Placental passage of eculizumab and complement blockade in a newborn

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.

Neuroimmunological Disorders

Multiple sclerosis is a disease that tends to affect women during their childbearing years. Although relapse risk decreases during pregnancy, patients should still be optimized on disease-modifying therapy before and after pregnancy to minimize gaps in treatment. Exclusive breastfeeding may reduce the chances of disease relapse postpartum, and many disease-modifying therapies are considered to be safe while breastfeeding. Treatments for other neuroimmunologic disorders such as neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody-associated disease, neurosarcoidosis, and central nervous system vasculitis may require rituximab before and prednisone or intravenous immunoglobulin therapy during pregnancy.

Differentiating and Managing Rare Thrombotic Microangiopathies During Pregnancy and Postpartum

The most common thrombotic microangiopathy (TMA) of pregnancy is the well-recognized syndrome of preeclampsia with hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. However, rare TMAs, including thrombotic thrombocytopenic purpura, complement-mediated hemolytic-uremic syndrome, and catastrophic antiphospholipid syndrome, may occur during pregnancy or postpartum and present with features similar to those of preeclampsia with severe features. Early recognition and treatment of these infrequently encountered conditions are key for avoiding serious maternal morbidities with long-term sequelae and possible maternal or fetal death. Differentiating between preeclampsia with severe features and these rare TMAs is diagnostically challenging as there is significant overlap in their clinical and laboratory presentation. Given the rarity of these TMAs, high-quality evidence-based recommendations on diagnosis and management during pregnancy are lacking. Using current objective information and recommendations from working groups, this report provides practical clinical approaches to diagnose and manage these rare TMAs. This report also discusses how to manage individuals with a history of these rare TMAs who are planning to conceive. To optimize favorable outcomes, a multidisciplinary approach including obstetricians, maternal-fetal medicine specialists, hematologists, and nephrologists alongside close clinical and laboratory monitoring is vital.

A Guide for Adult Nephrologists and Hematologists to Managing Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy in Teens Transitioning to Young Adults

Atypical hemolytic uremic syndrome and C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis are ultra-rare chronic, complement-mediated diseases with childhood manifestation in a majority of cases. Transition of clinical care of patients from pediatric to adult nephrologists-typically with controlled disease in native or transplant kidneys in case of atypical hemolytic uremic syndrome and often with chronic progressive disease despite treatment efforts in case of C3 glomerulopathy/immune complex membranoproliferative glomerulonephritis-identifies a challenging juncture in the journey of these patients. Raising awareness for the vulnerability of this patient cohort; providing education on disease pathophysiology and management including the use of new, high-precision complement antagonists; and establishing an ongoing dialog of patients, families, and all members of the health care team involved on either side of the age divide will be inevitable to ensure optimal patient outcomes and a safe transition of these patients to adulthood.

Treatment of paroxysmal nocturnal hemoglobinuria in pregnancy with eculizumab: A case report

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease caused by mutations in hematopoietic stem cells leading to pancytopenia and a predisposition for thromboembolic events. In pregnancy, these manifestations can be amplified, leading to increased neonatal and maternal morbidity and mortality. Although data are limited, eculizumab has emerged as a potential treatment of PNH in pregnancy. This report describes a case of a woman with PNH successfully treated with eculizumab during two pregnancies. Although during both pregnancies she experienced breakthrough hemolysis requiring intermittent blood transfusions, she had no thromboembolic events and had term vaginal births. Granted more research is needed, eculizumab may be an acceptable therapy for PNH in pregnancy.

Placental disposition of eculizumab, C5 and C5-eculizumab in two pregnancies of a woman with paroxysmal nocturnal haemoglobinuria

Eculizumab is known to cross the placenta to a limited degree, but recently therapeutic drug levels in cord blood were found in a single case. We report maternal, cord and placental levels of unbound eculizumab, C5 and C5‐eculizumab in two pregnancies of a paroxysmal nocturnal haemoglobinuria patient who received 900 mg eculizumab every 2 weeks. In both pregnancies, cord blood concentrations of unbound eculizumab were below 4 μg/mL, while C5‐eculizumab levels were 22 and 26 μg/mL, suggesting that a considerable fraction of C5 was blocked in the newborn. Concentrations in each placenta of unbound eculizumab were 41 ± 3 and 45 ± 4 μg/g tissue, of C5‐eculizumab 19 ± 2 and 32 ± 3 μg/g, and of C5 20 ± 3 and 30 ± 2 μg/g (mean ± SD, in three tissue samples per placenta). Placental levels of unbound eculizumab were higher than those of C5‐eculizumab complexes, while maternal concentrations were approximately equal, suggesting selective transport of unbound eculizumab across the placenta.

Recent progress in maintenance treatment of neuromyelitis optica spectrum disorder

Background

Treatment of neuromyelitis optica spectrum disorder (NMOSD) has so far been based on retrospective case series. The results of six randomized clinical trials including five different monoclonal antibodies targeting four molecules and three distinct pathophysiological pathways have recently been published.

Methods

Literature search on clinical trials and case studies in NMOSD up to July 10. 2020.

Results

We review mechanism of action, efficacy and side effects, and consequences for reproductive health from traditional immunosuppressants and monoclonal antibodies including rituximab, inebilizumab, eculizumab, tocilizumab and satralizumab.

Conclusion

In NMOSD patients with antibodies against aquaporin 4, monoclonal antibodies that deplete B cells (rituximab and inebilizumab) or interfere with interleukin 6 signaling (tocilizumab and satralizumab) or complement activation (eculizumab) have superior efficacy compared to placebo. Tocilizumab and rituximab were also superior to azathioprine in head-to-head studies. Rituximab, tocilizumab and to some extent eculizumab have well-known safety profiles for other inflammatory diseases, and rituximab and azathioprine may be safe during pregnancy.

Successful Pregnancies During Ongoing Eculizumab Therapy in Two Patients With Complement-Mediated Thrombotic Microangiopathy

In patients with pregnancy-associated complement gene variant-mediated thrombotic microangiopathy (cTMA), terminal complement blockade is used for treatment of cTMA flares during pregnancy or following delivery. We report pregnancy and delivery outcomes of 2 genetically high-risk patients with cTMA, including 1 kidney transplant recipient, during ongoing eculizumab therapy. In both patients, the first manifestation of cTMA occurred independent from pregnancy. One patient has a history of 2 uneventful pregnancies with prophylactic plasma infusions, and the other has a history of early abortion during long-term eculizumab therapy following kidney transplantation. Overall, pregnancy and delivery outcomes under ongoing eculizumab therapy in our 2 patients with preserved kidney function were excellent as compared with other patients reported in the literature. Eculizumab plasma concentrations were maintained in the therapeutic range during pregnancy and were also detectable in cord blood. Results of cord blood analysis showed deficient complement activity, with low factor and regulator levels, most likely reflecting the age of the neonates and presence of eculizumab in cord blood. In conclusion, pregnancy during ongoing eculizumab treatment appeared to be safe in 2 women with a history of high-risk genetic cTMA and excellent kidney function, even following kidney transplantation.