PARIS (NYTIMES, AFP, REUTERS, BLOOMBERG) - Pharmaceutical companies Sanofi and GlaxoSmithKline (GSK) on Friday (Dec 11) said their experimental Covid-19 vaccine did not appear to work well in older adults, a significant setback to their late-stage clinical trial that was previously expected to begin in the United States this month.
The partners will begin a new Phase 2 study with a more concentrated product in February, after the current dosage failed to generate a good immune response in people 50 years and older. If the data is positive, a global Phase 3 study could start in the second quarter of next year.
The pair are also looking at doing a head-to-head trial with an approved Covid-19 vaccine to try to speed up research.
Delays and additional trials are not unusual, but the Sanofi-GSK announcement highlights the unique set of challenges facing drug makers in multi-tasking science, speed and logistics during a pandemic that has crushed global economies.
The setback affects one of the most established technologies in vaccines - used against the human papillomavirus, hepatitis B and pertussis, among other pathogens - which aims to introduce lab-made proteins into the body to prod the immune system into developing a targeted defence against Covid-19.
It cements the lead of more novel approaches used by vaccines from the likes of Pfizer-BioNTech and Moderna, which deploy mRNA genetic technology to trick the body into producing those proteins. Both of those shots were found to be about 95 per cent effective in successful large-scale trials. It underscores why governments have spread their bets by securing shots from different developers.
Sanofi said results from phases one and two trials showed "an immune response comparable to patients who recovered from Covid-19 in adults aged 18 to 49 years, but a low immune response in older adults likely due to an insufficient concentration of the antigen".
The vaccine's potential availability has been pushed back "from mid-2021 to Q4 2021", the drug-makers said in a statement.
Dr Jean-Daniel Lelievre, head of clinic immunology and infectious diseases at Henri-Mondor Hospital in Creteil, France, said: "With this type of vaccine, the result is not a surprise: We know that more antigen is needed in older patients. But when in Phase 1 and 2, drug makers test tolerance and one cannot test strong dosages."
He added: "I would think Sanofi and GSK will be able to improve their vaccine."
In a separate development, pharmaceutical giant AstraZeneca's Russian branch said on Friday that it would test a combination of its experimental Covid-19 vaccine with Russia's homemade Sputnik V vaccine in further clinical trials, a major sign of recognition for a jab that has been viewed with scepticism by the West.
Trials will start by the end of the year and Russia wants to jointly produce the new vaccine if it is proven to be effective, said the RDIF wealth fund, which funded Sputnik V. The vaccine is named after the Soviet-era satellite that triggered the space race.
While the Sputnik V jab uses human adenovirus vectors, AstraZeneca's AZD1222 relies on adenovirus from chimpanzees. Both are administered in two doses.
The partnership came about when the developers of Sputnik V suggested on Twitter last month that AstraZeneca try the combination after the British drug maker released interim results from its late-stage trial. The British drug maker accepted the proposal, the RFID said on Friday.