Successful pregnancy outcome in paroxysmal nocturnal hemoglobinuria (PNH) following escalated eculizumab dosing to control breakthrough hemolysis

Eculizumab for paroxysmal nocturnal hemoglobinuria: Two cases of successful pregnancy outcomes

Paroxysmal nocturnal hemoglobinuria is a rare disease with the incidence ranging from 0.08 to 0.57 per 100,000 person-years. Up to 25% of cases in women are detected during pregnancy. We report two cases of successful pregnancy outcomes in patients treated with eculizumab, pointing out the importance of interdisciplinary approach in these high-risk pregnancies.

Pharmacokinetics of Monoclonal Antibodies Throughout Pregnancy: A Systematic Literature Review

BACKGROUND AND OBJECTIVE

Although little information is available on the pharmacokinetics (PK) of monoclonal antibodies (mAbs) during pregnancy, multiple mAbs are being used during pregnancy for various indications. The aim of this systematic literature review was to characterize the PK of mAbs throughout pregnancy.

METHODS

A systematic literature search was carried out in PubMed and Embase on 21 April 2023. Articles were included when information on PK or exposure parameters of mAbs in pregnant women was available.

RESULTS

A total of 42 relevant articles were included, of which eight discussed adalimumab, three certolizumab pegol, five eculizumab, one golimumab, 12 infliximab (IFX), two natalizumab, one canakinumab, one omalizumab, five tocilizumab, eight ustekinumab, and five vedolizumab. One of the 42 studies reported information on clearance (CL) and volume of distribution (VD) of IFX; all other studies only reported on serum concentrations in the pre-pregnancy state, different trimesters, and the postpartum period. For all of the assessed mAbs except IFX, serum concentrations were similar to concentrations in the pre-pregnancy state or modestly decreased. In contrast, IFX trough concentrations generally increased in the second and third trimesters in comparison to the non-pregnant state.

CONCLUSION

Available information suggests that the anatomical and physiological changes throughout pregnancy may have meaningful effects on the PK of mAbs. For most mAbs (not IFX), modestly higher dosing (per mg) maybe needed during pregnancy to sustain a similar serum exposure compared to pre-pregnancy.

Pregnancy with Paroxysmal Nocturnal Hemoglobinuria: A Case Series with Review of the Literature

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematopoietic stem cell disorder, and eculizumab and ravulizumab are its two approved therapies. Only few case series/reports have reported the outcomes of pregnancies in patients with PNH despite the increased risk of thrombosis. Similarly, there is limited knowledge regarding the effect of the approved treatments on conception and pregnancy outcomes. Here, we report the first series of pregnancies in PNH patients from the Middle Eastern region from our tertiary care hospital. Ten pregnancies in four females after diagnosis with PNH were identified. In terms of PNH management, only eculizumab was used, as the safety of ravulizumab use in pregnancies has not yet been established. In the antepartum period, the patients had variable symptoms that ranged from mild symptoms including epistaxis, tea-colored urine and vaginal bleeding to life-threatening vessel thrombosis. Further, red blood cell and platelet transfusions were required because of bleeding and hemolysis in four pregnancies. The pregnancy outcomes varied, but based on these, the safety of eculizumab use during pregnancy remained inconclusive. The postpartum period was complicated in one case by portal vein thrombosis and was managed accordingly. In conclusion, pregnant females with PNH are at an increased risk for complications due to PNH, and thus experienced hematologists and obstetricians should be involved jointly in their care.

Characterization of breakthrough hemolysis events observed in the phase 3 randomized studies of ravulizumab versus eculizumab in adults with paroxysmal nocturnal hemoglobinuria

Eculizumab is first-line treatment for paroxysmal nocturnal hemoglobinuria (PNH); however, approximately 11-27% of patients may experience breakthrough hemolysis (BTH) on approved doses of eculizumab. Ravulizumab, a new long-acting C5 inhibitor with a four times longer mean half-life than eculizumab, provides immediate, complete, and sustained C5 inhibition over 8-week dosing intervals. In two phase III studies, ravulizumab was non-inferior to eculizumab (Pinf ≤0.0004) for the BTH endpoint; fewer patients experienced BTH with ravulizumab versus eculizumab in both studies (301 [complement inhibitor−naïve patients], 4.0% vs. 10.7%; 302 [patients stabilized on eculizumab at baseline], 0% vs. 5.1%). In the current analysis, patientlevel data were evaluated to assess causes and clinical parameters associated with incidents of BTH reported during the 26-week treatment periods in the ravulizumab phase III PNH studies. Of the five BTH events occurring in ravulizumab-treated patients across the studies, none were temporally associated with suboptimal C5 inhibition (free C5 ≥0.5 mg/mL); four (80%) were temporally associated with complement-amplifying conditions (CAC). Of the 22 events occurring in eculizumab-treated patients, 11 were temporally associated with suboptimal C5 inhibition, including three events also associated with concomitant infection. Six events were associated with CAC only. Five events were unrelated to free C5 elevation or reported CAC. These results suggest that the immediate, complete, and sustained C5 inhibition achieved through weight-based dosing of ravulizumab reduces the risk of BTH by eliminating BTH associated with suboptimal C5 inhibition in patients with PNH. (Registered at clinicaltrials.gov identifiers: Study 301, NCT02946463; Study 302, NCT03056040.)

