Recent papers on convalescent plasma and on ACE inhibitors and angiotensin receptor blockers
This article includes recent papers that add to the knowledge of investigational approaches to treat COVID-19, that are currently in clinical studies in the UK.
The previous edition of HTB included a review of studies looking at convalescent plasma to treatment COVID-19. 
A further study – the largest so far – has recently reported no benefit. 
The investigators reported a 7-day mortality rate of 14.9%, which is similar to the natural history of severe COVID-19. The incidence of severe adverse events was <1%.
An editorial viewpoint in JAMA also discusses this research in more detail. 
A third study was that randomised 103 participants with severe or life-saving COVID-19 to either open-label convalescent plasma or standard of care reported no difference in clinical recovery or PCR changes by day 28. Evolving standard of care during the study included antiviral medications, antibacterial medications, steroids, human immunoglobulin, Chinese herbal medicines, and other medications. However, this study was original planned to include 200 participants but was closed early due to lack of new cases after COVID-19 was contained in China. 
ACE inhibitors and angiotensin receptor blockers
HTB previously reported on the potentially beneficial impact of ACW inhibitors and angiotensin receptor blockers (ACEI/ARBs), previously reported in HTB. [5, 6]
Several papers have added to this literature, including a study in JAMA reporting that ACEI/ARB therapy is not associated with increased susceptibility to SARS-CoV-2 infection or increased severity of COVID-19. This was based on 30-day mortality in a retrospective cohort of 4480 patients with COVID-19 (adj HR: 0.83 [95% CI: 0.67 to 1.03]). A nested case-control analysis within a cohort of 494,170 patients with hypertension also concluded that among patients with pre-existing hypertension, those receiving ACEI/ARBs did not have a significantly higher risk of acquiring COVID-19 than patients receiving other antihypertensive medications (HR: 1.05 [95% CI: 0.80 to 1.36]). 
An accompanying editorial is again useful for reviewing this data in the context of other research. 
Although this study confirms that ACEI/ARBs are safe to continue in context of COVID-19, they didn’t report a beneficial effect.
- Collins S. Convalescent plasma therapy for COVID-19. HTB, supplement (4). (1 June 2020).
- Joyner M, Wright S, Fairweather D, et al. Early safety indicators of COVID-19 convalescent plasma in 5,000 patients. medRxiv. DOI:10.1101/2020.05.12.20099879. (14 May 2020).
- Marovich M et al. Monoclonal antibodies for prevention and treatment of COVID-19 JAMA viewpoint.DOI: 10.1001/jama.2020.10245. (15 June 2020).
- Li L et al. Effect of convalescent plasma therapy on time to clinical improvement in patients with severe and life-threatening COVID-19: a randomized clinical trial. JAMA. DOI:10.1001/jama.2020.10044. (3 June 2020).
- Mascolini M. ACE inhibitors and angiotensin receptor blockers for hypertension tied to lower death risk with COVID-19. HTB (14 May 2020).
- Mascolini M. ACE inhibitors and angiotensin receptor blockers do not boost risk of COVID-19 or flu. HTB (14 May 2020).
- Fosbøl EL et al. Association of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use with COVID-19 diagnosis and mortality. JAMA. DOI: 10.1001/jama.2020.11301. (19 June 2020).
- Curfman G et al. Renin-angiotensin-aldosterone inhibitors and susceptibility to and severity of COVID-19. JAMA. Editorial commentary. DOI: 10.1001/jama.2020.11401. (19 June 2020).