Apellis Pharmaceuticals announced the company will not pursue additional development of APL-9, an investigational targeted C3 therapy designed for acute interventions, for the treatment of severe COVID-19. The decision followed an interim review of mortality data from the Phase 1/2 study by an independent data monitoring committee (DMC), which found no meaningful reduction in the overall mortality rate in patients treated with APL-9 in combination with standard of care therapy compared to standard of care alone. No safety signals were observed by the DMC.

“We initiated the clinical development of APL-9 in patients with severe COVID-19 because we believed that complement dysregulation may play a key role in disease mortality. We felt a responsibility to learn if controlling complement could help save lives during this devastating pandemic,” said Lukas Scheibler, Ph.D., chief innovation officer at Apellis. “While the mortality results from this study were not what we had hoped, we extend our heartfelt thanks to the patients and their families, healthcare providers, and investigators who joined us in working to address an urgent public health need. We remain confident in the potential of targeting C3 for complement-driven diseases and are committed to bringing transformative treatments to patients.”

No additional endpoints were analyzed as part of the interim review by the DMC. Enrollment is complete, and the study reached the last patient visit. Apellis plans to provide full results in a scientific forum following completion of the full data analysis.

APL-9 is an investigational drug designed to control the complement cascade centrally at C3 and may have the potential to treat a range of diseases caused by excessive or uncontrolled activation of complement. APL-9 leverages the same mechanism of action as Apellis’ lead compound, pegcetacoplan (APL-2), but has a lower molecular weight and shorter half-life. APL-9 is designed to be intravenously administered for acute use.