CORRESPONDENCE 87 C.S. Kow a,* , S.S. Hasan b,c a School of Postgraduate Studies, International Medical University, Kuala Lumpur, Malaysia b Department of Pharmacy, University of Huddersfield, Huddersfield, United Kingdom c School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia * Corresponding author. E-mail address: chiasiang 93@hotmail.com (C.S. Kow). 2 October 2020 https://doi.org/10.1016/j.pulmoe.2020.10.004 2531-0437/ © 2020 Sociedade Portuguesa de Pneumologia. Published by Elsevier Espa˜ na, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). Rationale and evidence on the use of tocilizumab in COVID-19: A systematic review. Authors’ reply Dear Editor, We read with interest the Letter from Siang Kow et al. 1 com- menting on our systematic review 2 and their discussion of the preliminary evidence from recent randomized controlled trials (RCTs) on the efficacy and safety of tocilizumab for COVID-19. We concur with the authors that it may indeed be time to divert some of our attention from IL-6 to other mediators of inflammation in COVID-19 patients. In fact, previous pharmacological attempts to modulate the inflam- matory response in patients with ARDS and sepsis have repeatedly proven unsuccessful. It is therefore reasonable to also question whether suppressing the pathophysiologi- cal inflammatory response, or blocking a single mediator for that matter, will be beneficial for patients with COVID-19. The authors commented on the absence of significant difference in mortality between patients who received tocilizumab (Actemra/RoActemra) or placebo in the industry funded COVACTA (NCT04320615 - https://www. roche.com/dam/jcr:6d8de90d-2e31-43c8-b4e1-0a24a2675 015/en/29072020-mr-covacta.pdf) and EMPACTA (NCT04372186 - https://www.roche.com/media/releases/ med-cor-2020-09-18.htm) trials. The results of these trials confirm that findings from non- randomized trials should be interpreted with caution and that such caution is warranted particularly during public health emergencies when large numbers of patients may subsequently receive redundant treatments. As discussed by the authors in the context of tocilizumab and exempli- fied also by the hydroxychloroquine landslide, 3 experimental drugs are not always harmless, particularly when indiscrim- inately used. Patient safety should always be prioritized, which is why experimental drugs must be administered within the framework of registered RCTs that are accom- panied by appropriate monitoring and regulation. Research methodology may have also contributed to the negative findings of the above-mentioned RCTs. One exam- ple of a potential determinant of outcome in relation to treatment is the timing of administration in respect to the clinical phase of the disease. 4 Another is the treatment dose. Case mix may also have diluted the results; there may be sub-populations of COVID-19 patients who do actually ben- efit from receiving tocilizumab. Hopefully the full reports of the COVACTA and EMBACTA trials will shed some light on these questions and more. These analyses combined with additional data from the interventional tocilizumab arm of the RECOVERY trial (www.recoverytrial.net) may yet change our perspective on this drug. To summarize, although oft repeated, the following rhetoric is simply the truth: more (high quality) research is urgently needed. Authors’ contribution AC, MI, SE conceived the content, drafted the manuscript and approved the final version for publication. Funding None. Conflicts of interest The authors have no conflicts of interest to declare. References 1. Kow CS, Hasan SS. Interleukin-6 blockade with tocilizumab in COVID-19: Does it live up to its hype? Pulmonology. 2020, http://dx.doi.org/10.1016/j.pulmoe.2020.10.004. 2. Cortegiani A, Ippolito M, Greco M, Granone V, Protti A, Gregoretti C, et al. Rationale and evidence on the use of tocilizumab in COVID-19: a systematic review. Pulmonology. 2020, http://dx.doi.org/10.1016/j.pulmoe.2020.07.003. Jul 20:S2531-0437(20)30153-7. 3. Cortegiani A, Ippolito M, Ingoglia G, Iozzo P, Giarratano A, Einav S. Update I. A systematic review on the effi- cacy and safety of chloroquine/hydroxychloroquine for COVID-19. J Crit Care. 2020;59:176---90, http://dx.doi.org/10.1016/j.jcrc.2020.06.019. 4. Furlow B. COVACTA trial raises questions about tocilizumab’s ben- efit in COVID-19. Lancet Rheumatol. 2020;2(10), e592. A. Cortegiani a,b,* , M. Ippolito a , S. Einav c a Department of Surgical, Oncological and Oral Science (Di.Chir.On.S.), University of Palermo, Italy b Department of Anesthesia, Intensive Care and Emergency, Policlinico Paolo Giaccone, University of Palermo, Palermo, Italy c Intensive Care Unit of the Shaare Zedek Medical Medical Centre, Hebrew University Faculty of Medicine, Jerusalem, Israel