As of 31 March, the likelihood of approval (LoA) for Ionis Pharmaceuticals’ IONIS-PKK-LRx (donidalorsen sodium) for hereditary angioedema (HAE) rose 8 points in the aftermath of positive topline Phase II results, according to GlobalData’s LoA data.

The 20-patient Phase II met its primary endpoint of reduction in monthly HAE attacks, with a 90% mean reduction in weeks 1-17 (p<0.001) and a 97% mean reduction in weeks 5-17 (p=0.003), according to a 29 March company press release. The majority of adverse events (AEs) were mild, with the most common treatment emergent AE being headache and nausea, which occurred more frequently in the placebo group. Enrolled patients received a monthly subcutaneous injection of donidalorsen sodium (n=14) or placebo (n=6) for 17 weeks.

While the LoA prior to this news was 27%, GlobalData’s analysis using a combination of machine learning and a proprietary algorithm has raised the LoA to 35%. Donidalorsen sodium inhibits prekallikrein, leading to a reduction in bradykinin generation implicated in HAE attacks. This publication reported 16 March that donidalorsen sodium would likely demonstrate strong safety and similar efficacy to inhibitors targeting kallikrein, the active form of prekallikrein. Potential future competitors in the HAE space include kallikrein inhibitors Takeda’s monoclonal antibody Takhzyro (lanadelumab-fly) and BioCryst Pharmaceuticals’ small molecule Orladeyo (berotralstat), which received FDA approval in August 2018 and December 2020, respectively.

Ionis has a market cap of $6.6bn.

William Newton is a Healthcare Reporter for Clinical Trials Arena parent company GlobalData’s investigative journalism team. A version of this article originally appeared on the Insights module of GlobalData’s Pharmaceutical Intelligence Center. To access more articles like this, visit GlobalData.