2020-10-19 Covid-19 Vaccine Race: Weekly Round-up

With the global count of Covid-19 cases fast approaching 40 million, the past seven days have certainly not been lacking in terms of activity on the Covid-19 vaccine race front.

With two leading vaccine studies being put on hold, the WHO’s Solidarity casting worrying doubts over remdesevir, it seems the race is now left open for two US pharma giants.

Monday, 12 Oct

The week started off with an announcement that J&J had paused its own Covid-19 trial to investigate an unexpected illness affecting one of the trial participants. The J&J pause is in addition to a halt imposed by regulators more than a month ago on the AstraZeneca/University of Oxford trial after neurological symptoms were reported in two volunteers. With the two paused and questions arising about the effectiveness and safety of adenoviral vectors, this seems to be paving the way for Moderna and Pfizer-BioNTech as they emerge as frontrunners in the race.

Tuesday, 13 Oct

On Tuesday, the focus shifted to Eli Lilly, after it reported that its own closely watched monoclonal antibody trial had also been paused over safety concerns. On the same day, the National Institutes of Health said it had paused the study after the trial’s independent data and safety monitoring board reported the study had reached a “predefined boundary for safety” after five days of treatment. However, no indication was provided regarding whether it was the treatment group or the placebo group that may have crossed a safety threshold. It is likely to take two weeks before more is disclosed regarding the fate of the trial.

Thursday, 15 Oct

As if the week was not eventful enough, a startling reveal by the WHO on Thursday that results from its much-anticipated 11,266 patient Solidarity trial showed remdesevir provided little or no effect on chances of survival or on the length of hospital stays among patients with the respiratory disease sent shockwaves across the world. With Gilead Sciences, the company that developed the drug questioning the scientific rigor behind the study, the WHO refused to back down and stood by its findings which are contrary to those from Gilead’s 1,062-patient trial which purported the drug cut recovery time by five days and helped reduce the risk of death in some patients who received oxygen.

To complicate matters, remdesivir had already received emergency use authorisation from the US FDA on May 1. In addition, the EU also authorized its emergency use and agreed to a €1bn remdesivir-supply deal on Tuesday, weeks after Gilead was reportedly informed by the WHO about its findings. Furthermore, the WHO’s trial also found that other medicines such as malaria drug hydroxychloroquine, anti-HIV drug combination lopinavir/ritonavir and interferon which have been repurposed since the pandemic began offered little or no benefit to Covid-19 patients. The hydroxychloroquine and anti-HIV studies were abandoned earlier in the year, and interferon was dropped on Thursday.

Friday, 16 Oct

More encouraging news came from Pfizer on Friday. The company reported that it could seek emergency-use authorization for its Covid-19 vaccine by late November if shown to be effective in its large late-stage trial. In an open letter published on the company’s website, the company’s Chief Executive Officer Albert Bourla mentioned the pharma giant should be able to meet the milestone to have at least half the study patients be watched for side effects for two months as required by the FDA in the third week of November.

So who's leading the race?

With questions being cast over adenoviral-based treatments, messenger RNA vaccine candidates developed by Moderna and the Pfizer-BioNTech partnership are seen to be leading the race. With the J&J and AstraZeneca/Oxford vaccine studies on hold for safety checks, this puts them significantly behind the two mRNA vaccines. Though Moderna is slightly behind Pfizer in the race, it is expecting to have preliminary efficacy data by the end of November – just a few days behind Pfizer’s. While both Pfizer and Moderna began their respective late-stage trials at the end of July, Pfizer is lightly ahead due to the speed at which it enrolled participants in its trial as well as its dosing regimen.