Synairgen stock climbs on COVID-19 treatment results

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Synairgen plans to run pivotal phases in hospital and home settings (Getty Images/Naeblys)

Synairgen has shared more data from the COVID-19 clinical trial that sent its stock up 300% earlier this year. The latest update, which triggered a 30% jump in Synairgen’s shares, contains a closer look at the effect of inhaled nebulised interferon beta-1a SNG001 on hospitalized COVID-19 patients.

In July, Synairgen said hospitalized COVID-19 patients who took SNG001 had a 79% lower chance of developing severe disease than their counterparts who got a placebo. The update lit a rocket under Synairgen’s share price, despite the fact the British biotech was yet to share data collected using the Ordinal Scale for Clinical Improvement (OSCI) that served as the primary endpoint of the phase 2.

Synairgen shared data on OSCI, an eight-point scale created by the World Health Organization, in September. The update linked SNG001 to an odds ratio for any improvement in OSCI at day 15/16 compared to the baseline of 2.32. The p-value was 0.033.

The latest updates, which were presented in The Lancet, include a more detailed look at the effect of SNG001 on OSCI. Seventy-five percent of patients on SNG001 had any improvement from baseline by day 15/16, compared to 70% in the placebo cohort.

That headline comparison masks details that offer encouragement to Synairgen. Around one-fifth of patients in the placebo cohort only went up one OSCI level from baseline, for example, because they went from requiring oxygen by mask or nasal prongs to being hospitalized but not requiring oxygen therapy. Only 14% of patients on placebo improved by three or more OSCI levels.

In contrast, 34% of patients on SNG001 improved by three or more OSCI levels. Just 6% of patients in the inhaled nebulised interferon beta-1a only improved by one OSCI level. A similar pattern is seen in the day 28 data, when an 11-percentage-point difference in the proportion of responders, in favor of  SNG001, masks a larger difference in the numbers of patients improving by three or more levels.

The differences translated into larger numbers of people on SNG001 being uninfected or having no limitation on their activities, the two lowest scores on the OSCI scale. By day 15/16, 22% of people on placebo were OSCI level zero or one, compared to 44% of patients on SNG001. The difference in the rates of patients discharged from the hospital was notably smaller. 

OSCI was new when Synairgen began the study. To support the exploration of the study, Synairgen assessed the outcome in multiple statistical analyses and reported them without hierarchy. That had some downsides.

“This approach introduces the issue of repeat analyses of this outcome, which requires consideration in the interpretation of the result and highlights the need for larger-scale, formal testing of a selected approach in the next phase of development,” researchers wrote in The Lancet paper.

Synairgen is yet to start a pivotal trial. Rather, the company expanded the phase 2 trial to include 120 patients in the home setting. Once the expansion is complete, Synairgen plans to run pivotal phases in hospital and home settings that enroll 100 to 300 patients per arm, depending on what it learns in the phase 2.