Hereditary angioedema: a decade of human C1-inhibitor concentrate therapy

BACKGROUND

C1-inhibitor (C1-INH) is a serine protease inhibitor regulating the complement, kinin-kallikrein, coagulation, and fibrinolytic systems. Hereditary angioedema (HAE) is caused by an inherited deficiency of C1-INH characterized by sudden, recurrent edematous swellings of the subcutaneous or submucosal tissues. The optional therapy for the acute management of HAE is administration of human C1-INH (hC1-INH) concentrate. However, hC1-INH is not available in many countries, in which case fresh frozen plasma is an alternative.

OBJECTIVE

To summarize our experience with hC1-INH concentrate in patients with HAE.

METHODS

Clinical and laboratory information on the effectiveness and safety of hC1-INH administered to relieve 468 acute edematous attacks in 61 patients with HAE was analyzed.

RESULTS

Severe abdominal or subcutaneous attacks and laryngeal edema were consistently relieved by the administration of 500 U hC1-INH concentrate. Symptoms improved within 15 to 60 minutes of administration. Progression of the attacks was never observed, and there were no recurrent attacks within 72 hours. hC1-INH concentrate requirements did not change after repeated use. hC1-INH concentrate proved effective in the management of 94 attacks in 22 children and 6 attacks in 4 pregnant women. Adverse reactions, viral infections, and antibody formation against the purified protein did not occur.

CONCLUSION

The administration of hC1-INH concentrate in HAE is highly effective and safe for the treatment of acute attacks and short-term prophylaxis and in pediatric patients and pregnant women.

CLINICAL IMPLICATIONS

Human C1-INH concentrate is effective and safe for the treatment of acute HAE attacks as well as for short-term prophylaxis.

Beneficial effects of C1 esterase inhibitor in ST-elevation myocardial infarction in patients who underwent surgical reperfusion: a randomised double-blind study

BACKGROUND

The inflammatory cascade has been hypothesized to be an important mechanism of post-ischaemic myocardial reperfusion injury and several studies demonstrated that C1 esterase inhibitor (C1-INH) is effective in post-ischaemia myocardial protection. Therefore, we aimed to investigate prospectively in a randomised double-blind study the cardioprotective effects of C1-INH in ST segment elevation myocardial infarction (STEMI) in patients who underwent emergent reperfusion with coronary artery bypass grafting (CABG).

METHODS

In this study, we enrolled 80 patients affected with STEMI who underwent emergent CABG. Patients were assigned in two groups (C1-INH group: receive 1000 UI of C1-INH; and placebo group: receive a saline solution). The effects of C1-INH on complement inhibition, myocardial cell injury extension and clinical outcome were studied. Haemodynamic data and myocardial function were monitored. C1-INH, C3a, C4a complement activation fragments and cardiac troponin I (cTnI) serum levels were measured before, during and after surgery.

RESULTS

Patient characteristics were not different between the two groups. The overall in-hospital mortality rate was 6.2%. No statistical significant difference was observed between the two groups with regard to early mortality (p=0.36). Statistical significant difference between the two groups was showed for cardiopulmonary bypass support (p=0.04), administration of high dose of inotropes drugs (p=0.001), time of intubation (p=0.03), intensive care unit (ICU) stay (p=0.04) and in-hospital stay (p=0.03). A significant improvement in mean arterial pressure (p=0.03), cardiac index (p=0.02) and stroke volume (p=0.03) was showed in C1-INH group versus placebo group. The serum cTnI levels were significantly low in the C1-INH group versus placebo group after reperfusion, during the observation period. Plasma levels of C3a and C4a complement fragments were reduced significantly in C1-INH group. No drugs-related adverse effects were observed.

CONCLUSIONS

The inhibition of the classic complement pathway by C1-INH appears to be an effective mean of preserving ischaemic myocardium from reperfusion injury as demonstrated by low serum cTnI levels in C1-INH group. Therefore, the use of C1-INH during CABG as a rescue therapy in STEMI patients is probably an effective treatment to inhibit complement activity and to improve cardiac function and haemodynamic performance without impacting early mortality. Large randomised study should be performed to support our results.

C1-inhibitor in patients with severe sepsis and septic shock: beneficial effect on renal dysfunction

OBJECTIVE

To investigate the efficacy and the safety of the parenteral administration of C1-inhibitor to patients with severe sepsis or septic shock.

