Scientific, ethical, and legal considerations for the inclusion of pregnant people in clinical trials.

Clinical trials to address the COVID-19 public health emergency have broadly excluded pregnant people from participation, illustrating a long-standing trend of clinical trial exclusion that has led to a clear knowledge gap and unmet need in the treatment and prevention of medical conditions experienced during pregnancy and of pregnancy-related conditions. Drugs (includes products such as drugs, biologics, biosimilars and vaccines) approved for a certain medical condition in adults are also approved for use in pregnant adults with the same medical condition, unless contraindicated for use in pregnancy. However, there are limited pregnancy-specific data on risks and benefits of drugs in pregnant people, despite their approval for all adults. The United States Food and Drug Administration-approved medical products are used widely by pregnant people, 90% of whom take at least 1 medication during the course of their pregnancy despite there being sparse data from clinical trials on these products in pregnancy. This overall lack of clinical data precludes informed decision-making, causing clinicians and pregnant patients to have to decide whether to pursue treatment without an adequate understanding of potential effects. Although some United States Food and Drug Administration initiatives and other federal efforts have helped to promote the inclusion of pregnant people in clinical research, broader collaboration and reforms are needed to address challenges related to the design and conduct of trials that enroll pregnant people, and to forge a culture of widespread inclusion of pregnant people in clinical research. This article summarizes the scientific, ethical, and legal considerations governing research conducted during pregnancy, as discussed during a recent subject matter expert convening held by the Duke-Margolis Center for Health Policy and the United States Food and Drug Administration on this topic. This article also recommends strategies for overcoming impediments to inclusion and trial conduct.

Active and inactive influenza virus induction of tumor necrosis factor-alpha and nitric oxide in J774.1 murine macrophages: modulation by interferon-gamma and failure to induce apoptosis.

Infection of J774.1 murine macrophages by influenza A virus (IAV) induces two major responses, production of host defense molecules and death by apoptosis. We investigated whether induction of two cytotoxic compounds, tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO), directly caused IAV-induced apoptosis, and whether induction could be modulated by interferon-gamma (IFN-gamma) or the replication competence of the virus. Live IAV potently induced production of both TNF-alpha and NO, but UV inactivated virus was a poor inducer of both molecules. When cells were pre-treated with IFN-gamma, inactive IAV became as effective an inducer of NO, but not TNF-alpha, as live IAV. Amantadine, which antagonizes viral entry and replication, partly inhibited TNF-alpha and NO production in unprimed cells, but did not inhibit NO in IFN-gamma primed cells. IAV-induced cytotoxicity was not due to the induction of TNF-alpha or NO. Cells were insensitive to either TNF-alpha-containing supernatants or to recombinant TNF-alpha. Anti-TNF-alpha antibody did not protect cells from IAV-induced cell death, and anti-oxidants that inhibited TNF-alpha production also failed to increase cell survival. Inhibitors of NO production did not protect from IAV-induced cell death, either alone or in combination with superoxide dismutase (SOD). We conclude that, even though IAV was a potent inducer of TNF-alpha and NO in macrophages, IAV-induced apoptosis was not mediated directly by them. Importantly, viral replication was not required for the induction of TNF-alpha or NO, and the action of inactive IAV could be potentiated by IFN-gamma.

Characterization of ryanodine receptor-mediated calcium release in human B cells: relevance to diagnostic testing for malignant hyperthermia.

BACKGROUND: Mutations in the ryanodine type 1 receptor (RyR1) are causative for malignant hyperthermia. Studies in human B lymphocytes have shown that measurement of RyR1-mediated intracellular Ca(2+) (Ca(2+)(i)) release can differentiate between normal and malignant hyperthermia-susceptible individuals. The authors have further developed the B-cell assay by pharmacologically characterizing RyR1-mediated Ca release in two normal human B-cell lines and demonstrating increased sensitivity of lymphocytes to the RyR1 agonist 4-chloro-m-cresol (4-CmC) in the porcine model of MH. METHODS: Ca(2+)(i) was measured fluorometrically using fura-2 in populations of cells in suspension or with fluo-4 in single cells using confocal microscopy. The Dakiki and PP normal human B cell lines were used, as well as lymphocytes obtained from normal and malignant hyperthermia-susceptible pigs. 4-CmC was used to elicit RyR1-mediated Ca release; all experiments were performed in the absence of external Ca(2+). RESULTS: EC(50) values for 4-CmC were 0.98 and 1.04 mm for Dakiki and PP cells, respectively, demonstrating reproducibility. The 4-CmC-induced increase in Ca(2+)(i) was eliminated by thapsigargin and was unaffected by xestospongin C. The Ca(2+)(i) increase was separable from mitochondrial stores and was inhibited by azumolene. Caffeine did not induce Ca(2+)(i) release, but ryanodine depleted intracellular stores by 50%. Lymphocytes from pigs carrying the Arg614Cys mutation in RyR1 showed increased sensitivity to 4-CmC (EC(50) = 0.47 vs. 0.81 mm for cells derived from normal animals). CONCLUSIONS: RyR1-mediated Ca(2+) signals can be pharmacologically distinguished from other intracellular sources in human B cells, and alterations of RyR1 function can be successfully detected using Ca(2+) release from intracellular stores as an end point.