Sporozoite immunization: innovative translational science to support the fight against malaria.

INTRODUCTION: Malaria, a devastating febrile illness caused by protozoan parasites, sickened 247,000,000 people in 2021 and killed 619,000, mostly children and pregnant women in sub-Saharan Africa. A highly effective vaccine is urgently needed, especially for Plasmodium falciparum (Pf), the deadliest human malaria parasite. AREAS COVERED: Sporozoites (SPZ), the parasite stage transmitted by Anopheles mosquitoes to humans, are the only vaccine immunogen achieving >90% efficacy against Pf infection. This review describes >30 clinical trials of PfSPZ vaccines in the U.S.A., Europe, Africa, and Asia, based on first-hand knowledge of the trials and PubMed searches of 'sporozoites,' 'malaria,' and 'vaccines.' EXPERT OPINION: First generation (radiation-attenuated) PfSPZ vaccines are safe, well tolerated, 80-100% efficacious against homologous controlled human malaria infection (CHMI) and provide 18-19 months protection without boosting in Africa. Second generation chemo-attenuated PfSPZ are more potent, 100% efficacious against stringent heterologous (variant strain) CHMI, but require a co-administered drug, raising safety concerns. Third generation, late liver stage-arresting, replication competent (LARC), genetically-attenuated PfSPZ are expected to be both safe and highly efficacious. Overall, PfSPZ vaccines meet safety, tolerability, and efficacy requirements for protecting pregnant women and travelers exposed to Pf in Africa, with licensure for these populations possible within 5 years. Protecting children and mass vaccination programs to block transmission and eliminate malaria are long-term objectives.

Primary treatment regimen and diabetes insipidus as predictors of health outcomes in adults with childhood-onset craniopharyngioma.

CONTEXT: Craniopharyngiomas are often associated with significant morbidity due to their location and treatment effects. Little is known of the effects of primary treatment regimen and diabetes insipidus (DI), a clinical surrogate of hypothalamic obesity, on health outcomes in adults with childhood-onset craniopharyngioma (COCP). OBJECTIVE: The objective of the study was to examine health outcomes of adults with COCP based on primary treatment regimens and the presence of DI. DESIGN: This study included a retrospective KIMS (Pfizer International Metabolic Database) data analysis of 180 adults with COCP according to the primary treatment regimen [one surgery (1Surg) vs complex treatment regimen (CTrR) of more than 1Surg and/or radiotherapy] and the presence of DI. RESULTS: The majority of COCP patients underwent transcranial surgery (77%) without receiving radiotherapy (84%). Compared with the 1Surg group, more CTrR patients developed visual field defects and ophthalmoplegia (all P < .01). Compared with patients without DI, those with DI had higher rates of anterior pituitary hormone deficits, body mass index, and fat mass (all P < .01). By contrast, fasting glucose, hemoglobin A1c, lipid panel, and quality of life were comparable among 1Surg vs CTrR patients, and patients with vs without DI. Regardless of primary treatment received, the presence of DI in either group was associated with higher rates of anterior pituitary hormone deficits and obesity. CONCLUSION: CTrR and DI predicted health outcomes differently. CTrR predisposed to the development of visual dysfunction, whereas DI was associated with higher rates of anterior pituitary dysfunction and weight gain. Higher body mass index and fat mass in patients with DI further implicate the role of hypothalamic damage as an important causal factor of obesity in these patients.

Clinical characteristics and effects of GH replacement therapy in adults with childhood-onset craniopharyngioma compared with those in adults with other causes of childhood-onset hypothalamic-pituitary dysfunction.

OBJECTIVE: Adults with childhood-onset (CO) craniopharyngioma (COCP) have poor quality of life (QoL) and clinical outcomes, but few studies have compared these patients with adults with other causes of CO hypothalamic-pituitary dysfunction. In this study, we compared baseline clinical characteristics and patient-reported outcomes before starting GH replacement therapy in adults with GH deficiency (GHD) due to COCP with those of adults either with CO idiopathic/congenital hypopituitarism (COH) or with CO extrasellar (COE) tumours, and evaluated the 1- and 5-year effects of GH replacement therapy. SUBJECTS AND METHODS: Retrospective analysis of the data recorded in KIMS (Pfizer International Metabolic Database) was carried out. Patients with COCP, COH and COE tumours were evaluated at baseline, and after 1 and 5 years of therapy. RESULTS: Compared with COH and COE patients, more COCP patients underwent surgery, had greater abnormalities of body composition and higher prevalence of pituitary hormone deficits (all P<0.001), but comparable fasting glucose, HbA1c, total cholesterol and LDL-cholesterol levels, marital status, parenthood, living arrangements, education, employment and annual sick-leave days. After 1 and 5 years of GH replacement therapy, similar changes were evident with regard to body composition, fasting glucose and HbA1c levels, QoL, and the level of and satisfaction with physical activity across the three groups. CONCLUSIONS: Adults with untreated COCP with GHD at baseline demonstrated more co-morbidities including greater abnormalities of body composition, pituitary hormone deficits and visual field defects. Overall, adults with COCP, COH and COE tumours responded comparably to short- and long-term GH replacement therapy, suggesting that patients with GHD due to COCP benefited from GH replacement therapy to a similar degree as those with other causes of CO hypothalamic-pituitary dysfunction did.

