Nirmatrelvir–ritonavir targeting viral persistence in post-COVID-19 condition long COVID in the USA RECOVER-VITAL…, 2026, Baden+

SNT Gatchaman

Senior Member (Voting Rights)
Staff member
Nirmatrelvir–ritonavir targeting viral persistence in post-COVID-19 condition long COVID in the USA RECOVER-VITAL: a randomised, double-blind, placebo-controlled, phase 2 trial
Lindsey R Baden + 253 others

BACKGROUND
Post-acute sequelae of SARS-CoV-2 infection, more commonly known as long COVID, has emerged as a major health problem. The pathogenesis of long COVID is unknown, but among the leading hypotheses is viral persistence. We aimed to investigate whether the use of the SARS-CoV-2 antiviral nirmatrelvir–ritonavir improved long COVID symptoms.

METHODS
We conducted a double-blind, placebo-controlled, randomised trial involving adults who had developed persistent symptoms (≥12 weeks) associated with three major symptom phenotypes (cognitive, autonomic, or exercise) after acute SARS-CoV-2 infection at 69 US sites. Participants were eligible if they were 18 years or older and had a previous suspected, probable, or confirmed SARS-CoV-2 infection, as defined by the Pan American Health Organization. Eligible participants were also required to have either at least two moderate symptoms from the same phenotype or one severe phenotype-associated symptom, as identified with the Cluster Targeted COVID-19 Symptom Questions. Participants were randomly allocated in a double-blind manner in a 1:1:1 ratio using permuted blocks of size 30 to receive either 15 days of active intervention followed by 10 days of placebo (300 mg nirmatrelvir–100 mg ritonavir twice daily, then 100 mg ritonavir–placebo); 25 days of active intervention (300 mg nirmatrelvir–100 mg ritonavir twice daily); or 25 days of placebo–ritonavir (100 mg ritonavir–placebo). A clinically significant change in patient-reported outcomes at day 90 comprised the primary endpoint: Patient-Reported Outcomes Measurement Information System Cognitive Function Short Form 8a, Orthostatic Hypotension Questionnaire question 1, and a modified version of the DePaul Symptom Questionnaire Post-Exertional Malaise short form. Secondary outcomes were phenotype-specific performance measures. The study was registered at ClinicalTrials.gov (NCT05595369) and is complete.

FINDINGS
Between July 27, 2023, and Sept 6, 2024, 1207 individuals were screened. Of these, 964 were randomly allocated and 959 participants, excluding four participants who were later found ineligible and one who did not initiate treatment, were enrolled in the three phenotypes: 332 to cognitive, 334 to autonomic, and 332 to exercise. In the 959 participants in the mITT population, 643 (67%) self-reported as female, 314 (33%) were male, and two participants had a sex of unknown or undifferentiated; 750 (78%) were White; and 108 (11%) were Hispanic, Latino, or Spanish. The median age was 49 years (IQR 38–59). No statistically significant benefits were observed for any phenotype for primary endpoints. For the cognitive phenotype, adjusted differences compared to placebo were 3·2% (95% CI –10·4 to 16·8, p=0·65) for the 25-day regimen and –2·2% (–15·5 to 11·1, p=0·74) for the 15-day regimen. For the autonomic phenotype, adjusted differences were –6·4% (–18·5 to 5·7, p=0·30) for the 25-day regimen compared to placebo and –0·1% (–12·5 to 12·3, p=0·99) for the 15-day regimen compared to placebo. For exercise, adjusted differences were –7·8% (–19·5 to 3·8, p=0·19) for the 25-day regimen compared to placebo and 0·9% (–11·4 to 13·2, p=0·88) for the 15-day regimen compared to placebo. There were no differences in secondary endpoints, and no safety signals were observed; there were no deaths, and 52 serious adverse events occurred in 42 (4%) of 963 participants over the course of the study.

INTERPRETATION
Nirmatrelvir–ritonavir for 15 days or 25 days showed no evidence of benefit in long COVID in any of the three phenotypes studied. These findings suggest additional approaches to measuring the symptom burden and treating Long COVID are needed.

FUNDING
National Institutes of Health.

Web | DOI | PDF | The Lancet Infectious Diseases | Open Access
 
I was initially worried about the timespan for the medication because it's less than a month, but that seems to be more than the average course for Paxlovid (which is 5 days according to this paper). I'm just used to long-term medications. I'm actually glad they tested 15 and 25 days to have a long course and an even longer one.

The differences between the treatments and the placebo in each cohort clearly show no benefit.
For the cognitive phenotype, improvement occurred in 58% (59 of 102) of participants assigned to nirmatrelvir–ritonavir 25 days, 53% (59 of 111) of participants assigned to nirmatrelvir–ritonavir 15 days, and 55% (53 of 97) of participants assigned to placebo–ritonavir. Relative to placebo, adjusted differences were 3·2% (95% CI –10·4 to 16·8, p=0·65) for the 25-day regimen and –2·2% (–15·5 to 11·1, p=0·74) for the 15-day regimen.
For the autonomic phenotype, improvement was observed in 62% (73 of 117), 70% (67 of 96), and 70% (73 of 104) of participants assigned to nirmatrelvir–ritonavir 25 days, nirmatrelvir–ritonavir 15 days, and placebo–ritonavir, respectively, with adjusted differences of –6·4% (95% CI –18·5 to 5·7, p=0·30) for the 25-day regimen compared to placebo and –0·1% (–12·5 to 12·3, p=0·99) for the 15-day regimen compared to placebo.
For the exercise phenotype, criteria for improvement were met by 25% (27 of 106) of participants assigned to nirmatrelvir–ritonavir 25 days, 34% (34 of 101) of participants assigned to nirmatrelvir–ritonavir 15 days, and 33% (36 of 110) of participants assigned to placebo–ritonavir. Again, comparisons with placebo did not indicate a treatment effect for the 25-day regimen (adjusted difference –7·8% [95% CI –19·5 to 3·8], p=0·19) or the 15-day regimen (0·9% [–11·4 to 13·2], p=0·88).

