Aptevo’s Ixinity Found Safe, Effective in Kids Under 12 with Hemophilia B, Trial Shows

Ixinity (recombinant factor IX product, IB1001) was found to be safe and effective in previously treated children with hemophilia B younger than 12, according to data from Aptevo Therapeutics‘ ongoing Phase 3 clinical trial.

The company presented data from the analysis of two studies at the recent Hemostasis and Thrombosis Research Society 2017 Scientific Symposium April 6-8 in Scottsdale, Arizona.

Ixinity is currently approved for the treatment of hemophilia B in patients 12 and older. The two studies followed 12 children younger than age 12 over time. The participants could either be treated with prophylactic (preventive) or on-demand infusions. The child’s physician determined which type of treatment was suitable.

Nearly all (11 of the 12) patients received prophylactic treatment. In this group, the median number of bleeding episodes was 1.0, and the median annualized bleeding rate was 0.3.

The effectiveness of Ixinity to control bleeding was evaluated using annualized bleeding rates, the number of infusions needed to stop a bleeding episode, and a subjective rating of how efficient the bleeding control was in a patient’s opinion.

In total, the participants experienced 61 bleeding episodes, of which 10 percent were handled without treatment, 72 percent were resolved after one Ixinity infusion, 8 percent were resolved after two infusions, and 10 percent required three, four, or five infusions of the clotting factor.

Patients rated a total of 34 bleeding episodes, and stated that the treatment was linked to “excellent” bleeding control in 65 percent of events, “good” in 32 percent of the episodes, and “fair” in 3 percent of the bleeding episodes. No episodes were linked to a “poor” bleeding control.

“We’re encouraged to see data in a pediatric setting demonstrating the safety and efficacy of Ixinity in this important population,” Scott Stromatt, Aptevo’s senior vice president and chief medical officer, said in a press release.

“The key efficacy outcomes from this study are comparable to what has previously been demonstrated in our pivotal study of Ixinity, which formed the basis for our licensure in the United States in patients age 12 or older,” he said. “In this pooled analysis, Ixinity was well tolerated and effective in preventing and controlling bleeding episodes in previously treated patients under the age of 12 with hemophilia B.”

Two patients showed side effects of the treatment during the studies. One developed excessive sweating (hyperhidrosis) and fever, and another patient experienced only excessive sweating. It is possible that patients who receive recombinant factor IX develop inhibitors to the treatment. This was not seen in any patient in the study.

“As patients are known to respond to different factor IX options differently, Ixinity offers people with hemophilia B another option to dose strategically to prevent and control bleeding episodes,” Stromatt said. “We see value in having a variety of options available for patients and look forward to building on the data set in a pediatric setting to support a label expansion for Ixinity in patients under 12 years of age.”