A review of guidelines for use of growth hormone in pediatric and transition patients.

Growth hormone (GH) is approved by the US Food and Drug Administration (FDA) for use in pediatric patients with disorders of growth failure or short stature and in adults with growth hormone deficiency (GHD) and HIV/AIDS wasting and cachexia. For pediatric patients, guidelines for the use of GH have been developed by several organizations that have identified specific criteria for initiating GH therapy for each FDA-approved indication. Guidelines for adults have also been developed and include recommendations for transition (adolescent) patients with GHD. These patients are often treated with GH as children but may require continued treatment as young adults to attain full skeletal mineralization and improve cardiovascular risk factors. Adult and pediatric guidelines are supported by efficacy and safety studies, which show that, when started at an early age, GH treatment can increase growth velocity and that GH is safe and well-tolerated. We summarize the guidelines that are available for all FDA-approved indications among pediatric and transition patients. Adherence to these guidelines will help to ensure that patients with disorders of growth failure or short stature receive the necessary therapy to increase linear growth and transition smoothly to healthy adulthood.

Unreplaced sex steroid deficiency, corticotropin deficiency, and lower IGF-I are associated with lower bone mineral density in adults with growth hormone deficiency: a KIMS database analysis.

CONTEXT: GH deficiency (GHD) is associated with low bone mineral density (BMD). Risk factors for lower BMD in this GHD population have not been fully elucidated. In particular, there are limited published data in GH-naïve subjects. OBJECTIVE: The objective of the study was to identify endocrine correlates of low BMD in treatment-naïve adult GHD subjects. DESIGN: This was a retrospective analysis of data extracted from the (Pfizer International Metabolic Study) KIMS database. SETTING: The study was an international epidemiological survey of more than 15,000 adult GHD patients from 31 countries. PATIENTS: A total of 1218 subjects with stringently defined GHD of adult onset (641 women and 577 men) who were GH naïve and had BMD measured in the posterior anterior lumbar spine and femoral neck by dual-energy X-ray absorptiometry. MAIN OUTCOME MEASURES: Variables associated with standardized BMD (sBMD) in adult-onset GHD were examined. RESULTS: In the LS, body mass index (r = 0.13, P < 0.01), unreplaced sex steroid deficiency (r = -0.17, P < 0.0001), and corticotropin deficiency (r = -0.11, P < 0.01) were independently associated with sBMD. In the FN, age (r = -0.19, P < 0.0001), female gender (r = -0.18, P < 0.0001), body mass index (r = 0.21, P < 0.0001), and decreased IGF-I SD scores (r = 0.10, P < 0.001) were independently associated with sBMD. CONCLUSIONS: Hormone variables associated with lower sBMD in patients with adult-onset GHD include unreplaced sex steroid deficiency and corticotropin deficiency in the LS and lower IGF-I SDS in the FN.

Acromegaly: a review of current medical therapy and new drugs on the horizon.

Acromegaly is a disease that results from a growth hormone (GH)­secreting pituitary tumor. Clinically, the disease is characterized by excessive skeletal growth, soft tissue enlargement with disfigurement, and increased risk of cardiovascular death. The goals of treatment are the removal or reduction of the tumor mass via surgery and normalization of GH secretion. Another treatment goal is the preservation of normal pituitary function if possible. Transsphenoidal surgery by an experienced neurosurgeon is usually the first line of therapy, especially for small tumors. Surgeon expertise is crucial for outcome, with dedicated pituitary surgeons having better results. However, overall cure rates remain low because patients with these tumors usually present at an incurable stage. Therefore, medical therapy to control excess GH secretion plays a significant role in a large proportion of patients with acromegaly who are not cured by surgery or other forms of therapy, such as radiotherapy, and/or are awaiting the effects of radiotherapy. If surgery is not curative, lifelong monitoring and the control of excess GH is usually necessary by a care team experienced in handling this chronic disease. In the past decade major progress has occurred in the development of highly specific and selective pharmacological agents that have greatly facilitated more aggressive management of active acromegaly. Treatment approach should be individualized and take into consideration a patient's tumor size and location, symptoms, comorbid conditions, and preferences. Because a surgical cure can be difficult to achieve, all patients, even those with what seems to be a clinically and biochemically inactive disease, should undergo long-term biochemical testing and pituitary MR imaging.