Update on Thrombocytopenia in Pregnancy

Thrombocytopenia, defined as platelet count < 150,000 mm³, is frequently diagnosed by obstetricians since this parameter is included in routine surveillance during pregnancy, with an incidence of between 7 and 12%. Therefore, decisions regarding subsequent examination and management are primordial. While most of the cases are due to physiological changes, as gestational thrombocytopenia, other causes can be related to severe conditions that can lead to fetal or maternal death. Differentiating these conditions might be challenging: they can be pregnancy-specific (pre-eclampsia/HELLP syndrome [hemolysis, elevated liver enzymes, low platelets]), or not (immune thrombocytopenia purpura, thrombotic thrombocytopenic purpura or hemolytic uremic syndrome). Understanding the mechanisms and recognition of symptoms and signs is essential to decide an adequate line of investigation. The severity of thrombocytopenia, its etiology and gestational age dictates different treatment regimens.

Assessing Preferences for Rare Disease Treatment: Qualitative Development of the Paroxysmal Nocturnal Hemoglobinuria Patient Preference Questionnaire (PNH-PPQ©)

PURPOSE

To develop a patient preference questionnaire (PPQ) assessing eculizumab and ravulizumab treatment for paroxysmal nocturnal hemoglobinuria (PNH).

PATIENTS AND METHODS

The development of the PNH-PPQ© was consistent with Food and Drug Administration guidelines for patient-reported outcome measure development, and included 1) a targeted literature review; 2) PNH expert clinician input on treatment preferences; 3) review of existing qualitative data on the PNH treatment and disease experience; 4) concept elicitation interviews with 8 PNH patients who received eculizumab and/or ravulizumab; 5) translatability review; and 6) cognitive debriefing with 5 patients. Interview participants were recruited through a United Kingdom PNH patient advocacy group and a Canadian clinical site involved in clinical trial ALXN1210-PNH-302.

RESULTS

Six themes were identified as most relevant to the PNH treatment experience from the concept elicitation interviews: disease symptoms (n=8/8); treatment frequency (n=7/8); quality of life impact of treatment/disease (n=7/8); treatment burden (n=7/8); treatment efficacy (n=5/8); and treatment side effects (n=5/8). An initial list of 88 preference questions was reduced to 11 highly relevant and non-redundant questions reflecting the 6 themes. Cognitive interview participants unanimously agreed that the PNH-PPQ instructions were clear; response options were understandable, easy to use, and provided enough choices; and the questions captured the factors that inform treatment preferences.

DISCUSSION

When new drugs have similar efficacy to existing medications, documenting patient preferences is important for confirming patient benefit from the new medication. Understanding what matters most to patients is essential for delivering patient-centered care and may play a particularly significant role in treatment decision making. The availability of such a tool may be especially important as new orphan drugs are developed and patients with rare diseases have more than one treatment option to consider.

CONCLUSION

The PNH-PPQ provides a patient-centered approach for evaluating preferences for the treatment of PNH. The PNH-PPQ has subsequently assessed patient preference in the clinical trial sub-study ALXN1210-PNH-302s.

Preoperative administration of eculizumab to prevent surgery-triggered hemolysis during cesarean section with paroxysmal nocturnal hemoglobinuria

Eculizumab in pregnancy has been reported to be effective in improving outcomes in patients with paroxysmal nocturnal hemoglobinuria. However, a cesarean section may result in surgery-triggered hemolysis. An additional dose of eculizumab just prior to delivery is an appropriate choice to prevent postoperative hemolysis.

Eculizumab in pregnancy: a narrative overview

Pregnancy can be a dangerous trigger for patients with paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), or hemolysis, elevated liver enzymes and low platelet (HELLP) syndrome. Due to the possibility of several serious complications, pregnancy is somewhat discouraged in the presence of the above diseases. Eculizumab is a humanized antibody that may dramatically change the clinical course of PNH, aHUS and HELLP syndrome. However, data on the safety of eculizumab in pregnancy are scarce. In this narrative overview, we summarize current evidence on the use of eculizumab during pregnancy in women with PNH, aHUS and HELLP syndrome. Eculizumab is not present in breast milk, and the levels observed in umbilical cord blood samples are not sufficient to affect the concentrations of complement in newborns. Therefore, eculizumab may be regarded as safe in pregnancy. Nonetheless, given that data on eculizumab in pregnancy are limited, it is not possible to completely exclude risks for both mother and fetus in treating PNH, aHUS and HELLP syndrome.

