Sabizabulin is an oral microtubule disruptor with anti-viral properties that significantly reduced death among patients with severe COVID-19
The oral microtubule disruptor, sabizabulin has been shown significantly reduce the risk of death among patients hospitalised with COVID-19 and with a high risk of acute respiratory distress syndrome according to the results of a randomised, placebo-controlled trial by an international group of researchers.
The cellular cytoskeleton represents a complex and dynamic network of interacting protein filaments with multiple roles in the functioning of cells and is composed of three major types of protein filaments: actin filaments, intermediate filaments, and microtubules. During an infection, once a virus enters a cell, it requires cytoplasmic transport to reach specific sub-cellular sites for replication and the microtubules of the cytoskeleton represent a heavily exploited network during viral infection. Sabizabulin is a novel agent that disrupts the microtubule and hence interferes with viral replication. Moreover, in vivo data suggests that sabizabulin can suppress some of the key cytokines involved in the development of acute respiratory distress syndrome.
To test the benefit in practice of the drug, researchers undertook the VERU-111 trial which was designed to test the efficacy of VERU-111 (sabizabulin) in the treatment of COVID-19 infection. Eligible patients were adults with a laboratory confirmed COVID-19 infection, a World Health Organisation (WHO) 9-point ordinal scale for clinical improvement score of at least 4 (i.e., oxygen mask or nasal prongs), an elevated body mass index (BMI) and a co-morbidity known to place the individual at a high risk of more severe disease (e.g., asthma, diabetes, hypertension etc). Participants were randomised 2:1 to receive sabizabulin 9 mg daily or matching placebo for 21 days or until hospital discharge. The researchers set the primary efficacy endpoint as the level of 60-day all-cause mortality whereas secondary endpoints included differences in intensive care unit (ICU) days, the number of days on mechanical ventilation and time spent in hospital.
Sabizabulin and COVID-19 mortality
A total of 150 patients with a median age of 64 years (68% male) were included and randomised to sabizabulin (98) or placebo. For the entire study cohort, the median BMI was 31.7 and the median WHO ordinal scale score was 5. In addition, diabetes and hypertension were present in 37.3% and 60% of patients respectively. Overall, 55.3% of participants had not been vaccinated against COVID-19.
The primary outcome occurred in 20.2% of those taking sabizabulin and 45.1% of placebo patients, which was significantly different (odds ratio, OR = 3.23, 95% CI 1.45 – 7.22, p = 0.0042). In fact, researchers observed how the benefits of treatment with sabizabulin were apparent after only 3 days and there were significant differences in mortality seen by day 15.
For the secondary endpoints and based on a relative risk reduction, treatment with sabizabulin led to a 43% lower number of ICU days (p = 0.0013), a 49% decrease in the number of days requiring mechanical ventilation (p = 0.0013) and a 26% decrease in the number of days spent in hospital (p = 0.00277).
Adverse events leading to discontinuation of treatment occurred in 4.7% and 5.9% of patients receiving sabizabulin and placebo respectively.
The authors concluded that sabizabulin was both effective at reducing mortality in patients with COVID-19 and had an acceptable safety profile.
Barnette KG et al. Oral Sabizabulin for High-Risk, Hospitalized Adults with Covid-19: Interim Analysis New Eng J Med 2022