Cold agglutinin disease (CAD) is a complement-dependent disorder, with extravascular and intravascular hemolysis resulting from initial or terminal complement activation, respectively. We tested the efficacy and safety of eculizumab, an inhibitor of the terminal complement pathway. Treatment-requiring patients received 600 mg eculizumab weekly for 4 weeks, followed 1 week later by 900 mg every other week through week 26. The primary end point was the difference in the lactate dehydrogenase level between the first and the last day of therapy. Twelve patients with chronic CAD and 1 patient with an acute cold agglutinin syndrome were included. The median lactate dehydrogenase level decreased from 572 U/L (interquartile range [IQR], 534-685) to 334 U/L (IQR, 243-567; P = .0215), paralleled by an increase in hemoglobin from 9.35 g/dL (IQR, 8.80-10.80) to 10.15 g/dL (IQR, 9.00-11.35; P = .0391; Wilcoxon signed-rank test). Three patients maintained and 8 patients acquired transfusion independence, and 1 patient each showed a reduced or increased transfusion requirement, respectively (P = .0215; exact McNemar’s test). Patients with cold agglutinins with a thermal amplitude of 37°C tended to have less pronounced lactate dehydrogenase responses than patients with cold agglutinins with narrower thermal amplitudes. In the latter, responses were observed at lower serum levels of eculizumab than they were in the former. In contrast to hemolysis, cold-induced circulatory symptoms remained unaffected. In conclusion, eculizumab significantly reduced hemolysis and transfusion requirement in patients with CAD. Suppression of hemolysis caused by cold agglutinins with a wide thermal amplitude may require higher eculizumab doses than used here. The trial is registered with EudraCT (#2009-016966-97) and www.clinicaltrials.gov (#NCT01303952).

Eculizumab is indicated for the therapy of patients with symptomatic paroxysmal nocturnal hemoglobinuria (PNH). Due to inhibition of terminal complement cascade, patients on eculizumab are susceptible to Neisseria meningitidis infections. The two mainstays to reduce the risk of infection are vaccination and antibiotic prophylaxis. In this retrospective study, serologic response was analyzed after vaccination with a meningococcal vaccine in 23 PNH patients (median age 36 years; range 25 - 88 years; 15 males, 8 females) by measuring serum bactericidal assay (SBA) using rabbit complement (rSBA) titers against meningococcal serogroups A, C, W, and Y. Serologic protection was defined by an rSBA titer ≥1:8. Forty-three percent (10/23) were vaccinated more than once due to chronic eculizumab treatment. Overall serologic response for the meningococcal serogroups was A: 78% (18/23), C: 87% (20/23), W: 48% (11/23), and Y: 70% (16/23). No meningococcal infections have been observed. As immunological response to vaccines varies, the use of serologic response analyses is warranted. Re-vaccination with a tetravalent conjugate vaccine under eculizumab therapy every 3 years is essential or should be based on response rates. If meningococcal infection is suspected, standby therapy with ciprofloxacin and immediate medical evaluation are recommended. The novel vaccines covering serogroup B may even further reduce the risk for infection.

