Economic burden of patients with post-surgical chronic and transient hypoparathyroidism in the United States examined using insurance claims data

BACKGROUND

Hypoparathyroidism (HP) is a rare endocrine disease commonly caused by the removal or damage of parathyroid glands during surgery and resulting in transient (tHP) or chronic (cHP) disease. cHP is associated with multiple complications and comorbid conditions; however, the economic burden has not been well characterized. The objective of this study was to evaluate the healthcare resource utilization (HCRU) and costs associated with post-surgical cHP, using tHP as a reference.

METHODS

This analysis of a US claims database included patients with both an insurance claim for HP and thyroid/neck surgery between October 2014 and December 2019. cHP was defined as an HP claim ≥ 6 months following surgery and tHP was defined as only one HP claim < 6 months following surgery. The cHP index date was the first HP diagnosis claim following their qualifying surgery claim, whereas the tHP index date was the last HP diagnosis claim following the qualifying surgery claim. Patients were continuously enrolled at least 1 year pre- and post-index. Patients' demographic and clinical characteristics, all-cause HCRU, and costs were descriptively analyzed. Total all-cause costs were calculated as the sum of payments for hospitalizations, emergency department, office/clinic visits, and pharmacy.

RESULTS

A total of 1,406 cHP and 773 tHP patients met inclusion criteria. The average age (52.1 years cHP, 53.5 years tHP) and representation of females (83.2% cHP, 81.2% tHP) were similar for both groups. Neck dissection surgery was more prevalent in cHP patients (23.6%) than tHP patients (5.3%). During the 1-2 year follow-up period, cHP patients had a higher prevalence of inpatient admissions (17.4%), and emergency visits (26.0%) than the reference group -tHP patients (14.4% and 21.4% respectively). Among those with a hospitalization, the average number of hospitalizations was 1.5-fold higher for cHP patients. cHP patients also saw more specialists, including endocrinologists (28.7% cHP, 15.8% tHP), cardiologists (16.7% cHP, 9.7% tHP), and nephrologists (4.6% cHP, 3.3% tHP).

CONCLUSION

This study demonstrates the increased healthcare burden of cHP on the healthcare system in contrast to patients with tHP. Effective treatment options are needed to minimize the additional resources utilized by patients whose HP becomes chronic.

An Open-Label Phase 2 Study of Eneboparatide, a Novel PTH Receptor 1 Agonist, in Hypoparathyroidism

CONTEXT

Hypoparathyroidism is a rare disorder characterized by a deficiency in parathyroid hormone (PTH) resulting in hypocalcemia, hyperphosphatemia, and hypercalciuria. Eneboparatide is an investigational peptide agonist of the PTH1 receptor for the treatment of chronic hypoparathyroidism (HP).

OBJECTIVE

To evaluate the efficacy, safety, and tolerability of eneboparatide in HP patients.

DESIGN

Open-label, phase 2 study.

PARTICIPANTS

Twenty-eight patients (21 women, 7 men), mean age (range): 58 years (28-72), with HP were enrolled into 2 consecutive cohorts (C1, n = 12, and C2, n = 16).

INTERVENTION

Following an optimization period, daily subcutaneous injections of eneboparatide were administered for 3 months at 20 µg/day (C1) or 10 µg/day (C2) starting dose. Conventional therapy was progressively removed and eneboparatide could be titrated up to 60 µg (C1) or 80 µg (C2).

MAIN OUTCOMES

Proportion of patients achieving independence from conventional therapy, albumin-adjusted serum calcium (ADsCa), 24-h urine calcium (uCa), serum bone turnover markers (s-CTX and P1NP), bone mineral density (BMD), and adverse events (AEs).

RESULTS

After 3 months,  ≥ 88% patients achieved independence from conventional therapy while mean ADsCa was maintained within target range (7.8-9 mg/dL). Eneboparatide induced a rapid and sustained reduction of mean 24-hour uCa, even among patients with hypercalciuria. Bone turnover markers slightly increased and BMD remained unchanged, consistent with progressive resumption of physiologic bone turnover. Eneboparatide was well tolerated with no serious AEs.

