New England Journal of Medicine DECEMBER 11, 2020

Baricitinib plus Remdesivir for Hospitalized Adults with Covid-19

Kalil AC, Patterson TF, Mehta AK, et al. (ACTT-2 Study Group)

Bottom Line

In this randomized, double-blind, placebo-controlled trial, the addition of the Janus kinase inhibitor baricitinib to remdesivir reduced time to recovery in hospitalized patients with COVID-19 compared to remdesivir monotherapy.

Key Findings

1. The combination of baricitinib and remdesivir resulted in a median time to recovery of 7 days, compared with 8 days for the remdesivir monotherapy group (rate ratio for recovery, 1.16; 95% CI, 1.01 to 1.32; P=0.03).
2. Patients receiving high-flow oxygen or non-invasive mechanical ventilation at enrollment experienced a more pronounced benefit, with a median time to recovery of 10 days in the combination group compared to 18 days in the control group.
3. The odds of improvement in clinical status at day 15 on an 8-point ordinal scale were significantly higher in the combination group compared to the control group (odds ratio, 1.3; 95% CI, 1.0 to 1.6).
4. The 28-day mortality rate was 5.1% in the baricitinib-plus-remdesivir group compared to 7.8% in the control group, though this difference did not reach statistical significance.

Study Design

Design
RCT
Double-Blind
Sample
1,033
Patients
Duration
29 days
Median
Setting
Multicenter, Global
Population Hospitalized adults with laboratory-confirmed SARS-CoV-2 infection and evidence of lung involvement (e.g., radiographic opacities or requirement for supplemental oxygen)
Intervention Oral baricitinib (4 mg daily) plus intravenous remdesivir (200 mg on day 1, then 100 mg daily for up to 10 days)
Comparator Placebo plus intravenous remdesivir (200 mg on day 1, then 100 mg daily for up to 10 days)
Outcome Time to recovery by day 29, defined as the first day on which the patient satisfied criteria for hospital discharge (no longer requiring supplemental oxygen or ongoing medical care)

Study Limitations

The trial was conducted in a rapidly evolving pandemic environment, which may affect the generalizability of results to different stages of the pandemic or different variants.
The study did not achieve statistical significance for the secondary endpoint of mortality reduction, indicating it was primarily powered for recovery time rather than mortality.
The study population was heterogeneous regarding the severity of illness at baseline, potentially masking effects in specific subgroups.

Clinical Significance

This study provided evidence for the use of anti-inflammatory therapy (baricitinib) in combination with antiviral therapy (remdesivir) for hospitalized COVID-19 patients requiring supplemental oxygen, supporting the regulatory Emergency Use Authorization at the time.

Historical Context

Following the success of ACTT-1 in demonstrating the efficacy of remdesivir, the ACTT-2 trial was designed as an adaptive, sequential study to evaluate whether adding an immunomodulatory agent (baricitinib) to the established antiviral standard of care could further improve patient outcomes.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What is the physiological rationale for combining a Janus kinase (JAK) inhibitor like baricitinib with an antiviral agent like remdesivir in patients with COVID-19?

Key Response

COVID-19 pathogenesis involves two distinct but overlapping phases: an early viral replication phase and a subsequent host inflammatory response. Remdesivir targets the viral RNA-dependent RNA polymerase to inhibit replication, while baricitinib inhibits JAK1 and JAK2, blocking the signaling pathways of pro-inflammatory cytokines (like IL-6) that drive the 'cytokine storm' and subsequent lung injury.

Resident
Resident

In the ACTT-2 trial, which specific subgroup of hospitalized patients showed the most pronounced clinical benefit from the addition of baricitinib to remdesivir, and how does this affect your bedside management?

Key Response

The most significant benefit was observed in patients requiring high-flow oxygen or non-invasive ventilation (ordinal scale 6) at enrollment, where the median time to recovery was reduced from 18 to 10 days. This suggests that baricitinib should be prioritized for patients who are progressing toward respiratory failure but have not yet required mechanical ventilation.

