An orally administered, fixed dose combination of ASC 09 [see Adis Insight Drug profile800031712] and ritonavir [see Adis Insight Drug profile800004117] is being developed by Ascletis Pharmaceuticals for the treatment of COVID-2019 infections (pneumonia) and HIV infections. ASC 09 is a protease inhibitor that is reported to have high antiviral potency and a high genetic barrier to resistance. Ritonavir is a small molecule of CYP3A4 inhibitor. Clinical development is ongoing in China.
As of February 2020, Ascletis Pharmaceuticals is looking for partners for development of ASC 09/ritonavir (Ascletis Pharmaceuticals website, February 2020).
Key Development Milestones
In April 2020, Ascletis Pharma received IND approval from National Medical Products Administration (NMPA) for ASC0 9F (ASC09/ritonavir ifxed-dose combination) 
As of April 2020, phase II development of ASC0 9F was underway for treatment of HIV infections  (Ascletis Pharma pipeline, April 2020)
In February 2020, The Second Affiliated Hospital of Chongqing Medical University initiated phase II trial to evaluate safety and efficacy of ASC09/ritonavir tablets, lopinavir/ ritonavir (Kaletra) and umifenovir (Arbidol) tablets in combination with interferon aerosol in the treatment of COVID-2019 infections (ChiCTR2000029759). The randomised trial intends to enrol approximately 60 patients in China  .
In February 2020, The First Affiliated Hospital of Zhejiang University School of Medicine initiated an early phase I trial to compare the safety and efficacy of ASC 09/ritonavir and lopinavir/ritonavirin patients with COVID-2019 infections (ChiCTR2000029603). The randomised trial intends to enrol approximately 80 patients in China.