Absence of developmental toxicity in a canine model after infusion of a hemoglobin-based oxygen carrier: Implications for risk assessment

Use of cell salvage and HBOC-201 in a pregnant Jehovah's Witness with sickle beta+thalassaemia undergoing emergency caesarean section

Patients with severe anaemia who refuse or cannot safely receive red cell transfusion present challenges during pregnancy, delivery and the postpartum period. Strategies including HBOC-201 (Hemopure) and intraoperative use of cell salvage have been used in non-pregnant patients to improve oxygen carrying capacity; however, these products pose unique risks in pregnant patients, those with sickle cell disease (SCD) and those undergoing caesarean section (C-section). We describe a case of a pregnant sickle beta+thalasasaemia patient who presented at 27 weeks gestation with pre-eclampsia and severe anaemia. As a Jehovah's Witness, she declined allogenic blood transfusion. The patient successfully underwent emergent C-section with cell salvage and received HBOC-201 immediately after delivery, during the operative procedure. To our knowledge, this is the first published report documenting a Jehovah's Witness patient with SCD who successfully received cell salvage and then HBOC-201 immediately postdelivery.

Scientific and Regulatory Policy Committee Points to Consider Review: Inclusion of Reproductive and Pathology End Points for Assessment of Reproductive and Developmental Toxicity in Pharmaceutical Drug Development

Standard components of nonclinical toxicity testing for novel pharmaceuticals include clinical and anatomic pathology, as well as separate evaluation of effects on reproduction and development to inform clinical development and labeling. General study designs in regulatory guidances do not specifically mandate use of pathology or reproductive end points across all study types; thus, inclusion and use of these end points are variable. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology (STP) formed a Working Group to assess the current guidelines and practices on the use of reproductive, anatomic pathology, and clinical pathology end points in general, reproductive, and developmental toxicology studies. The Working Group constructed a survey sent to pathologists and reproductive toxicologists, and responses from participating organizations were collected through the STP for evaluation by the Working Group. The regulatory context, relevant survey results, and collective experience of the Working Group are discussed and provide the basis of each assessment by study type. Overall, the current practice of including specific end points on a case-by-case basis is considered appropriate. Points to consider are summarized for inclusion of reproductive end points in general toxicity studies and for the informed use of pathology end points in reproductive and developmental toxicity studies.

Developmental toxicity in rats of a hemoglobin-based oxygen carrier results from impeded function of the inverted visceral yolk sac

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Infusion HBOC into pregnant rats causes developmental toxicity.

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Sensitive from GD 7 to 11 when inverted yolk sac placenta (invYSP) supplies nutrition.

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Controls for protein content, oncotic properties and Hb show effects are due to Hb.

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Whole embryo culture verified HBOC interference with invYSP function.

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Humans lack invYSP and are unlikely to be affected by HBOC.

HBOC-201 is a bovine-derived, cross-linked, and stabilized hemoglobin (250 kDa) in physiological saline. Daily intravenous infusions of HBOC (1.95, 3.90, or 5.85 g/kg/day) during gestational days (GDs) 6–18 in Sprague-Dawley rats caused fetal mortality, reduced birth weight, and malformations. Subsequent single-day infusions (5.85 g/kg/day) showed that developmental toxicity was limited to GDs 7–9 when histiotrophic nutrition via the inverted visceral yolk sac (invVYS) is essential. Histiotrophic nutrition is receptor-mediated endocytosis of bulk maternal proteins and subsequent lysosomal degradation providing amino acids and other nutrients for embryonic growth. Controls for protein content, oncotic properties, and hemoglobin content indicated that toxicity was due to hemoglobin. Rat whole embryo cultures verified HBOC interference with invVYS transport capacity and resultant deficient embryonic nutrition. These mechanisms of action are not expected to impact human development based on differences in VYS morphology and function, although a complete understanding of early human embryonic nutrition is lacking.