Cyxone has announced results from a phase 2 study of Rabeximod in Covid-19 patients with moderate disease.

The primary endpoint, ultimately proposed by the FDA, was to document the difference of the proportion of subjects alive and free of respiratory failure at day 28 between placebo (standard of care treatment) and Rabeximod plus standard of care. The data analysis showed that almost all patients were alive and free of respiratory failure at day 28 in the different treatment arms. No statistical difference between treatment arms could be observed at day 28, thus this endpoint assessment did not reveal if Rabeximod has additional benefits over standard of care at day 28.

Secondary and exploratory endpoints will be analyzed to assess benefit of Rabeximod in Covid-19. Notably, no serious adverse events connected to Rabeximod treatment were observed and the drug candidate was well-tolerated in infected patients. Cyxone continues its prepararations for the phase 2b study of Rabeximod in the treatment of rheumatoid arthritis.

“Our current data analysis indicate that almost all patients received a treatment effect, however no statistically significant differences could be observed between the treatment groups and those who received placebo.”

”The top-line data from our study of Rabeximod in Covid-19 patients did not provide us with conclusive findings. Our current data analysis indicate that almost all patients received a treatment effect, however no statistically significant differences could be observed between the treatment groups and those who received placebo. We will now look further into the data to see if we can capture signals that are able to discriminate the groups better. Again, we can conclude that Rabeximod is safe and well tolerated in patients and does not increase the risk of developing severe disease,” explained Carl-Magnus Högerkorp, COO, Cyxone.

About the Phase 2 study

The phase 2 Covid-19 study included 92 patients. The intended inclusion criteria were patients diagnosed with Covid-19 who exhibited moderate symptoms (having difficulty breathing, signs of pneumonia, potentially requiring oxygen but not requiring mechanical ventilation). The patients were randomized to three arms, Rabeximod 15 mg o.d (n=30), 30 mg o.d (n=30) or placebo (n=32) and constituting two types of patients (with and without oxygen therapy), receiving treatment in an inpatient and outpatient fashion. The treatment period was 14 days, the endpoint 28 days and all patients were followed up for 60 days.

The primary endpoint in the study was to assess the proportion of subjects alive and free of respiratory failure (need for invasive mechanical ventilation, non-invasive ventilation, high-flow nasal cannula oxygen, or ECMO) at day 28 for the three arms. The study objective was to determine if there is a difference in the proportions of subjects that can be categorized as “alive and free of respiratory failure” in the different treatment arms in comparison to placebo (standard of care treatment such as dexamethasone). The U.S. Food and Drug Administration (FDA) has performed a pre-review of the statistical analysis plan prior to data unblinding.

The data analysis showed that 100% of the patients in the 30 mg arm were “alive and free of respiratory failure” 28 days following start of treatment. The corresponding proportions of patients in the 15 mg arm and in the placebo arms were 97% and 97%, respectively. The difference between the treatment arms and the placebo group were not statistically significant. Further, the study data concludes that treatment with Rabeximod did not increase the risk to develop more severe disease.

Next steps

As a next step, Cyxone will explore the secondary and exploratory endpoints in detail to gain further insights into the therapeutic effect of the drug candidate in Covid-19 and Rabeximod’s mode of action. These analyses will guide further strategic decisions concerning the next step for the program.

The company will also now intensify its efforts on evaluating the drug candidate in patients with rheumatoid arthritis and is currently preparing the initiation of a phase 2b study in this indication.

“As we continuously learn more about the virus and the disease we will be able to establish more precise treatments in the future, and given the great need for better treatments to combat the Covid-19 pandemic, our extended analysis of secondary endpoints will guide us on whether further development of Rabeximod is warranted in this indication. Nevertheless, the results reinforce the beneficial safety and tolerability profile of our drug candidate in infected and ill patients. We will now intensify our preparations for the upcoming phase 2b study of Rabeximod in patients with rheumatoid arthritis, where we look forward to start this program in 2022,” commented Tara Heitner, CEO, Cyxone.

Photo of Carl-Magnus Högerkorp, COO, Cyxone