DESIGN

Double blind, randomized, and placebo-controlled trial.

SETTING

Surgical and medical intensive care units of a tertiary care university hospital.

PATIENTS

Forty consecutive patients (20 C1-inhibitor/20 placebo) who entered the intensive care unit with severe sepsis or septic shock.

INTERVENTION

C1-inhibitor intravenously in a 1-hr infusion, starting with 6000 IU, followed by 3000 IU, 2000 IU, and 1000 IU at 12-hr intervals, compared with placebo.

MEASUREMENTS AND MAIN RESULTS

C1-inhibitor administration significantly increased plasma C1-inhibitor antigen and activity levels during days 1-4 (p <.007). Patients in the C1-inhibitor group had significantly lower serum creatinine concentrations on day 3 (p =.048) and 4 (p =.01) than placebo patients. Multiple organ dysfunction assessed by logistic organ dysfunction and sepsis-related organ failure assessment scores was less pronounced in patients treated with C1-inhibitor. Mortality rate was similar in both groups. There were no C1-inhibitor-related side effects.

CONCLUSIONS

C1-inhibitor administration attenuated renal impairment in patients with severe sepsis or septic shock.

C1-inhibitor: an anti-inflammatory reagent with therapeutic potential

Excessive activation of the protein cascade systems often leads to severe inflammatory tissue destruction with potential life-threatening outcome. These include clinical disorders, such as capillary leak syndrome, septic shock, myocardial infarction and other ischaemia/reperfusion injuries, trauma, burns, multiple organ failure, as well as graft rejection. A therapeutic substitution of appropriate regulators appears to be a reasonable approach to reduce undesirable inflammatory reactions. C1-inhibitor, a multifunctional regulator of the various kinin-generating cascade systems, is frequently reduced in patients suffering from severe inflammation. C1-inhibitor concentrate has been used for decades as a substitution therapy to treat acute attacks in patients with hereditary angioedema. Studies including pathophysiologically relevant animal models now provide sufficient evidence that C1-inhibitor may also serve as an effective means to protect against inflammatory tissue injury. Promising clinical results are emerging which support C1-inhibitor as a candidate for therapy in severe inflammatory disorders. Although treatment with C1-inhibitor is regarded as safe, recent reports on possible side effects in certain clinical situations emphasise the importance of controlled clinical studies. The following review will focus on the impact of C1-inhibitor treatment on diseases, where complement contributes to the pathogenesis.

C1 esterase inhibitor: new preparation. A major advance in emergency treatment of hereditary angioneurotic oedema

(1) The reference prophylaxis of attacks of hereditary angioneurotic oedema is oral danazol, an androgenic steroid, which takes a few days to act. There was previously no curative treatment authorised in France. (2) C1 esterase inhibitor is now licensed in France as replacement therapy for patients with hereditary angioneurotic oedema due to a quantitative or qualitative deficiency in this protein. (3) The clinical evaluation file partly answers the practical questions that arise in this setting, but it does not include trials versus danazol. (4) In 36 patients with acute attacks of angioneurotic oedema, a double-blind trial showed that symptom relief was achieved in less than half an hour in 69% of attacks treated with C1 esterase inhibitor, compared to only 2% of attacks treated with placebo. (5) In the prophylactic setting, a crossover trial involving six patients refractory to conventional androgen therapy showed that injections of C1 esterase inhibitor every three days were more effective than a placebo in reducing the risk of attacks. (6) No major adverse effects have been attributed so far to C1 esterase inhibitor, but the fact that the drug is derived from human blood means that treatment carries a theoretical risk of infection by conventional infectious agents (especially nude viruses) and prions. (7) In practice, for life-threatening attacks of angioneurotic oedema, C1 esterase inhibitor is rapidly effective in two-thirds of patients and is now the reference treatment. In the absence of comparative trials, danazol remains the first-line prophylaxis when patients are scheduled for surgery a few days later, but C1 esterase inhibitor is useful when danazol is ineffective. C1 esterase inhibitor is the only available prophylaxis for patients undergoing emergency surgery (within a few hours).

A randomized, controlled trial to study the efficacy and safety of C1 inhibitor concentrate in treating hereditary angioedema

BACKGROUND

No effective treatment exists in the United States for acute attacks of hereditary angioedema (HAE).