Fellow
Fellow

Given the 'black box' warnings for JAK inhibitors regarding venous thromboembolism (VTE), how do the ACTT-2 safety outcomes inform the use of baricitinib in a disease state like COVID-19 that is already known to be highly prothrombotic?

Key Response

Interestingly, ACTT-2 reported a similar or even lower rate of serious adverse events, including thromboembolism, in the combination group compared to the remdesivir-alone group. This may be because the systemic anti-inflammatory effects of baricitinib mitigate the overall hypercoagulable state induced by severe infection, though diligent VTE prophylaxis remains a standard of care.

Attending
Attending

How does the evidence from ACTT-2 challenge the current paradigm of using dexamethasone as the sole primary immunomodulator for COVID-19, particularly in patients where steroid side effects are a concern?

Key Response

ACTT-2 provides a high-quality alternative for patients where corticosteroids might be contraindicated or high-risk (e.g., uncontrolled diabetes, secondary infections). It demonstrates that targeted cytokine signaling inhibition is a viable, and perhaps more precise, strategy for immunomodulation compared to the broad, non-specific effects of high-dose steroids.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The ACTT-2 trial utilized an ordinal scale-based 'time to recovery' as its primary endpoint. What are the statistical advantages and limitations of this approach compared to a traditional 28-day mortality endpoint in the context of an emerging pandemic?

Key Response

Time to recovery increases the power of the study to detect treatment effects in survivors and is more sensitive to clinical improvements that don't necessarily result in death. However, it can be confounded by varying discharge criteria across institutions and may underpower the study to detect a true mortality benefit, necessitating secondary analyses or larger meta-analyses to confirm survival advantages.

Journal Editor
Journal Editor

A major criticism of the ACTT-2 trial is that it was conducted largely before dexamethasone became the global standard of care. As a reviewer, how would you address the lack of a dexamethasone-comparator arm when evaluating the study's impact on current clinical practice?

Key Response

The lack of a dexamethasone arm is a significant 'threat to external validity' because it leaves clinicians wondering if baricitinib adds value to the current standard of care. An editor would require the authors to explicitly discuss this limitation and would look for subsequent trials (like ACTT-4 or COV-BARRIER) to bridge the gap between baricitinib and corticosteroid therapy.

Guideline Committee
Guideline Committee

Based on the ACTT-2 findings, how should the strength of recommendation for baricitinib be graded for patients on high-flow oxygen, and should it be recommended as a replacement for or an adjunct to current steroid-based protocols?

Key Response

Current guidelines (e.g., NIH and IDSA) have integrated ACTT-2 evidence to recommend baricitinib typically in combination with dexamethasone for patients with rapidly increasing oxygen needs. While ACTT-2 alone supports a 'Strong, Moderate-Quality' recommendation for baricitinib + remdesivir, the presence of newer data (RECOVERY, COV-BARRIER) means guidelines now often favor baricitinib as an add-on to steroids rather than a standalone replacement, unless steroids are contraindicated.

Clinical Landscape

Noteworthy Related Trials

2020

ACTT-1 Trial

n = 1,062 · NEJM

Tested

Remdesivir

Population

Hospitalized adults with Covid-19

Comparator

Placebo

Endpoint

Time to recovery

Key result: Remdesivir shortened the time to recovery compared to placebo in hospitalized patients with Covid-19.
2020

RECOVERY Trial

n = 6,425 · NEJM

Tested

Dexamethasone

Population

Hospitalized patients with Covid-19

Comparator

Usual care

Endpoint

28-day mortality

Key result: Dexamethasone reduced deaths by one-third in patients receiving invasive mechanical ventilation and by one-fifth in those receiving only oxygen.
2021

RECOVERY-Tocilizumab Trial

n = 4,116 · Lancet

Tested

Tocilizumab

Population

Hospitalized patients with Covid-19 hypoxia and systemic inflammation

Comparator

Usual care

Endpoint

28-day mortality

Key result: Tocilizumab significantly reduced mortality and improved the chance of discharge for hospitalized Covid-19 patients with hypoxia and evidence of systemic inflammation.

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