BACKGROUND: Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia characterized by hemagglutination and complement-mediated extra- and intravascular hemolysis. Conventional therapeutic approaches, such as corticosteroids, intravenous immunoglobulin G, alkylating agents or other immunosuppressive drugs, are largely ineffective, and the therapeutic efficacy of rituximab is limited. Successful treatment of a patient with CAD with the terminal complement inhibitor eculizumab reported by us previously (Röth et al., Blood 2009) prompted us to test this novel approach in a larger number of patients. PATIENTS and METHODS: We conducted a prospective, controlled, non-randomized, multicenter phase II trial with pre- and post-treatment comparison. Inclusion criteria were symptomatic cold agglutinin-mediated hemolysis with a serum lactate dehydrogenase (LDH) level ≥ 2 x upper limit of normal and a cold agglutinin titer > 64 at 4°C. Eculizumab was given by intravenous infusion at 600 mg weekly for 4 weeks, followed 1 week later by a 900 mg dose and then 900 mg every other week through week 26. Two weeks before the first dose patients received vaccination against N. meningitidis. The primary endpoint was LDH level, secondary endpoints included transfusion requirements, parameters of intravascular hemolysis, quality of life, 6-minute walk test (6MWT), circulatory symptoms and thrombosis. The analysis was performed in the intent-to-treat population. Missing data were replaced by carrying the last observation forward. The trial was registered at http://clinicaltrials.gov as NCT01303952. RESULTS: Between 2011 and 2014 13 treatment-naïve or pretreated patients with CAD were enrolled. The median age was 74 years (range: 64 - 80), with a male-to-female ratio of 3 to 10. After treatment with eculizumab the LDH decreased from a median pre-treatment level of 572 U/L (mean ± standard deviation: 670 ± 300 U/L) by an average of 56% to a median end-of-treatment level of 327 U/L (400 ± 279 U/L; p = 0.0215, Wilcoxon signed-rank test). This was accompanied by a reduction in transfusion requirement from a median of 4.0 red blood cell units per patient in the 12-month period preceding participation in the study to 0.0 units during treatment with eculizumab. In 9 patients, transfusion requirements decreased during eculizumab therapy, in 3 patients, transfusions were required neither before nor during the study, and in one patient, transfusion requirement deteriorated (p = 0.0215, Exact McNemar's test). The result of the 6MWT improved from a median of 358 m at baseline to a median of 420 m at the end of treatment (p = 0.078). Questionnaires for quality of life showed no significant changes. During the enrollment phase, 7 thromboembolic events including 1 pulmonary embolism were recorded in a total of 4 patients; by contrast, no thromboembolic events were observed during treatment with eculizumab. A total of 37 adverse events were reported of which one was considered as probably related to eculizumab (pneumonia, patient recovered). All in all, 57% of adverse events were classified as unrelated, 5% as unlikely to be related, 32% as possibly related, and 3% as probably related to treatment. There were 4 serious adverse events. CONCLUSIONS: Treatment with eculizumab was safe and well tolerated in patients with CAD. It resulted in a statistically significant reduction in hemolysis and transfusion requirements and appeared to have a favorable impact on thromboembolic complications. The results of this trial support the notion that terminal complement activation is a relevant mediator of erythrocyte destruction in CAD. Disclosures Röth: Alexion Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Geron: Research Funding. Off Label Use: Use of eculizumab in CAD. Bommer:Alexion Pharmaceuticals: Honoraria. Hüttmann:Celgene: Other: Travel support, Speakers Bureau; Takeda: Consultancy, Other: Travel support; Gilead: Consultancy; Amgen: Consultancy, Research Funding; Roche: Research Funding. Schrezenmeier:Alexion Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Dührsen:Amgen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding.

Conclusion In ravulizumab-treated PNH patients, IgG and IgG subclass levels which are regulated by the FcRn remained unaffected. Therefore, no treatment associated hypogammaglobulinemia is to be feared under chronic ravulizumab therapy.

Pregnancies in paroxysmal nocturnal hemoglobinuria (PNH) are associated with increased morbidity and mortality. Retrospective studies suggest that outcome has improved with the advent of the complement inhibitor eculizumab. To substantiate this assumption we analyzed the data from patients treated in our department since 2009. All patients were included in the International PNH registry and followed prospectively. We identified 16 pregnancies in 9 patients with classical PNH, and two pregnancies in two patients with aplastic anemia (AA)-PNH. In classical PNH, 13 pregnancies were supported by eculizumab. Breakthrough hemolysis occurred in six pregnancies, necessitating an increase in the biweekly eculizumab dose from 900 mg to 1,200-1,800 mg. Red blood cell transfusions were given in six and platelet transfusions in two pregnancies. A Budd-Chiari syndrome and cholecystitis complicated the course of two pregnancies. Four of 13 pregnancies supported by eculizumab ended in spontaneous abortion or stillbirth, and one was prematurely terminated because of fetal trisomy 21. None of the three pregnancies not supported by eculizumab had a successful outcome. Half the deliveries were preterm. None of the patients died, and, in all but one patient, the post-partum period was uneventful. Both pregnancies in patients with AA-PNH took a favorable course. Our results confirm low maternal mortality and frequent breakthrough hemolysis in pregnant PNH patients receiving eculizumab. Fetal mortality and the rate of preterm delivery were higher than reported previously, possibly related to the use of registry data that are likely to reduce the risk of publication and recall biases.