Pharmacokinetics, Pharmacodynamics, and Exposure-Response of Lanadelumab for Hereditary Angioedema

A quantitative systems pharmacology model of plasma kallikrein-kinin system dysregulation in hereditary angioedema

Hereditary angioedema (HAE) due to C1-inhibitor deficiency is a rare, debilitating, genetic disorder characterized by recurrent, unpredictable, attacks of edema. The clinical symptoms of HAE arise from excess bradykinin generation due to dysregulation of the plasma kallikrein-kinin system (KKS). A quantitative systems pharmacology (QSP) model that mechanistically describes the KKS and its role in HAE pathophysiology was developed based on HAE attacks being triggered by autoactivation of factor XII (FXII) to activated FXII (FXIIa), resulting in kallikrein production from prekallikrein. A base pharmacodynamic model was constructed and parameterized from literature data and ex vivo assays measuring inhibition of kallikrein activity in plasma of HAE patients or healthy volunteers who received lanadelumab. HAE attacks were simulated using a virtual patient population, with attacks recorded when systemic bradykinin levels exceeded 20 pM. The model was validated by comparing the simulations to observations from lanadelumab and plasma-derived C1-inhibitor clinical trials. The model was then applied to analyze the impact of nonadherence to a daily oral preventive therapy; simulations showed a correlation between the number of missed doses per month and reduced drug effectiveness. The impact of reducing lanadelumab dosing frequency from 300 mg every 2 weeks (Q2W) to every 4 weeks (Q4W) was also examined and showed that while attack rates with Q4W dosing were substantially reduced, the extent of reduction was greater with Q2W dosing. Overall, the QSP model showed good agreement with clinical data and could be used for hypothesis testing and outcome predictions.

Hereditary angioedema outcomes in US patients switched from injectable long-term prophylactic medication to oral berotralstat

BACKGROUND

Berotralstat, a first-line, once-daily, oral plasma kallikrein inhibitor for long-term prophylaxis of hereditary angioedema (HAE), is an effective and well-tolerated treatment option.

OBJECTIVE

To summarize the safety, effectiveness, and impact on treatment satisfaction in patients who switched from injectable long-term prophylactics to oral berotralstat monotherapy (150 mg daily) at US sites in the international open-label APeX-S study.

METHODS

APeX-S was an open-label, Phase II study of berotralstat conducted in 22 countries. Here, we focus on APeX-S patients enrolled at US sites who switched from injectable long-term prophylactics to berotralstat 150 mg once-daily monotherapy.

RESULTS

A total of 34 patients discontinued lanadelumab (n = 21), subcutaneous C1 esterase inhibitor (n = 11), or intravenous C1 esterase inhibitor (n = 2) and switched to berotralstat 150 mg monotherapy. Vomiting, diarrhea, and upper respiratory tract infection were the most common adverse events (each 11.8%). Mean monthly attack rates were consistently low after the switch to berotralstat. The mean (SEM) monthly attack rate was 0.29 (0.11) at Month 1, 0.48 (0.15) at Month 6, and 0.58 (0.23) at Month 12. The median attack rate was 0 attack/mo throughout 12 months of treatment. Improvements were observed in the Treatment Satisfaction Questionnaire for Medication from baseline to Month 12 after the switch to berotralstat monotherapy, with the greatest improvements in convenience.

CONCLUSION

The transition from injectable prophylactic medication to berotralstat was generally well tolerated. Patients switching to berotralstat monotherapy maintained good control of their HAE symptoms and reported improved treatment satisfaction.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03472040.

Lanadelumab in Patients 2 to Less Than 12 Years Old With Hereditary Angioedema: Results From the Phase 3 SPRING Study

BACKGROUND

Symptoms of hereditary angioedema (HAE) often first occur during childhood, and HAE attacks in children can be severe and substantially affect health-related quality of life (HRQoL). However, there are no approved long-term prophylaxis treatments for children aged less than 6 years.

OBJECTIVE

The SPRING Study (NCT04070326) evaluated the safety, pharmacokinetics, and efficacy of lanadelumab and HRQoL in patients aged 2 to less than 12 years.

METHODS

Over 52 weeks of treatment, patients aged 2 to less than 6 years received lanadelumab 150 mg every 4 weeks (Q4W) and patients aged 6 to less than 12 years received 150 mg every 2 weeks (Q2W) but could switch to Q4W if they were attack-free for 26 weeks.

RESULTS

We enrolled 21 patients (aged 2 to less than 6 years: n = 4; aged 6 to less than 12 years: n = 17), 20 of whom completed the study. There were no reported serious treatment-emergent adverse events or discontinuations resulting from such events. Treatment-emergent adverse events were reported for 17 patients (81.0%). The most common TEAE was injection site pain. Overall systemic exposure was comparable for both age groups. The mean (SD) attack rate during treatment decreased by 94.8% from baseline (1.84 [1.53] to 0.08 [0.17] attacks/mo), and 16 (76.2%) patients were attack-free. The attack rate reduction in both age groups was similar during the first 26-week fixed-dosing treatment. Seven patients switched from Q2W to Q4W and remained attack-free. A large, clinically meaningful increase in the Pediatric Quality of Life Inventory Generic Core Scale Total Score and a large increase in the Pediatric Quality of Life Inventory Generic Core Scale-Family Impact Module Total Score from baseline to end of study (better HRQoL) were observed.

