Current research on carbetocin and implications for prevention of postpartum haemorrhage

Advancement from Small Peptide Pharmaceuticals to Orally Active Piperazine-2,5-dion-Based Cyclopeptides

The oral delivery of peptide pharmaceuticals has long been a fundamental challenge in drug development. A new chemical platform was designed based on branched piperazine-2,5-diones for creating orally available biologically active peptidomimetics. The platform includes a bio-carrier with "built-in" functionally active peptide fragments or bioactive molecules that are covalently attached via linkers. The developed platform allows for a small peptide to be taken with a particular biological activity and to be transformed into an orally stable compound displaying the same activity. Based on this approach, various peptidomimetics exhibiting hemostimulating, hemosuppressing, and adjuvant activity were prepared. In addition, new examples of a rare phenomenon when enantiomeric molecules demonstrate reciprocal biological activity are presented. Finally, the review summarizes the evolutionary approach of the short peptide pharmaceutical development from the immunocompetent organ separation to orally active cyclopeptides and peptidomimetics.

Case report: A relatively rare adverse event caused by carbetocin- placenta interception

Placenta interception is extremely rare, and herein, we report the case of a 33-year-old woman with placenta interception during cesarean section caused by carbetocin, which was intravenously injected immediately after delivery of the infant to prevent postpartum hemorrhage. There was no sign of placental separation in the third stage of labor. A protuberance with gross subserous blood vessels in the left fundus of the uterus was detected and was misdiagnosed as placental accreta. The patient was transferred to the district referral hospital to manage the protuberance after stitching up the incision. On opening the original incision in the tertiary hospital, the protuberance disappeared, and the placenta was found in the lower segment of the uterus cavity. The intercepted placenta showed a spontaneous resolution from the uterine wall and was removed intact. This case report details the typical presentation of placenta interception to make obstetricians aware of the possibility that carbetocin might lead to this adverse event.

Epidemiology and definition of PPH worldwide

Postpartum/peripartum hemorrhage (PPH) is an obstetric emergency complicating 1-10% of all deliveries and is a leading cause of maternal mortality and morbidity worldwide. However, the incidence of PPH differs widely according to the definition and criteria used, the way of measuring postpartum blood loss, and the population being studied with the highest numbers in developing countries. Despite all the significant progress in healthcare, the incidence of PPH is rising due to an incomplete implementation of guidelines, resulting in treatment delays and suboptimal care. A consensus clinical definition of PPH is needed to enable awareness, early recognition, and initiation of appropriate intensive treatment. Unfortunately, the most used definition of PPH based on blood loss ≥500 ml after delivery suffers from inaccuracies in blood loss quantification and is not clinically relevant in most cases, as the amount of blood loss does not fully reflect the severity of bleeding.

Effectiveness and safety of carboxytocin versus oxytocin in preventing postpartum hemorrhage: A systematic review and meta-analysis

OBJECTIVE

This study compared the effectiveness and safety of carbetocin and oxytocin in preventing postpartum hemorrhage (PPH).

METHODS

A systematic literature search was performed on PubMed, Embase, and the Cochrane Library for relevant studies published up to February 2019. Next, two independent reviewers screened the studies according to the selection criteria as well as the strategies recommended by the Cochrane Collaboration. Data were then extracted and evaluated. All statistical analyses were performed using RevMan 5.1.

RESULTS

A total of 24 studies involving 37 383 patients were included for analysis. For cesarean section patients, carbetocin was superior to oxytocin in reduction of the need for additional uterine contraction (odds ratio [OR] = 0.48, 95% confidence interval [CI] [0.35, 0.65], p < 0.00001), PPH (OR = 0.70, 95% CI [0.51, 0.95], p = 0.02), blood loss (mean [MD] = -64.36, 95% CI [-107.78, -20.93], p = 0.004), and transfusion (OR = 0.59, 95% CI [0.42, 0.82], p = 0.002), and there was no significant difference in severe PPH (OR = 0.84, 95% CI [0.66, 1.090], p = 0.19). For vaginal delivery patients, carbetocin was superior to oxytocin in reduction of the need for additional uterine contractions (OR = 0.48, 95% CI [0.25, 0.93], p = 0.03), PPH (OR = 0.28, 95% CI [0.09, 0.91], p = 0.03), and blood loss (MD = -63.52, 95% CI [-113.43, -13.60], p = 0.01), and there were no significant differences in severe PPH (OR = 0.82, 95% CI [0.40, 1.69], p = 0.59) and transfusion (OR = 0.60, 95% CI [0.22, 1.61], p = 0.31). With regard to safety, for cesarean section patients, carbetocin was superior to oxytocin in reduction of the incidence of headache (OR = 0.72, [0.55, 0.95], p = 0.02), and there were no significant differences in nausea, vomiting, abdominal pain, flushing, tremors, itching, dizziness, and fever. For vaginal delivery patients, there were no significant differences in nausea, vomiting, headache, abdominal pain, flushing, tremors, itching, dizziness, and fever between the two drugs.

