FDA Advisory Committee Votes in Favor of COVID-19 Vaccine BNT162b2

The FDA's Vaccines and Related Biological Products Advisory Committee has voted 17-4 with 1 abstention to support the benefit-risk profile associated with the coronavirus disease 2019 vaccine BNT162b2.

Recently, the vaccine co-developer Pfizer, released data from a pivotal phase 3 trial (NCT04368728), which demonstrated that among 43,448 patients, the vaccine demonstrated a 95% efficacy in preventing COVID-19 infection in those without previous infection 7 days or longer following the second dose of treatment.

Notably, efficacy with the vaccine noted in the overall patient population proved to be consistent across different subsets analyzed, such as age, gender, race, ethnicity, baseline body mass index, or the presence of other underlying comorbidities.

Among 36,523 patients with no evidence of existing or prior SARS-CoV-2 infection at the time of immunization, 170 cases of COVID-19 were reported with onset at least 7 days following the second dose. Of those cases, 8 occurred in those who received the vaccine and 162 in those who received placebo; this translated to vaccine efficacy of 95.0% (95% CI, 90.3-97.6).

Furthermore, among patients with and without evidence of previous infectious with SARS-CoV-2, COVID-19 was reported in 9 vaccine recipients and 169 placebo recipients, translating to a vaccine efficacy of 94.6% (95% CI, 89.9-97.3).

“These pivotal data demonstrate that our COVID-19 vaccine candidate is highly effective in preventing COVID-19 disease and is generally well-tolerated. They are a testament to the extraordinary efforts to deliver an effective vaccine with a favorable safety profile rapidly and serve as the basis for our regulatory submissions around the world,” Kathrin U. Jansen, PhD, senior vice president and head of Vaccine Research & Development at Pfizer, stated in a press release on the results. “As COVID-19 cases continue to rise and ravage the lives of so many people, we hope that these data will build confidence in the global health opportunity for vaccines to help us combat this devastating pandemic.”

The ongoing phase 3 trial of the vaccine had enrolled over 44,000 participants, and the majority of these patients have been administered their second dose. Patients were enrolled at about 150 clinical sites throughout the United States, Germany, Turkey, South Africa, Brazil, and Argentina.

In the observer-blind study, patients were randomized 1:1 to receive the vaccine or placebo. The study was comprised of 2 parts. In phase 1, investigators sought to identify preferred vaccine candidates and dose levels, while the phase 2/3 portion evaluated efficacy in an expanded cohort of patients.

The primary end points of the trial include prevention of COVID-19 in those who had not been infected with SARS-CoV-2 before immunization and prevention of COVID-19 irrespective of whether patients had prior SARS-CoV-2 infection. Secondary end points included prevention of severe COVID-19 in those subsets. Additionally, investigators are evaluating whether the vaccine can prevent SARS-CoV-2, as well.

Additional results from the trial showed that the cumulative incidence of COVID-19 cases over time in both arms started to separate by 12 days following the first dose. Moreover, a vaccine efficacy of 52.4% (95% CI, 29.5-68.4) was noted between dose levels 1 and 2; this suggests that early onset of a partially protective effect of vaccination. Maximum protection with the vaccine was observed at 2 doses.

"The demonstration of the safety and tremendous efficacy of multiple SARS-CoV-2 vaccines is a huge win for science and for humanity. I look forward to strongly recommending that my patients take the vaccine [if approved and] available, including those receiving active chemotherapy or other anti-neoplastic treatment," Nancy U. Lin, MD, associate chief of the Division of Breast Oncology at Susan F. Smith Center for Women's Cancers; director of the Metastatic Breast Cancer Program, director of the Program for Patients With Breast Cancer Brain Metastases, and senior physician at the Dana-Farber Cancer Institute told OncLive. "At the same time, given lack of data regarding the effects of chemotherapy or targeted therapies on vaccine immunogenicity or efficacy, greater inclusion of cancer patients in vaccine clinical trials is absolutely critical and should be a priority moving forward."

The vaccine showed an acceptable toxicity profile with favorable tolerability. A total of 37,706 patients had a median of 2 months of safety information available following dose 2; this information contributed to the main safety dataset. The most frequently reported toxicities with the vaccine included transient, mild to moderate pain at the injection site, fatigue, and headache. Notably, these toxicities would typically resolve within 2 days.

With regard to any unique concerns regarding mRNA vaccines in patients with cancer, Balazs Halmos, MD, a professor of medicine at Albert Einstein College of Medicine and director of the Thoracic Head and Neck Program at Montefiore Medical Center, told OncLive: “We need to consider this from 2 angles: safety and efficacy. We will need to make calls for our patients without data, as those with a known cancer diagnosis could not participate in these studies.”

He added that because these vaccines are mRNA-based, there is no risk of infectivity; however, other toxicities may need to be monitored, such as additional immune-related AEs within the context of checkpoint inhibitor treatment, according to Halmos. “Risk appears quite low though, as many other vaccines we are able to give without notable added AEs. All in all, the potential benefit seems to greatly outweigh safety concerns and I personally will recommend these vaccines early to my patients [if they are approved].”

Reference

Pfizer and Biontech announce publication of results from landmark phase 3 trial of BNT162B2 COVID-19 vaccine candidate in the New England Journal of Medicine. News release. Pfizer and BioNTech SE. December 10, 2020. Accessed December 10, 2020. https://bit.ly/3qNpUbN.