A Study of a Potential Oral Treatment to Prevent COVID-19 in Adults Who Are Exposed to Household Member(s) With a Confirmed Symptomatic COVID-19 Infection

Phase 2/3 Completed 2954 enrolled Pfizer

RandomizedParallel-groupQuadruple-blindPrevention

Summary

The purpose of this clinical trial is to learn whether the study medicine prevent symptoms of COVID-19 in adults who have been exposed to household member(s) with a confirmed symptomatic COVID-19 infection. All participants in the study will receive treatment for COVID-19 as needed, based on their regular doctor's recommendation. Two-thirds of participants will also receive two study medicines (PF-07321332 and ritonavir) by mouth twice a day for either five or ten days. We will compare the experiences of people receiving the study medicines to those of the people who do not. This will help us determine if the study medicines are safe and effective

Timeline

Start: 2021-09-09
Primary completion: 2022-04-12
Completion: 2022-04-12

Outcome

Missed primary endpoint

registry analysis (superiority test); Nirmatrelvir (PF-07321332) 300 mg + Ritonavir 100 mg 5 Days vs Placebo; p = 0.1722 NCT05047601 ↗

registry analysis (superiority test); Nirmatrelvir (PF-07321332) 300 mg + Ritonavir 100 mg 10 Days vs Placebo; p = 0.1163 NCT05047601 ↗

paper In this placebo-controlled trial, postexposure prophylaxis with nirmatrelvir-ritonavir for 5 or 10 days did not significantly reduce the risk of symptomatic SARS-CoV-2 infection. PMID 39018532 ↗

Publications

Hammond J, Yunis C, Fountaine RJ, Luscan G, Burr AM, Zhang W, Wisemandle W, Soares H, Baniecki ML, Hendrick VM, Kalfov V, Pypstra R, Rusnak JM. Oral Nirmatrelvir-Ritonavir as Postexposure Prophylaxis for Covid-19. N Engl J Med. 2024 Jul 18;391(3):224-234. doi: 10.1056/NEJMoa2309002.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Nirmatrelvir	Small molecule	300 mg	Oral
Background	Ritonavir	Other / unclassified	100 mg	Oral