Evaluation of the pituitary function with insulin tolerance (hypoglycaemia) testing: are there any differences using insulin lispro compared to regular insulin?

BACKGROUND/AIM: The insulin tolerance test (ITT) remains the gold standard for evaluating the pituitary function, but has potential risks when hypoglycaemia is induced. There are scarce data using short-acting insulin analogs for ITTs. This pilot study compares the effects of insulin lispro (LPI) with regular insulin (RGI) during an ITT. METHODS: Patients with suspected hypopituitarism (n = 103) randomly received either LPI (n = 51) or RGI (n = 52). RESULTS: All patients reported signs and symptoms when hypoglycaemia was induced. In the LPI group, hypoglycaemia occurred sooner (23.6 +/- 1.6 vs. 28.3 +/- 1.4 min, p < 0.05), and duration of hypoglycaemia (25.0 +/- 1.7 vs. 31.9 +/- 1.9 min, p < 0.05) and time for blood glucose levels to return to a 'safe' level (>3.3 mmol/l; 56.5 +/- 2.3 vs. 76.0 +/- 2.1 min, p < 0.001) were shorter as compared with the RGI group. No differences in peak growth hormone and cortisol levels were observed between the two groups. CONCLUSIONS: Our data suggest that despite inducing similar symptomatology, LPI exerted a quicker onset and a shorter duration of hypoglycaemia as compared with RGI. Thus, using LPI might reduce the potential risks associated with an ITT by shortening the hypoglycaemic phase of the test.

Prevalence of GH and other anterior pituitary hormone deficiencies in adults with nonsecreting pituitary microadenomas and normal serum IGF-1 levels.

OBJECTIVE: GH is usually the first pituitary hormone to be affected following a pathological insult to the pituitary; however, data on the prevalence of GH deficiency in patients with nonsecreting pituitary microadenomas and normal serum IGF-1 levels are scarce. This study aims to evaluate the prevalence of GH and other anterior pituitary hormone deficiencies, and to determine whether microadenomas per se could be associated with reduced GH response rates to GHRH-arginine stimulation. DESIGN: Analytical, retrospective, two-site case-control study. PATIENTS AND METHODS: Thirty-eight patients with nonsecreting pituitary microadenomas (mean size 4.2 mm) and normal serum IGF-1 levels were studied. Anterior pituitary function testing, including the GHRH-arginine test to examine GH reserve, was performed in all patients. Serum IGF-1 levels and peak GH levels in the patients that passed the GHRH-arginine test were compared with 22 age- and BMI-matched healthy controls. RESULTS: Nineteen patients (50%) failed the GHRH-arginine test and had higher body mass index (BMI) than those that passed the GHRH-arginine test and healthy controls. Peak GH levels in patients that passed the GHRH-arginine test were lower compared to healthy controls and 19 patients (50%) had at least one other pituitary hormone deficit. A negative correlation (r = -0.42, P < 0.01) between peak GH levels and BMI was identified, but no correlations were found between peak GH and serum IGF-1 levels. CONCLUSIONS: Our data demonstrated that a substantial number of patients with nonsecreting pituitary microadenomas failed the GHRH-arginine test despite normal serum IGF-1 levels, and had at least one other pituitary hormone deficiency, suggesting that nonsecreting microadenomas may not be clinically harmless. We therefore recommend long-term follow-up with periodic basal pituitary function testing, and to consider dynamic pituitary testing should clinical symptoms arise in these patients.

Effect of growth hormone replacement on BMD in adult-onset growth hormone deficiency.