@Hutan Was it you that had the list of RECOVER trials with a note for each one that has failed? Time to add another to the list.
 
Interesting comment on subjective vs objective measures [primary outcomes were PROMs, secondary outcomes were performance measures, more on what those were below]:
An important set of observations from this study is the behaviour of phenotype-specific outcome measures in the placebo–ritonavir group. Across all three phenotypes, substantial percentages of participants showed improvement over time by PROMs and less so by performance measures. Although the Hawthorne effect is commonly seen in clinical trials, perhaps due to attention and care during the course of a trial, the proportion improving in RECOVER-VITAL exceeded assumptions used for initial sample size calculations, perhaps limiting the possibility of detecting effect with the final sample size. Importantly, this background rate of improvement is not believed to be due to low-dose ritonavir administered to each group to maintain masking; previous studies suggested no meaningful biological activity of ritonavir against SARSCoV-2, especially when used at a low dose.30 Nonetheless, the high proportion improving in the placebo–ritonavir group cautions against overinterpretation of uncontrolled observations and highlights the need for placebo control in studies of long COVID to better define therapeutic improvement rather than variation of symptomatology over time.

I'm unclear why they pick out the placebo-ritonavir group specifically.

From table 2:
1788360351182.webp

Secondary outcomes for each phenotype [breaks and bolding inserted for easier reading]:
The primary endpoint for each phenotype was the proportion of participants achieving a clinically meaningful improvement as assessed by phenotype-specific PROM at day 90 compared to baseline. Clinically significant improvement for each phenotype was supported by literature in non-long COVID populations24–27 and defined as follows:

for cognitive, an increase by at least 5 T-score points on the Patient-Reported Outcomes Measurement Information System (PROMIS) Cognitive Function Short Form 8a;

for autonomic, a decrease by at least one rating scale category on a modified version of the Orthostatic Hypotension Questionnaire (OHQ) question 1; and

for exercise, absence of any moderate, severe, or very severe symptoms occurring 50% or more of the time as assessed by a modified version of the DePaul Symptom Questionnaire Post-Exertional Malaise (DSQ-PEM) short form.

Secondary outcomes for each phenotype [breaks and bolding inserted for easier reading]:
Secondary endpoints were based on the proportion of participants obtaining clinically meaningful improvement on phenotype-specific performance measures, which was assessed at day 90 compared to baseline and defined as follows:

for cognitive, an increase by 0·5 SD in either the WHO–University of California Los Angeles Auditory Verbal Learning Test delayed recall measure or Symbol Digit Modalities Test number of correct substitution measure, and no decrease exceeding 0·15 SD in either of these measures;

for autonomic, either a decrease in heart rate by at least 10 beats per minute or an increase in systolic blood pressure by at least 10 mm Hg, or an increase in diastolic blood pressure by at least 5 mm Hg, and no increase in heart rate or decrease in systolic or diastolic blood pressure compared to baseline on the active stand test at 10 min; and

for exercise, an increase by at least 3 min in walking time on the Endurance Shuttle Walk Test.
 
Putrino’s twitter responses to this trial are rather disappointing. It’s never it didn’t work, just we need to do xyz. Null results are important for reflection of your hypothesis. It feels like there will always be a cop out. I still can’t believe he’s the face of most research.
 

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Putrino’s twitter responses to this trial are rather disappointing. It’s never it didn’t work, just we need to do xyz. Null results are important for reflection of your hypothesis. It feels like there will always be a cop out. I still can’t believe he’s the face of most research.
It's quite crazy to see someone talk about the need for subttyping when this study did exactly that. How could you further subtype this study when they did three groups? And the timing stuff when they already compared 15 days and 25 days. It seems, as you said, Putrino and his followers can't accept a null result.
 
Well, you can always come up with a new way of grouping patients into subgroups. I don't remember how many clustering papers in LC I've seen. Each one of them is of course novel and has the potential to transform clinical trials, treatments and care pathways for those affected. The stated potential is huge. The practical reality is that none of them has done that and given the number of such papers, I think the clustering/subtyping attempts are futile at present because they rely on symptoms and noise rather than meaningful biological signals.
 
This should be plastered in every lab that is doing trials for ME/CFS and Long Covid.
Agreed.

What this study shows is that a lot of people across various "sub-types" of Long Covid (with very broad inclusion criteria), will think they improve with time and answer that they are doing better on a follow up survey 9-12 months later.
Regardless of intervention. And even if the objective measurements show otherwise.

It's not what the researchers set out to do, but it ironicallly actually makes a strong case for why subjective outcomes are worthless and any study not using objective measures like HR, HRV, step counts, autonomic and/or cognitive tests, biological measurements, etc. should be mostly ignored.

It's baffling to me how much of the conversation online about this trial has been about the drug itself, and either dunking on or defending one theory or another (viral persistence), and is missing this bigger point.
 
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