2026-07-12 | Sebetralstat for breakthrough attacks in patients with hereditary angioedema receiving long-term prophylaxis in KONFIDENT-S.
Although long-term prophylaxis (LTP) reduces attack frequency in hereditary angioedema, patients may experience breakthrough attacks. Oral sebetralstat demonstrated favorable safety and efficacy compared with placebo in the randomized phase 3 KONFIDENT trial (NCT05259917), including in patients receiving LTP. The safety and effectiveness of sebetralstat in participants receiving LTP are being assessed in the KONFIDENT-S open-label extension study (NCT05505916). This interim analysis of the KONFIDENT-S study evaluated long-term safety and effectiveness of oral sebetralstat 600 mg for attacks of hereditary angioedema with C1-inhibitor deficiency in participants receiving LTP with lanadelumab, berotralstat, or C1 inhibitor. Efficacy end points included times to beginning of symptom relief, reduction in severity, and complete attack resolution. As of September 14, 2024, 35 participants receiving LTP experienced a mean ± standard deviation of 1.7 ± 1.5 attacks per month and treated 382 attacks with sebetralstat (1.3 ± 1.1 sebetralstat-treated attacks per month). Median (interquartile range) time from attack recognition to sebetralstat administration was 6 (1-40) minutes; time to beginning of symptom relief was 1.3 (0.8 to 3.8) hours, time to reduction in severity was 4.2 (1.3 to >12) hours, and time to complete attack resolution was 14.8 (4.6 to >24) hours. Effectiveness was similar for participants receiving berotralstat, lanadelumab, or C1 inhibitor. No serious or severe treatment-related treatment-emergent adverse events were reported. Sebetralstat was well tolerated and enabled early on-demand treatment of attacks in patients with hereditary angioedema with C1-inhibitor deficiency receiving LTP. Treatment of breakthrough attacks with sebetralstat resulted in rapid symptom relief, reduction in attack severity, and complete attack resolution, regardless of LTP mechanism of action.
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2026-07-08 | Donidalorsen for the Treatment of Hereditary Angioedema: A Review of Clinical Studies.
Hereditary angioedema (HAE) is a rare disease characterized by recurrent attacks of severe tissue swelling caused by dysregulation of the kallikrein-kinin system. Donidalorsen is a triantennary N-acetyl galactosamine-conjugated antisense oligonucleotide designed to specifically and reversibly reduce plasma prekallikrein production by binding to plasma prekallikrein messenger RNA in the liver. This report reviews donidalorsen's mechanism of action and data on the pharmacodynamics, efficacy, patient-reported outcomes, and safety of donidalorsen from clinical trials in adolescent and adult participants. In a Phase 1 trial, subcutaneous (SC) administration of donidalorsen led to dose-dependent reductions in plasma prekallikrein concentrations. In a subsequent Phase 2, randomized, placebo-controlled study, donidalorsen 80 mg SC once every 4 weeks (Q4W) for 16 weeks resulted in a 90% mean reduction in monthly HAE attack rate vs placebo, which was sustained for up to 4 years in an open-label extension (OLE). In the Phase 3, randomized, placebo-controlled OASIS-HAE study, patients receiving donidalorsen 80 mg Q4W or once every 8 weeks (Q8W) experienced significant mean reductions in HAE attack rates vs placebo over Weeks 0 to 24 (Q4W: 81%; Q8W: 55%). Mean attack rates were reduced by 87% (Q4W) and 60% (Q8W) vs placebo over Weeks 4 to 24. Reductions in attack rate from OASIS-HAE baseline were sustained for up to 1 year in the OASISplus OLE (Q4W: 94%; Q8W: 95%). A notable study in the clinical program included a cohort of patients who switched from berotralstat, C1 inhibitor, or lanadelumab to donidalorsen for up to 1 year; mean attack rates were reduced by 68% vs baseline (on prior HAE prophylaxis). Donidalorsen treatment improved quality of life at all assessments. Across studies, donidalorsen had an acceptable safety and tolerability profile, with mostly mild to moderate adverse events reported. Overall, the clinical data are promising for donidalorsen as a long-term prophylactic medication for HAE.
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2026-07-07 | Living-Donor Kidney Transplantation Between Mother and Son With Clinically Confirmed Hereditary Angioedema.
Hereditary angioedema (HAE) is a rare autosomal dominant disorder resulting from SERPING1-related C1-inhibitor deficiency. Surgical stress and airway manipulation may precipitate life-threatening attacks. Experience with kidney transplantation in patients with HAE remains extremely limited. We describe a 19-year-old male with end-stage kidney disease secondary to congenital obstructive uropathy and nephrolithiasis, who underwent successful living-donor kidney transplantation from his mother, also diagnosed with HAE type I. Because danazol is unavailable in Argentina, both donor and recipient received compounded stanozolol 2 mg daily, starting 5 days preoperatively and continuing for 5 days postoperatively. Fresh frozen plasma (FFP, 10 mL/kg) was administered before extubation to raise C1-inhibitor levels, and icatibant was kept on standby for rescue. Neither donor nor recipient experienced perioperative angioedema. Both had uneventful recoveries, with the recipient maintaining stable graft function over 10 months of follow-up (latest serum creatinine 1.4 mg/dL). This report demonstrates that living-donor kidney transplantation between two individuals affected by HAE can be performed safely with individualized prophylaxis and multidisciplinary coordination.
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