Covid-19 (Rabeximod)

Covid-19 can cause widespread inflammation in the lungs, resulting in reduced oxygen levels in the blood. In severely affected patients the immune system overreacts, triggering an intense release of cytokines and chemokines that leads to hyperinflammation and severe respiratory failure.

Dexamethasone (a corticosteroid) and remdesivir (an antiviral agent) are used with some success, but there is a great need for better treatments. Antibody drug cocktails are also emerging which may possess similar ability to block multiple cytokines but requiring an infusion or injection.

Unlike dexamethasone and remdesivir, Cyxone’s drug candidate Rabeximod selectively targets the hyperactivated macrophage to suppress it. Importantly it does so without suppressing the general immune system. The macrophage is the central orchestrator of the inflammatory response in the lung causing a cytokine storm that results in a serious reduction of oxygen uptake in the lung, eventually leading to sepsis and general organ failure. Rabeximod inhibits the release of multiple cytokines. Inhibition of multiple cytokines rather than singe cytokines is expected to yield better efficacy in Covid-19.

In the case of acute respiratory disorders, the overreaction of the immune system can progress rapidly to an acute stage – ARDS, but it may be possible to prevent this progression if treated early. The favorable tolerability and safety profile of Rabeximod as well as its oral formulation make it a suitable therapy for patients with moderate Covid-19 disease severity.

Phase 1
Phase 2
Phase 3

Project status and next steps

  • A Phase 2 study has been conducted during 2021. Approximately 90 hospitalized patients with moderate Covid-19 disease were included in this randomized, placebo-controlled and double-blinded study to investigate the efficacy and safety of treatment with Rabeximod.
  • Cyxone has acquired exclusive rights to the patent applications covering the use of Rabeximod in this indication from the US based researcher and entrepreneur, Dr Kalev Kask.
  • A successful outcome of the Phase 2 study would open a range of opportunities for Rabeximod in Covid-19 and other virally induced acute respiratory disorders. The great medical need improves Cyxone’s chances of attracting a powerful partner to take on the future development and potential commercialization of Rabeximod in this indication.

It is worth noting that clinical trials in Covid-19 patients and in RA are not interdependent. Should the endpoint not be met in the Covid-19 trial, it would not affect the development of Rabeximod as a treatment of rheumatoid arthritis. The treatment duration as well as the underlying cause of the two diseases differ substantially.