA), as it is called in the U.S. The BLA preparation, review, licensure, and vaccine launch, usually requires 18 to 24 months. Regulators are reviewing COVID-19 technologies on an expedited basis, so this timeline would be compressed in the U.S., and around the world to potentially weeks rather than months or years.
The Wait for a Vaccine
The investments that have been made in COVID-19 vaccine research are significant, but it will take time and patience for a vaccine to become available. It is hoped that a drug therapy may become available in the meantime to alleviate the more serious effects of COVID-19 in some individuals thereby reducing the burden on the health care system. As the SARS-Cov 2- (COVID-19) is a novel virus hospitals, universities, governments and companies are collaborating to help reduce the timelines for drug therapies by relying on each other’s drug expertise. Some are relying on repurposing and testing existing drugs that have an activity that may be useful in SARS-Cov 2- (COVID-19) active infection situation by blocking viral entry in to human cells (ie cloroquine) or others that are viral replication inhibitors (see for a list of drugs Diabetes Metab Syndr. 2020 May-June; 14(3): 241–246.)
Even though there is an intensive ongoing search for therapies, a vaccine is still considered to be an essential long-term weapon against COVID-19. Therapeutic drugs are useful to treat already infected individuals. In the long term, particularly if this virus has the potential to be seasonal and mutate, the best intervention is a prophylactic (vaccine) approach, not unlike what is available for seasonal flu.
As of early April 2020 there were at least 78 confirmed candidate vaccines programs in development. This has grown as of mid-June 2020 to about 125 candidate vaccines at a preclinical stage and 16 in clinical evaluation (WHO “Draft landscape of COVID-19 candidate vaccines”). The most advanced are mRNA, Adenovirus vector, plasmid DNA, all expressing viral spike protein and in Phase 1/2 or entering Phase 2 clinical trials. Many different approaches are being investigated from classical inactivated whole virus to protein-based and vector delivery approaches. This varied approach will give a better chance of finding an efficacious vaccine.
It is unlikely that no single entity, private or public, can produce enough vaccine or vaccine plus adjuvant on their own to supply a world-wide demand. It is only with international public, academic, government and industry collaboration that an effective COVID-19 vaccine can be produced in as short a time as possible. Vaccine IP can be licensed rapidly to partners. The WHO has also developed its own plan to scale up vaccine production and distribution. As of today, a vaccine in 2020 is unlikely (described as “aspirational” by Dr. Fauci). A more realistic timeline for a vaccine is estimated as 12-18 months away, which would still be unprecedented for this type of vaccine project. All the pieces of the developmental stages have to work nearly perfectly to meet this projected date. The manufacturing capacity to make the vaccine also needs to be a coordinated global effort. It is also likely that there will have to be a roll-out of a vaccine to the most at risk individuals (health-care workers, individuals with pre-existing health issue) first, as the multiple billions of doses needed may not be able to be produced in such a short time after identification of a candidate vaccine.
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