This Week's COVID-19 Vaccine Update: No October Surprise, FDA's Big Meeting on Thursday, and UK Challenge Trials

October 20, 2020
Peter Wehrwein
Peter Wehrwein

Pfizer, Moderna executives say efficacy, safety data won't be ready till well after Election Day. FDA's COVID-19 vaccine meeting on Thursday says sure to draw a big crowd.

Doesn’t seem like we're headed for a COVID-19 surprise

Moderna CEO Stéphane Bancel said at a Wall Street Journal event yesterday that the company get an emergency use authorization in December if there are positive interim results from a clinical trial next month, according to the newspaper’s account of the event.

On Friday (October 16), Pfizer CEO Albert Bourla posted an open letter on the company website that said the company expected the vaccine it is developing with BioNtech to pass a safety milestone by the FDA in the third week of November and that assuming “positive data,” it will soon afterward. In August, Bourla was predicting that safety and efficacy data would be in hand in October.

Most touts of the COVID-19 vaccine race have Pfizer and Moderna in the lead, so as of this writing an emergency use authorization before the November 3 seems unlikely.

Many eyes on FDA vaccine meeting this Thursday, October 22

Stat’s Elizabeth Cooney says “nothing extraordinary is expected to happen” but it is a safe bet that a lot of more people will be tuning in the Center for Biologics Evaluation and Research’s (CBER), Vaccines and Related Biological Products Advisory Committee (VRBPAC) on Thursday.

Why? Maybe because the committee members will be discussing the small matter of the development, authorization and licensure of vaccines to prevent COVID-19.

Endpoints News Editor John Carroll reported this morning that the FDA has invited Jeannette Y. Lee, Ph.D., a professor in the Department of Biostatistics at the University of Arkansas for Medical Sciences and James E.K. Hildreth, Ph.D., M.D., the president and CEO of Meharry Medical College, to participate in the discussion.

The notice about the meeting on the FDA website says no specific application will be discussed. The start time is 10 a.m. You can watch the webcast here or watch it on the FDA’s Youtube channel

U.K. taking steps toward possible challenge trials

The question of whether to conduct challenge trials to hasten the collection of efficacy and safety data on the various COVID-19 vaccine candidates has been bandied about for months. Such trials would involve deliberating exposing vaccine trial volunteers to the SARS-CoV-2 virus that causes COVID-19 instead of — more likely, in addition to — conducting large phase 3 trials that depend on some circumstantial exposure to the virus to assess vaccine efficacy.

Christina Farr of CNBC is reporting this morning that the British government has taken a first step toward conducting a challenge study by contracting with Open Orphan, a niche contract research organization, for a "characterization study" that would identify the doses of the virus that might be used in a challenge study.

Nir Eyal, Marc Lipsitch and Peter G. Smith wrote about how challenge trials could be conducted ethically in the Journal of Infectious Diseases way back in March. Among the ingredients: healthy volunteers and access to top-drawer medical care in case anyone does develop a serious case of COVID-19.

Scientists raise warning about adenovirus 5 vector as COVID-19 vaccine vector

Several COVID-19 vaccine candidates use a presumably harmless variety of adenovirus — adenovirus 5 (Ad5) — as a delivery mechanism for the genetic material that produces the antigen that is stirs up an immune response against SARS-CoV-2 infection.

But the same “vector” was used in HIV vaccine trials, and some evidence suggested that Ad5 itselmight make some men more vulnerable to HIV infection.

“Roll-out of an effective SARS-CoV-2 vaccine globally could be given to populations at risk of HIV infection, which could potentially increase the risk of HIV-1 acquisition,” wrote the authors of a letter published in the Lancet yesterday. “This important safety consideration should be thoroughly evaluated before further development of Ad5 vaccines for SARS-Cov-2 and informed consent documents of these potential risks should reflect the considerable literature on HIV-1 acquisition with Ad5 vectors.”

The four authors of the letter — Susan P. Buchbinder, M. Juliana McElrath, Carl Dieffenbach and Lawrence Corey — are respected researchers.

In his story yesterday about the Lancet letter and the checkered background of Ad5 as an AIDS vaccine vector, Science’s Jon Cohen wrote that the results suggestive of a problem with Merck’s Ad5 vector sent AIDS vaccine research into a “tailspin.” Of course there's still no HIV-AIDS vaccine.

The “why” behind Ad5 and a possible link to greater risk of HIV transmission hasn’t been nailed down.

“Precisely how Merck’s Ad5 vaccine increased the risk of HIV transmission in STEP and Phambili [STEP and Phambili are the names of clinical trials] remains murky,” wrote Cohen. “The Lancet editorial spells out several possibilities, including the dampening of HIV immunity, enhancing replication of the AIDS virus, or setting up more target cells to it.”

State health officials to CDC: 60 cents per person is not enough

Friday, October 16, was the deadline for states and territories to submit their COVID-19 vaccination plans. Coming up with a plan with so many unknowns was difficult, health officials told several news sources. The Association of State and Territorial Health Officials (ASTHO) and the Association of Immunization Managers say the CDC has distributed $200 million to pay for the planning efforts but more money is needed to implement the plans.

“This funding [the $200 million] is a necessary first step but equals approximately 60 cents per person,” Claire Hannan, executive director of the Association of Immunization Managers said in press release issued last week. “It is not adequate to vaccinate every American with the expected two dose course at this amount.”

Today, ASTHO and the American Pharmacists Association announced that their representatives are co-chairing a new National COVID Vaccine Leadership Council to support implementation of the COVID-19 vaccination. The council has an impressive list of 19 member organizations, including the American Medical Association, the American Society of Health-System Pharmacists, the National Governors Association and the National Indian Health Board.