CONCLUSIONS

Findings support safety, efficacy, and improved HRQoL with lanadelumab 150 mg Q2W and Q4W regimens for the prevention of HAE attacks in patients aged 2 to less than 12 years.

STAR-0215 is a Novel, Long-Acting Monoclonal Antibody Inhibitor of Plasma Kallikrein for the Potential Treatment of Hereditary Angioedema

Hereditary angioedema (HAE) is a rare autosomal dominant disorder caused by a deficiency in functional C1 esterase inhibitor, a serpin family protein that blocks the activity of plasma kallikrein. Insufficient inhibition of plasma kallikrein results in the overproduction of bradykinin, a vasoactive inflammatory mediator that produces both pain and unpredictable swelling during HAE attacks, with potentially life-threatening consequences. We describe the generation of STAR-0215, a humanized IgG1 antibody with a long circulating half-life (t1/2) that potently inhibits plasma kallikrein activity, with a >1000-fold lower affinity for prekallikrein and no measurable inhibitory activity against other serine proteases. The high specificity and inhibitory effect of STAR-0215 is demonstrated through a unique allosteric mechanism involving N-terminal catalytic domain binding, destabilization of the activation domain, and reversion of the active site to the inactive zymogen state. The YTE (M252Y/S254T/T256E) modified fragment crystallizable (Fc) domain of STAR-0215 enhances pH-dependent neonatal Fc receptor binding, resulting in a prolonged t1/2 in vivo (∼34 days in cynomolgus monkeys) compared with antibodies without this modification. A single subcutaneous dose of STAR-0215 (≥100 mg) was predicted to be active in patients for 3 months or longer, based on simulations using a minimal physiologically based pharmacokinetic model. These data indicate that STAR-0215, a highly potent and specific antibody against plasma kallikrein with extended t1/2, is a potential agent for long-term preventative HAE therapy administered every 3 months or less frequently. SIGNIFICANCE STATEMENT: STAR-0215 is a YTE-modified immunoglobulin G1 monoclonal antibody with a novel binding mechanism that specifically and potently inhibits the enzymatic activity of plasma kallikrein and prevents the generation of bradykinin. It has been designed to be a long-lasting prophylactic treatment to prevent attacks of HAE and to decrease the burden of disease and the burden of treatment for people with HAE.

Therapeutic monoclonal antibodies with a focus on hereditary angioedema

Monoclonal antibodies (mAbs) have been shown to be effective and generally safe across a continually expanding list of therapeutic areas. We describe the advantages and limitations of mAbs as a therapeutic option compared with small molecules. Specifically, we discuss a novel mAb in the treatment of hereditary angioedema (HAE), a rare and potentially life-threatening condition characterized by recurrent unpredictable swelling attacks. HAE is mediated by dysregulation of plasma kallikrein activity leading to overproduction of bradykinin. Current prophylactic treatment for HAE includes androgens or replacement of the endogenous plasma kallikrein inhibitor, C1 inhibitor. However, there remains an unmet need for an effective, less burdensome treatment option. Lanadelumab is a fully human mAb targeting plasma kallikrein. Results from clinical trials, including a pivotal Phase 3 study and its ensuing open-label extension study, demonstrated that lanadelumab is associated with few treatment-related adverse events and reduced the rate of HAE attacks. This novel treatment option has the potential to significantly improve the lives of patients with HAE.

What's New in the Treatment of Urticaria and Angioedema

Chronic urticaria and angioedema are diseases often managed by Allergy and Immunology specialists. Recent international guidelines have outlined a stepwise approach to management of patients using dose escalation of second-generation antihistamines followed by use of omalizumab and finally cyclosporine in more refractory cases. In select patients (those with refractory chronic urticaria), nonbiologic alternative medications with anti-inflammatory or immunosuppressant activity may be considered. Angioedema without wheals may have several different pathophysiologic mechanisms. Optimal management of mast cell-mediated angioedema is less clear but is often managed similar to chronic spontaneous urticaria. Drug-induced angioedema due to angiotensin-converting enzyme inhibitors is a common cause of angioedema in the emergency department. Although bradykinin is thought to be a primary mediator for this type of angioedema, studies of targeted therapies have been generally disappointing. In contrast, several targeted therapies have been proven successful using acute and preventive approaches for management of hereditary angioedema. Further developments, including novel biologics, novel oral therapies, and gene therapy approaches, may hopefully continue to broaden therapeutic options to ensure optimal individual management of patients with hereditary angioedema.