Efficacy of Pfizer's Covid pill holds up in final analysis, reducing risk of hospitalization or death by almost 90%
The drastic difference in efficacy for Merck’s Covid-19 pill between interim and final analyses — from a 50% relative reduction in hospitalizations and deaths at the interim to just 30% in the final results — had some worrying that the Pfizer pill’s early success for adults at high risk of hospitalization might also be more muted in the final results.
But that wasn’t the case early Tuesday as Pfizer said that final data available from the more than 2,200 high-risk patients enrolled in its trial confirmed prior results showing Paxlovid reduced the risk of hospitalization or death by 89% (within three days of symptom onset) and 88% (within five days of symptom onset) compared to placebo. The company added:
0.7% of patients who received PAXLOVID were hospitalized through Day 28 following randomization (5/697 hospitalized with no deaths), compared to 6.5% of patients who received placebo and were hospitalized or died (44/682 hospitalized with 9 subsequent deaths). The statistical significance of these results was high (p<0.0001).
The data have already been shared with the FDA as part of an ongoing rolling EUA submission, Pfizer said.
And the FDA may act soon on Pfizer and Merck’s pills, both of which need to be taken over five days, and both of which seem to hold up against the Omicron variant.
But there may be certain restrictions on who should access the pills, and some lingering concerns on the Merck pill’s mechanism of action. For instance, the FDA is unlikely to authorize Merck’s pill in pregnant women, due to the potential for fetal toxicities, or those who have been vaccinated because they were not included in the pivotal trial.
And the Merck pill’s MOA, which drives the mutagenesis of the SARS-COV-2 virus to kill it off, could theoretically increase the likelihood of variants as a result of widespread treatment. But so far those fears are theoretical, and Merck narrowly won the backing of an adcomm for its EUA about two weeks ago.
Once the pills are authorized by the FDA, supplies should be distributed shortly thereafter. The US last month paid $5.29 billion for 10 million courses of the Pfizer pill, and for Merck’s pill, the US has now purchased more than 3 million courses for about $2.2 billion so far.