CONCLUSION

For patients undergoing cesarean section and vaginal delivery, carbetocin was superior to oxytocin in effectiveness and similar in safety. Therefore, carbetocin is expected to be an alternative uterine contraction agent for preventing PPH.

Therapeutic peptides: current applications and future directions

Peptide drug development has made great progress in the last decade thanks to new production, modification, and analytic technologies. Peptides have been produced and modified using both chemical and biological methods, together with novel design and delivery strategies, which have helped to overcome the inherent drawbacks of peptides and have allowed the continued advancement of this field. A wide variety of natural and modified peptides have been obtained and studied, covering multiple therapeutic areas. This review summarizes the efforts and achievements in peptide drug discovery, production, and modification, and their current applications. We also discuss the value and challenges associated with future developments in therapeutic peptides.

Effects of tranexamic acid on the amount of bleeding following vaginal delivery and its adverse effects: a double-blind placebo controlled randomized clinical trial

INTRODUCTION

Postpartum hemorrhage (PPH) is the most important concern after delivery. Tranexamic acid (TXA), an anti-fibrinolytic agent, has been suggested for prevention and treatment of PPH.

OBJECTIVE

The purpose of the present study was to find the effects of TXA on the amount of bleeding following vaginal delivery and its adverse effects.

MATERIALS AND METHODS

The study was performed as a randomized double blind placebo controlled clinical trial on low risk pregnant women who delivered vaginally. The patients were randomly assigned into two groups. Women in the intervention group received 10 mg/kg infusion of TXA in 100 mL normal saline and the control group received one vial of distilled water (as placebo) in 100 mL normal saline. The primary outcome was amount of bleeding after delivery. The secondary outcomes were decreased in hemoglobin level, need for additional uterotonic agents and need for blood transfusion. All were evaluated 6 h after delivery and compared in the two groups. Participants were followed up to six weeks after delivery for any TXA side effects.

RESULTS

Two hundred and seven women finished the study. There were no significant differences between the two groups in terms of demographic data and risk factors for bleeding. Mean blood loss and need to misoprostol was more in the control group (p=.033 and p=.000, respectively). Hemoglobin level was higher in the TXA group 6 h after delivery. None of the subjects needed blood transfusion, uterine balloon tamponade or emergency hysterectomy. Adverse effects were higher in the TXA group, however, there were no side effects between weeks 3 and 6 in both groups. There were no thromboembolic events during six weeks after delivery.

CONCLUSIONS

Tranexamic acid can reduce the amount of bleeding after vaginal delivery in low risk women without having serious complications. Also, it may decrease the need for additional uterotonic agents. Trial registration number and registry website: IRCT20091023002624N22.

Why are women still dying from obstetric hemorrhage? A narrative review of perspectives from high and low resource settings

The possibility of hemorrhage will always co-exist with pregnancy, whether anticipated or not. It remains the unwelcome guest in the corner of every delivery room, stealing the lives of young women every day across the globe. In 2014, the World Health Organization reported that hemorrhage was the leading contributor to maternal mortality worldwide, with nearly 75% of maternal deaths due to postpartum hemorrhage. In low resource settings, while maternal mortality is decreasing, hemorrhage remains the single most important contributor to maternal death. Hospital-based deliveries with skilled birth attendants have been encouraged to improve outcomes and, as a result, hospital births have dramatically increased. However, access to higher levels of emergency obstetric care as well as blood products and therapeutic resources remain limiting factors. Meanwhile, in high resource settings, maternal mortality from hemorrhage is increasing, particularly among women of color. While very rare, mortality from hemorrhage generally follows medical interventions such as surgical management of placenta accreta or emergency cesarean section. Primary prevention therefore requires careful selection and conduct of medical interventions, as well as the provision of high quality, supportive, and safe maternity care. It is clear that there is not one single solution in preventing obstetric hemorrhage on a global scale. The international community must employ creative solutions to reduce this ever-present problem.

Access to oxytocin and misoprostol for management of postpartum haemorrhage in Kenya, Uganda and Zambia: a cross-sectional assessment of availability, prices and affordability

OBJECTIVE

To assess access (availability and affordability) to oxytocin and misoprostol at health facilities in Kenya, Uganda and Zambia to improve prevention and management of postpartum haemorrhage (PPH).

DESIGN

The assessment was undertaken using data from Health Action International (HAI) research on sexual and reproductive health commodities based on a cross-sectional design adapted from the standardised WHO/HAI methodology.

SETTING

Data were collected from 376 health facilities in in Kenya, Uganda and Zambia in July and August 2017.

OUTCOME MEASURES

Availability was calculated as mean percentage of sampled medicine outlets where medicine was found on the day of data collection. Medicine prices were compared with international reference prices (IRP) and expressed as median price ratios. Affordability was calculated using number of days required to pay for a standard treatment based on the daily income of the lowest paid government worker.

