Actemra is widely used as a treatment for rheumatoid arthritis, but has seen a new lease of life as a COVID-19 treatment, with so much demand during the pandemic that it has outstripped supply.

Roche's Actemra has been in high demand since its value in treating severe COVID-19 was established, leading to shortages. Now, Sanofi's rival therapy Kevzara has also been hit by supply constraints.