A new study evaluating a recombinant factor VIII agent called SCT800 (omfiloctocog alfa) suggests long-term safety with this agent in patients with severe hemophilia A, in addition to maintenance of lower annualized bleeding rates (ABRs) in these patients. Results of the study were presented in a poster at the EHA 2022 Hybrid Congress by Feng Xue, MD, of the Chinese Academy of Medical Sciences and Peking Union Medical College in Tianjin, China, and colleagues.
Dr Xue and colleagues presented interim results from an extension study (ClinicalTrials.gov Identifier: NCT03947567), following an earlier pivotal study with this agent (ClinicalTrials.gov Identifier: NCT03815318). Included patients were at least 12 years of age, had severe hemophilia A, and had been previously treated.
The extension analysis was an open-label study evaluating long-term safety and efficacy with SCT800. In the extension analysis, patients who had completed the original trial continued to be treated with 25 to 50 IU/kg of SCT800 at a rate of either every other day or 3 times per week. The primary end point was inhibitor development, with median ABR as a key secondary end point.
This interim analysis of the extension study included 69 enrolled patients, while the pivotal study included 73 patients. Dr Xue and colleagues reported that by February 24, 2022, no patients had inhibitors detected, and this was after a median exposure time of 332 days (range, 79-432).
In the interim analysis of the extension study, the median ABR for all bleeds was 0.48 (interquartile range [IQR], 1.46), and the median ABR during the pivotal study had been 2.00 (IQR, 4.10). There were 178 total bleeds reported for the interim analysis of the extension study, and “excellent” or “good” hemostatic efficacy was reported for 88.8% of these bleeds. A total of 67 of the patients reportedly showed improved joint function, with a decrease of 3.4 points in the mean total Hemophilia Joint Health Score.
The median ABR for spontaneous bleeds was 0.00 (IQR, 0.87) in the interim analysis of the extension study, and it was 0.00 (IQR, 2.10) in the pivotal study. The median ABR for traumatic bleeds was 0.00 (IQR, 0.51) in this report of the extension study, and it was 0.00 (IQR, 2.10) in the pivotal study. The median ABR for joint bleeds was 0.48 (IQR, 1.30) in this report of the extension study, compared with 0.00 (IQR, 2.10) in the pivotal study.
The researchers reported that a total of 4 patients, or 5.8% of the population, experienced serious adverse events.
Dr Xue and colleagues concluded that this interim analysis of the extension study evaluating SCT800 in this population suggested favorable long-term safety, in addition to supporting maintenance of low ABRs in these patients.
Disclosures are not available for this presentation.
Xue F, Zhao X, Sun J, et al. Long term safety and efficacy of recombinant human coagulation factor VIII (SCT800) in previously treated patients with severe hemophilia A. Presented at EHA 2022; June 9-12, 2022. Abstract P1670.