RESULTS

Availability of either oxytocin or misoprostol at health facilities was high; 81% in Kenya, 82% in Uganda and 76% in Zambia. Oxytocin was more available than misoprostol, and it was most available in the public sector in the three countries. Availability of misoprostol was highest in the public sector in Uganda (88%). Oxytocin and misoprostol were purchased by patients at prices above IRP, but both medicines cost less than a day's wages and were therefore affordable. Availability of misoprostol was poor in rural settings where it would be more preferred due to lack of trained personnel and cold storage facilities required for oxytocin.

CONCLUSION

Availability and affordability of either oxytocin or misoprostol at health facilities met the WHO benchmark of 80%. However, countries with limited resources should explore mechanisms to optimise management of PPH by improving access to misoprostol especially in rural areas.

Comparison of the pharmacologic profiles of arginine vasopressin and oxytocin analogs at marmoset, titi monkey, macaque, and human oxytocin receptors

The oxytocin-arginine vasopressin (OT-AVP) ligand-receptor family influences a variety of physiological, behavioral, and social behavioral processes in the brain and periphery. The OT-AVP family is highly conserved in mammals, but recent discoveries have revealed remarkable diversity in OT ligands and receptors in New World Monkeys (NWMs) providing a unique opportunity to assess the effects of genetic variation on pharmacological signatures of peptide ligands. The consensus mammalian OT sequence has leucine in the 8^th position (Leu⁸-OT), whereas a number of NWMs, including the marmoset, have proline in the 8^th position (Pro⁸-OT) resulting in a more rigid tail structure. OT and AVP bind to OT’s cognate G-protein coupled receptor (OTR), which couples to various G-proteins (G_i/o, G_q, G_s) to stimulate diverse signaling pathways. CHO cells expressing marmoset (mOTR), titi monkey (tOTR), macaque (qOTR), or human (hOTR) OT receptors were used to compare AVP and OT analog-induced signaling. Assessment of G_q-mediated increase in intracellular calcium (Ca²⁺) demonstrated that AVP was less potent than OT analogs at OTRs from species whose endogenous ligand is Leu⁸-OT (tOTR, qOTR, hOTR), relative to Pro⁸-OT. Likewise, AVP-induced membrane hyperpolarization was less potent at these same OTRs. Evaluation of (Ca²⁺)-activated potassium (K⁺) channels using the inhibitors apamin, paxilline, and TRAM-34 demonstrated that both intermediate and large conductance Ca²⁺-activated K⁺ channels contributed to membrane hyperpolarization, with different pharmacological profiles identified for distinct ligand-receptor combinations. Understanding more fully the contributions of structure activity relationships for these peptide ligands at vasopressin and OT receptors will help guide the development of OT-mediated therapeutics.

Current Resources for Evidence-Based Practice, March 2019

A review of new resources to support the provision of evidence-based care for women and infants.

Translating research evidence into practice: a report from the 2nd International Conference on Maternal and Newborn Health from KLE University - Belagavi, India

The Jawaharlal Nehru Medical College (JNMC) Women's and Children's Health Research Unit (WCHRU) of the Karnataka Lingayat Education (KLE) Academy of Higher Education and Research Deemed-to-be-University and its collaborators convened the '2nd International Conference on Maternal and Newborn Health -Translating Research Evidence to Practice' to address the common theme of improving maternal and newborn health in low- and middle- income countries (LMIC). This supplement, including 16 manuscripts, reflects much of the research presented at the conference, including analyses of the state of knowledge, as well as completed, ongoing and planned research in these areas conducted by the WCHRU in India together with many collaborators across high-income and LMIC. The first paper reviews maternal, fetal and neonatal mortality in low-income countries, considers their causes, as well as evidence for potential interventions to reduce mortality. A second paper addresses near miss maternal mortality. Several manuscripts address the research conducted by WCHRU and their colleagues in a multi-center research network. One study examines rates of miscarriage and medically terminated pregnancy in India and the risk factors for these occurrences. Another paper addresses stillbirth and its risk factors, both in India as well as in other LMIC. Haemorrhage and preeclampsia/eclampsia, important causes of maternal mortality, stillbirth and neonatal morbidity in LMIC, are addressed in a series of papers summarizing trials of interventions to reduce improve outcomes associated with these conditions. Poor maternal and infant nutritional status, which contribute to adverse outcomes, are addressed through papers which describe a number of important studies that the WCHRU and their colleagues have conducted to attempt to improve nutritional status. Another paper describes a study to investigate causes of stillbirth and deaths among preterm births, which will utilize new techniques to investigate the infectious causes of these deaths. Finally, the supplement addresses the process for dissemination of research results to inform public policy. Together these manuscripts represent a body of research to inform interventions to reduce maternal, fetal and newborn mortality and illustrates what a dedicated research group together with institutional support can accomplish.