UNLABELLED: To determine if replacement of GH improves BMD in adult-onset GHD, we administered GH in physiologic amounts to men and women with GHD. GH replacement significantly increased spine BMD in the men by 3.8%. INTRODUCTION: Growth hormone (GH) deficiency (GHD) acquired in adulthood results in diminished BMD; the evidence that replacement of GH improves BMD is not conclusive. We therefore performed a randomized, placebo-controlled trial to determine whether GH replacement would increase lumbar spine BMD in a combined group of men and women with adult-onset GHD. MATERIALS AND METHODS: We randomized 67 men and women to receive GH (n=33) or placebo (n=34) for 2 yr. The GH dose was initially 2 microg/kg body weight/d, increased gradually to a maximum of 12 microg/kg/d and adjusted to maintain a normal IGF-I concentration for age and sex. BMD was assessed before treatment and at 6, 12, 18, and 24 mo of treatment. Fifty-four subjects completed the protocol. RESULTS: BMD of the lumbar spine in the entire group increased by 2.9 +/- 3.9% above baseline in the GH-treated subjects, which was significantly (p=0.037) greater than the 1.4 +/- 4.5% increase in the placebo-treated subjects. In a secondary analysis, spine BMD in GH-treated men increased 3.8 +/- 4.3% above baseline, which was significantly (p=0.001) greater than that in placebo-treated men (0.4 +/- 4.7%), but the change in GH-treated women was not significantly different from that in placebo-treated women. Treatment with GH did not increase total hip BMD more than placebo treatment after 2 yr. CONCLUSIONS: We conclude that GH replacement in men who have adult-onset GHD improves their spine BMD, but we cannot draw any conclusions about the effect of GH replacement on spine BMD in women with adult-onset GHD.

Is further evaluation for growth hormone (GH) deficiency necessary in fibromyalgia patients with low serum insulin-like growth factor (IGF)-I levels?

OBJECTIVE: Fibromyalgia (FM) is characterized by diffuse pain, fatigue, and sleep disturbances; symptoms that resemble the adult growth hormone (GH) deficiency syndrome. Many FM patients have low serum GH levels, with a hypothesized aetiology of dysregulated GH/insulin-like growth factor (IGF)-I axis. The aim of this study was to assess the GH reserve in FM patients with low serum IGF-I levels using the GH-releasing hormone (GHRH)-arginine test. DESIGN: We retrospectively reviewed the GHRH-arginine data of 77 FM patients with low serum IGF-I levels referred to our tertiary unit over a 4-year period. RESULTS: Of the 77 FM patients, 13 patients (17%) failed the GHRH-arginine test. Further evaluation with pituitary imaging revealed normal pituitary glands (n=7), coincident microadenomas (n=4), empty sella (n=1) and pituitary cyst (n=1), and relevant medical histories such as previous head injury (n=4), Sheehan's syndrome (n=1), and whiplash injury (n=1). In contrast, the remaining 64 patients (83%) that responded to the GHRH-arginine test demonstrated higher peak GH levels compared to age and BMI-matched controls (n=24). CONCLUSION: Our data shows that a subpopulation of FM patients with low serum IGF-I levels will fail the GHRH-arginine test. We, thus, recommend that the GH reserve of these patients should be evaluated further, as GH replacement may potentially improve the symptomatology of those with true GH deficiency. Additionally, the increased GH response rates to GHRH-arginine stimulation in the majority of FM patients with low serum IGF-I levels further supports the hypothesis of a dysregulated GH/IGF-I axis in the pathophysiology of FM.

Growth hormone and estrogen: a clinician's approach.

Adult patients with growth hormone (GH) deficiency require long-term treatment with GH to support normal physiological functioning. For many female patients, endogenous estrogen levels have a considerable impact on the dosing requirements for GH. Estrogen appears to stimulate GH secretion by decreasing liver secretion of insulin-like growth factor-I (IGF-I), resulting in stimulation of the pituitary to synthesize and secrete GH. Oral estrogen results in a higher concentration of liver estrogen than transdermal administration of estrogen. The appropriate dose of GH needs to be determined for each patient based on his or her age, sex, concomitant estrogen therapy, IGF-I level, and short- and long-term response to therapy. Clinical endocrinologists are in the best position to put all these variables into a successful therapeutic scenario.

Shouldn't adults with growth hormone deficiency be offered growth hormone replacement therapy?

Growth hormone as therapy for adults with growth hormone deficiency has not been universally accepted by endocrinologists who treat adult patients. The following are addressed in this commentary: the evidence on safety and efficacy in the literature supporting the idea that growth hormone should be offered as replacement therapy to adults who are growth hormone deficient; common concerns of the average prescribing endocrinologist, including the purported association between insulin-like growth factor-I and malignant neoplasms and quality-of-life issues with long-term therapy; and controversial subjects, such as differences in dosing for adults versus children and diagnostic issues. This analysis should encourage reluctant practitioners to at least consider growth hormone replacement therapy for patients with definite growth hormone deficiency--that is, patients with symptomatic panhypopituitarism.