CONCLUSION

Eneboparatide allowed independence from conventional therapy and maintenance of serum calcium within a target range, while normalizing uCa excretion and producing a balanced resumption of bone turnover.

LBODP094 Living With An "Invisible Disease": A Qualitative Study With Patients With Hypoparathyroidism

Background

Hypoparathyroidism (HPT) is a rare condition in which the parathyroid glands fail to produce enough parathyroid hormone (PTH) or the PTH produced lacks biologic activity. The aim of this study was to explore the patient experience of HPT.

Methods

Adult patients with HPT, recruited via a medical recruitment agency and the US hypoPARAthyroidism Association, participated in web-based, semi-structured, qualitative interviews that were audio-recorded and transcribed. Thematic analysis identified key symptoms and health-related-quality-of-life (HRQOL) impacts of HPT.

Results

Interviews were conducted with 16 patients with self-reported HPT for ≥ 12 months (15 females; age range 26-76 years). Key HPT symptoms reported included: fatigue (n=16, 100%), cognitive dysfunction (n=15, 94%), pain (n=15, 94%), tingling (n=14, 88%), muscles twitches/spasms (n=13, 81%), muscle cramps (n=12, 75%), temperature sensitivity (n =12, 75%), muscles weakness (n=12, 75%), cardiovascular issues (n =10, 63%), and eye problems (n= 9, 56%). Patients experienced intra-day symptom variability and unpredictability depending on treatment (Tx) regime. This erratic symptom experience hindered daily planning, and interactions with family/friends, resulting in emotional distress. Patients reported that HPT had a detrimental impact on their daily lives including impacts on physical functioning (n=11, 69%), sleep (n=10, 63%), daily activities (n=16, 100%), and work (n=13, 81%) as well as on relationships and social functioning (n=16, 100%). Fifteen patients (94%) reported emotional impacts; a key issue was the patient-perceived "invisibility" of HPT, specifically patients’ disease experience was often dismissed by family/friends as HPT is rare, with "no visible" symptoms. Patients also noted the burden of HPT management (e. g., Tx regimens, potential effects from long-term medication use). The need for constant vigilance associated with symptoms monitoring and medication use could be onerous. The absence of "at-home calcium monitoring" required patients to adhere to self-imposed "medication timetables": any deviations caused emotional distress as patients feared triggering a "calcium crash". Seven patients noted that Tx effects were not sustained throughout the day, leading to a re-emergence of symptoms as the day progressed. Patients reported that symptom reduction, improved Tx longevity and at-home calcium self-monitoring were key factors that could improve wellbeing and HRQOL.

Conclusions

The interviews provided valuable insights on the patient lived experience of HPT. Patients’ lives were significantly disrupted by their HPT symptoms regardless of Tx regime. This disruption was exacerbated by the unpredictability of symptoms which challenged patients’ ability to live their lives. These findings highlight the need for durable effective Tx for patients with HPT.

Presentation: No date and time listed

Clinical Burden and Practice Patterns in Patients With Chronic Hypoparathyroidism in the United States (US): A Claims Data Analysis Using Diagnosis-Based Criteria

Objectives: Significant knowledge gaps exist regarding the comorbidities, treatment and lab testing patterns of patients with chronic hypoparathyroidism (cHP). This study describes a large cohort of patients with cHP identified using a diagnosis-based criteria from a claims database.

Methods: This retrospective cohort study was conducted using a large (130 million individuals) claims database (HealthVerity Closed Payer Claim Medical and Pharmacy databases: Private Source 20) from Oct 2014 to Dec 2019. Eligible patients had ≥2 diagnosis claims of HP (ICD9/10 codes: E20.0, E20.8, E20.9, 252.1) that were 6–15 months apart, a prescription claim for either active vitamin D, calcium, PTH or thyroid replacement therapy between the first qualifying HP claim and within 30 days of the second HP claim, and continuous enrollment for one year before the index date (the date of the first of two qualifying HP diagnosis claims) and ≥16 months after. Patients were followed up to two years after the index date. Patient characteristics, comorbidities, lab testing and treatment patterns were descriptively analyzed.

