GSK, Clover part ways on COVID-19 vaccine, putting Dynavax in the spotlight

GSK's adjuvant wasn't selected by Clover for late-stage coronavirus vaccine testing. (Eric Sagonowsky)

First, lackluster data forced GlaxoSmithKline and partner Sanofi back to the drawing board with their COVID-19 shot. Now, the Big Pharma and a biotech partner are parting ways on a separate vaccine collaboration.

China's Clover Biopharmaceuticals had been testing its vaccine candidate with two adjuvants, one from GSK and the other from Dynavax. Adjuvants are designed to increase the effectiveness of a vaccine.

With phase 1 numbers in, Clover said it reviewed preclinical data and results from that trial—and took into account “manufacturing considerations”—in deciding to move forward with Dynavax's adjuvant in late-stage testing.

Knowing Clover had the option of using Dynavax's adjuvant, GSK decided not to proceed with the partnership, the company said in a statement. The decision was "based on a comprehensive analysis of the data available and an assessment of the scale and cost of development program that would be required for our continued participation," the company said.

The company is "pleased that the candidate vaccine will move forward with a different partner and hope that it is successful," a spokesman said. 

In the phase 1 study, the Clover vaccine—combined with either the GSK or Dynavax adjuvant—"performed well," the biotech said, and "induced high levels of neutralizing antibodies while demonstrating favorable safety and tolerability profiles."

RELATED: Using GSK and Dynavax tech, Clover kick-starts COVID-19 vax trial with data drop in August 

Now, Clover and Dynavax expect their study to start in the first half of the year. A potential interim efficacy result could come midyear. 

For GSK, the move comes after the vaccine giant and Big Pharma partner Sanofi late last year posted data showing their candidate failed to trigger the desired immune response in people 50 years and older. The companies now plan to start a phase 2b trial this month with a new antigen formulation, aiming for potential authorizations in the fourth quarter.

The Big Pharma partners aren't alone in having trouble in coronavirus vaccine research, though: Fellow vaccine expert Merck & Co. bowed out of the field last week after getting a late start.

Aside from Sanofi, GSK is also partnered with Medicago on a late-stage vaccine candidate and with Vir Biotechnology on coronavirus therapeutics. 

Clover, for its part, kicked off its coronavirus vaccine work last January and partnered with GSK last February. In April, the company scored backing from the Coalition for Epidemic Preparedness Innovations. Then, in July and November, CEPI and Clover expanded their collaboration as the program proceeded through various stages of testing. All told, CEPI has pledged up to $328 million to support the vaccine’s development. 

RELATED: Clover nears pivotal trial of GSK-adjuvanted COVID-19 vaccine 

CEPI is also supporting Dynavax now: On Monday, the group unveiled up to $99 million in funding as Dynavax works to manufacture its CpG 1018 adjuvant. The $99 million will come in the form of a forgivable loan and aims to support hundreds of millions of vaccine doses this year.  

The adjuvant stockpile will be available first for CEPI partners to purchase to support licensed vaccines, and remaining adjuvants can be sold to other CEPI partners to support their research. After Dynavax sells the adjuvant stockpile, it’ll reimburse CEPI for the manufacturing costs. If all the potential vaccines that could use the adjuvant fail in testing, CEPI will forgive the loan.