STUDY DESIGN AND METHODS

To evaluate the efficacy and safety of C1 inhibitor concentrate in treating HAE, a large primary care and referral center hospital conducted a randomized, placebo-controlled, double-blind trial with intent-to-treat analysis. Of the 36 patients enrolled in the study, 23 received treatment, and 22 completed the trial. C1 inhibitor concentrate or albumin (placebo) infusions were administered in a blind fashion to HAE patients who came to the hospital for treatment no later than 5 hours after an attack began.

RESULTS

Relief was almost twice as fast in persons receiving C1 inhibitor concentrate than in the controls: 7.62 hours (mean; SD 7.08) versus 15.35 hours (mean; SD 8.31), respectively. The difference for time-to-relief was highly significant (p = 0.007, Mann-Whitney U test). The median time-to-relief was 6.17 hours (interquartile range 0.33-15.35) in the treatment group and 15.35 hours (interquartile range 14.00-22.83) in the control group. Resolution of symptoms was one-third faster in the C1 inhibitor concentrate group than in the placebo group: 23.98 hours (mean; SD 14.81) and 34.58 hours (mean; SD 13.56), respectively (p = 0.09, Mann-Whitney U test). Recovery of functional C1 inhibitor was 119.65 percent (mean; SD 50.80), and half-life was 37.87 hours (mean; SD 19.75). Recovery of antigenic C1 inhibitor was 147.75 percent (mean; SD 97.68), and half-life was 24.01 hours (mean; SD 9.70). There were no viral infections or serious adverse effects from the drug after 70 attacks in the treatment group and 96 attacks in the control group.

CONCLUSIONS

C1 inhibitor concentrate is a safe, effective treatment for acute attacks of HAE.

[Microcirculation and hemostasis in inflammatory processes. Modulation by administration of physiologic protease inhibitors as a therapeutic approach]

BACKGROUND

The course of an inflammatory process is based upon complex interactions between the vessel wall and the humoral or cellular compounds of the vascular content as a consequence of a defense reaction. There are no substantial differences between the pathophysiology of local or of whole body inflammation on the molecular and cellular level. Sepsis, which is clinically regarded as a systemic inflammatory process requires the broad therapeutical spectrum of nowaday intensive care medicine, but still has a high mortality. The pathophysiology and clinical examples for both systemic and local inflammatory reactions are presented in this paper. Thereby, similar interactions between the vascular endothelium, the mediator systems to which the hemostatic system has to be considered as a part of, and the microcirculation remain in the foreground at first. Based on that, the use of polyvalent protease inhibitors in the therapy of local or systemic inflammatory reactions of different origin will be discussed. The spotlight falls on physiological inhibitors of the hemostatic and complement system, antithrombin III and C1-esterase inhibitor, which may have a regulatory function within these systems because of their multiple targets.

CONCLUSION

The possibility of an adjuvant therapy of local or generalized inflammatory processes with physiologic protease inhibitors seems to be very promising. Nevertheless, at yet the substantial mechanisms of action are not fully understood.

[The use of a C1-inhibior concentrate for short-term preoperative prophylaxis in two patients with hereditary angioedema]

A commercially available C1 inhibitor (C1-INH) concentrate was used for short-term prophylaxis before surgery in two patients with hereditary angioneurotic oedema. The patients suffered from recurrent subcutaneous and submucosal oedema of the face, extremities, and gastrointestinal tract as the result of a hereditary C1-INH deficiency. Both patients were receiving tranexamic acid or danazol therapy as oral long-term prophylaxis. Over the years the patients underwent several operations in regional and general anaesthesia, with mask ventilation or intubation. The C1-INH plasma concentrations measured preoperatively were always very low (0.02-0.06 g/l, normal range 0.15-0.35 g/l), despite the oral long-term prophylaxis. Substitution treatment with 500-1000 U C1-INH was performed 1 h before surgery. No side effects were seen following the concentrate infusions. With this substitution treatment no specific symptoms of hereditary angioneurotic oedema were recognized in either case. The measurement of C1-INH plasma concentration 2 h or 4 h after C1-INH substitution showed a marked rise in both patients, though normal values were not reached in either. We suggest that infusion of C1 concentrate is an appropriate form of preoperative substitution treatment in patients with hereditary angioneurotic oedema, in view of the lower risk of infection than with infusion of fresh-frozen plasma and the observed effectiveness.