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Lopinavir-ritonavir trial results ‘disappointing’ for severe COVID-19



No difference in the primary endpoint of the time to clinical improvement was seen in an open-label trial of the antiretroviral drug lopinavir-ritonavir versus standard of care in adult patients hospitalized with severe COVID-19.

The median time to clinical improvement – defined as the time from randomization to either an improvement of two points on a seven-category ordinal scale or discharge from the hospital, whichever was first – was 16 days in both groups (hazard ratio, 1.31; 95% confidence interval 0.95-1.85; P = .09).

Although a numerically lower number of deaths were recorded at 28 days (19.2% vs. 25%) with the antiretroviral treatment versus standard of care, a similar percentage of patients had detectable levels of viral RNA in throat swabs taken at various time points during the study, Chinese researchers reported in the New England Journal of Medicine.

Bai Cao, M.D, from the China-Japan Friendship Hospital and Chinese Academy of Medical Sciences, both in Beijing, and associates, performed a randomized, controlled, trial of 199 adult patients hospitalized at the Jin Yin-Tan Hospital in Wuhan in Hubei Province, China.

For inclusion, patients had to have laboratory confirmed infection with SARS-Cov-2, the virus that causes COVID-19; pneumonia confirmed by chest imaging; and severely reduced oxygen saturation (94% or less while breathing ambient air or a ratio of the partial pressure of oxygen to the fraction of inspired oxygen of less than 300 mm Hg).

Patients were randomized to receive either a combination of lopinavir (400 mg) and ritonavir (100 mg) twice a day on top of standard care (n = 99) or to standard care alone (n = 100) for 14 days. “Because of the emergency nature of the trial, placebos of lopinavir-ritonavir were not prepared,” Dr. Cao et al. explained, noting that standard care consisted of supplemental oxygen, ventilation, antibiotic treatment, vasopressor support, renal-replacement therapy, and extracorporeal membrane oxygenation.

While the trial did not meet its primary endpoint, Dr. Cao et al. reported that patients in the lopinavir-ritonavir group had a shorter stay in the intensive care unit than did those in the standard-care group, at a median of 6 versus 11 days. They also reported that the duration from randomization to hospital discharge was numerically shorter, at a median of 12 versus 14 days. Furthermore, there was a higher percentage of patients with clinical improvement at day 14 in the lopinavir-ritonavir group than in the standard-care group (45.5% vs. 30.0%)

“The trial was initiated in rapid response to the COVID-19 public health emergency, at which time there was very limited information about clinical outcomes in hospitalized patients with COVID-19,” the researchers observed. “The question of whether earlier lopinavir-ritonavir treatment in COVID-19 could have clinical benefit is an important one that requires further study,” they wrote.

Among the trial’s limitations are it was not blinded and the researchers do not have data on the lopinavir exposure levels in the trial participants.

“This was a heroic effort” in a “particularly challenging population,” Lindsey R. Baden, MD, and Eric J. Rubin, MD, stated in an editorial accompanying the article (Baden LR and Rubin EJ. New Engl J Med. March 18, 2020. doi: 10.1056/NEJMe2005477). “Unfortunately, the trial results were disappointing,” they noted.

“The secondary end points provide both reason for hope and reason for discouragement,” wrote Dr. Baden and Dr. Rubin. The lack of effect on viral shedding, however, “strongly [suggests] that it did not have the activity desired” they observed.

Dr. Baden and Dr. Rubin commented that one of the important takeaways from the trial is that “the investigators appropriately prioritized speed, designing a trial that could rapidly produce an answer.” They continued that the investigators had shown that “rapidly initiated, high-quality randomized clinical trials are possible in epidemic conditions” and that results of such trials, whether they are positive or negative, “will be central to clinical care as the dangerous coronavirus outbreak continues.”

As it stands, more than 100 trials are listed in the database as testing a wide range of different treatment approaches for COVID-19. These include trials investigating if sarilumab, hydroxychloroquine, fingolimod, bevacizumab, and losartan might have a role to play. There are also trials looking at the potential of other antiviral agents, such as Gilead’s investigational drug remdesivir, which has shown to have in vitro and in vivo activity against many emerging viral pathogens that cause Ebola, Middle Eastern Respiratory Syndrome, and Severe Acute Respiratory Syndrome.

Dr. Cao’s trial was supported by grants from Major Projects of National Science and Technology on New Drug Creation and Development and from the Chinese Academy of Medical Sciences (CAMS) Emergency Project of Covid-19, and a National Science Grant for Distinguished Young Scholars.

All authors had no financial conflicts of interest to disclose.

Dr. Baden is the director of clinical research in the Division of Infectious Diseases at the Brigham and Women’s Hospital and the director of infectious diseases at the Dana-Farber Cancer Institute. He is a deputy editor of the New England Journal of Medicine and chair of the FDA’s Antimicrobial Drug Advisory Committee. He is involved in HIV vaccine clinical trials and has received research grants from the Ragon Institute, the National Institutes of Health/National Institute of Allergy and Infectious Diseases, and the Gates Foundation.

Dr. Rubin is employed by the New England Journal of Medicine as editor-in-chief. He is an associate physician at Brigham and Women’s Hospital and is chair and Irene Heinz Given Professor of Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health.

SOURCE: Cao B et al. New Engl J Med. 2020 Mar 18. doi: 10.1056/NEJMoa2001282.

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