Eculizumab application during pregnancy in a patient with paroxysmal nocturnal hemoglobinuria: A case report with review of the literature

Eculizumab is highly effective in inhibiting complement activation and has successfully shown to prevent complications and to improve quality of life in patients with paroxysmal nocturnal hemoglobinuria (PNH). Its application during pregnancy showed favorable fetal and maternal outcome in the presented case and has proven to be effective without raising safety concerns.

Aplastic anemia during pregnancy: a review of obstetric and anesthetic considerations

Aplastic anemia is a hematologic condition occasionally presenting during pregnancy. This pathological process is associated with significant maternal and neonatal morbidity and mortality. Obstetric and anesthetic management is challenging, and treatment requires a coordinated effort by an interdisciplinary team, in order to provide safe care to these patients. In this review, we describe the current state of the literature as it applies to the complexity of aplastic anemia in pregnancy, focusing on pathophysiologic aspects of the disease in pregnancy, as well as relevant obstetric and anesthetic considerations necessary to treat this challenging problem. A multidisciplinary-team approach to the management of aplastic anemia in pregnancy is necessary to coordinate prenatal care, optimize maternofetal outcomes, and plan peripartum interventions. Conservative transfusion management is critical to prevent alloimmunization. Although a safe threshold-platelet count for neuraxial anesthesia has not been established, selection of anesthetic technique must be evaluated on a case-to-case basis.

Paroxysmal Nocturnal Hemoglobinuria in Pregnancy: A Dilemma in Treatment and Thromboprophylaxis

Paroxysmal nocturnal hemoglobinuria (PNH) is a hematologic disorder characterized by an acquired somatic mutation in the phosphatidylinositol glycan class A gene which leads to a higher risk for increased venous and arterial thrombosis. Current treatment for PNH includes eculizumab. Pregnant patients who have PNH have higher risk for thrombosis and hemorrhage with both pregnancy and their underlying PNH. Treatment frequently poses conundrum. The safety and efficacy of eculizumab during pregnancy and breast feeding have not been extensively studied and contraception has been recommended due to potential for teratogenicity. We present a case of a patient who was safely on both eculizumab and modest prophylactic anticoagulation for 6 weeks post-partum.

Eculizumab in the management of paroxysmal nocturnal hemoglobinuria: patient selection and special considerations

Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal disorder resulting from somatic mutation in the PIG-A gene leading to a deficiency of the membrane-anchoring molecule glycosylphosphatidylinositol. The lack of expression of two glycosylphosphatidylinositol-anchored proteins involved in the regulation of the complement system renders PNH erythrocytes susceptible to complement-mediated lysis. Clinical manifestations include thromboembolic disease, chronic kidney injury, pulmonary hypertension, smooth muscle dysfunction, and chronic hemolysis. Until recently, treatment was mainly supportive with most patients suffering from significant morbidity and shortened survival compared to age-matched controls. The development of eculizumab, a humanized monoclonal antibody directed against the terminal complement protein C5, has resulted in dramatic improvements of survival and reduction in complications. In this paper, we review some special considerations pertaining to the use of eculizumab for PNH.

Thrombocytopenia in Pregnancy

Thrombocytopenia, defined as blood platelet count below 150,000/ìL is the second leading cause of blood disorders in pregnancy after anemia. Gestational thrombocytopenia explains 70-80% of all cases of thrombocytopenia in pregnancy. Hypertensive disorders account for approximately 20% and immune thrombocytopenic purpura for about 3-4%. Other etiologies are considered rare in pregnancy. The aim of this study is to review the specific causes of thrombocytopenia in pregnancy, their obstetrical implications and management.

Pregnancy outcomes of patients with paroxysmal nocturnal hemoglobinuria treated with eculizumab: a Japanese experience and updated review

Pregnancy with paroxysmal nocturnal hemoglobinuria (PNH) is associated with significant risk of complications, such as life-threatening thrombosis. Recently, eculizumab has come into clinical use and revolutionized the treatment of PNH. However, clinical information regarding eculizumab use for PNH during pregnancy is limited. The present report describes pregnancies with PNH treated with eculizumab that were registered with the Japan PNH study group and reviews the literature. In case 1, the patient received eculizumab throughout pregnancy and delivered a healthy neonate at term, although breakthrough hemolysis occurred at 20 weeks of gestation. In case 2, the patient discontinued eculizumab before pregnancy and developed preeclampsia at 27 weeks of gestation. She received eculizumab and delivered a preterm, but healthy, neonate by cesarean section. In case 3, the patient received eculizumab from 18 weeks of gestation and delivered a healthy neonate at term without any complications. Reports of 11 pregnant women treated with eculizumab were identified in the literature. Of 14 pregnancies, including our own cases, breakthrough hemolysis and preeclampsia occurred in five and two cases, respectively. There were no thrombotic complications, maternal or neonatal deaths, or fetal structural abnormalities. Thus, eculizumab appears to be safe and effective for managing PNH during pregnancy.