Results: Out of 43,640 patients with a diagnosis claim for HP, 4,118 patients met the eligibility criteria. The mean age of the cohort was 56.5 years + 18.6 (SD), and 76.4% were females, similar to data from other large cohort studies. The most common comorbidities during the 1-year follow-up were hypertension (56.0%), hypocalcemia (38.7%), cancer (30.5%, of which 24% were thyroid cancers), diabetes (29.4%), chronic pulmonary disease (24.1%), cardiac arrhythmias (17.4%), CKD stage 3–5 (17.0%), osteoporosis (9.6%) and neuropsychiatric disorders, including depressive disorders (22.0%), anxiety (21.6%), and sleep-wake disorders (18.4%). During the 1-year follow up, commonly monitored lab tests included serum calcium (89.9%), eGFR/creatinine (85.7%), 25-hydroxy vitamin D (61.1%), and intact PTH (43.9%). Remarkably, serum phosphorous (36.3%), serum magnesium (35.4%), and 24h-urine calcium (10.5%) were much less often monitored. In addition, BMD was measured in 10.9% patients. Also during the 1-year follow-up, 67.1% of patients had a prescription claim for thyroid replacement therapy, 60.5% for calcitriol, 15.7% for ergocalciferol, and 3.4 % for PTH.

Conclusion: Findings from this study highlight the high comorbidity burden in cHP patients which aligns with the monitoring patterns. Kidney function appears to be a key concern and may be important when considering therapeutic intervention. The comorbidities and practice patterns observed in this study are consistent with the results obtained using a surgery-based approach to identify cHP patients in the same claims database. Future studies will also examine the economic burden of cHP.

Clinical Burden and Practice Patterns in Patients With Chronic Hypoparathyroidism in the United States (US): A Claims Data Analysis Using Surgery-Based Criteria

Objectives: Significant knowledge gaps exist regarding the clinical burden and practice patterns associated with chronic hypoparathyroidism (cHP). This study assessed the clinical burden and practice patterns in patients with cHP identified using surgery-based criteria.

Methods: This retrospective cohort study was conducted using a large (130 million individuals) US claims database, the HealthVerity Closed Payer Claim Medical and Pharmacy database (Private Source 20) from Oct 2014 to Dec 2019. The patient eligibility criteria for the surgery-based method included the presence of a procedure claim of either parathyroidectomy, complete or partial thyroidectomy, or neck dissection, followed by a HP diagnosis claim (6–15 months apart) with a subsequent second HP diagnosis claim at any time point, and with continuous enrollment for 15 months before the index date (the date of the first qualifying HP diagnosis claim) and ≥6 months after. Patients were followed one year before the surgery and up to two years after the index date. Patient characteristics, comorbidities, laboratory testing and treatment patterns were descriptively analyzed.

Results: A total of 1,406 patients met the eligibility criteria, among which 1,184 patients had complete data for 1-year follow-up. The mean age was 52.1 + 16.4 (SD) years, and 83.2% were females. The mean time between surgery and qualifying HP diagnosis claim was 8.7 + 2.3 (SD) months, and 115 patients (8.2%) had a HP diagnosis prior to surgery. During the 1-year follow-up, the most common comorbidities were cancer (54.2%, of which 49% were thyroid cancers), hypertension (49.7%), hypocalcemia (47.1%), chronic pulmonary disease (21.9%), diabetes (21.7%), cardiac arrhythmias (18.4%), CKD stage 3–5 (11.3%), osteoporosis (9.8%), and neuropsychiatric disorders, including anxiety (23.9%), depressive disorders (21.8%), and sleep-wake disorders (20.9%). Most cHP patients were monitored for lab values. These included serum calcium (93.2%), eGFR/creatinine (86.2%), 25-Hydroxy Vitamin D (66.5%), intact PTH (63.0%), serum magnesium (40.9%), serum phosphorous (38.4%), bone mineral density (9.8%), and 24h-urine calcium (8.4%) during the 1-year follow up. Also within the 1-year follow-up, 66.9% of patients had a prescription claim for thyroid replacement therapy, 51.6% for calcitriol, 13.3% for ergocalciferol, and 5.5 % for PTH.

Conclusion: This cHP population, identified using surgery-based criteria, largely consists of patients with a recent diagnosis, and had a substantial comorbidity burden that aligned with the monitoring patterns. Already at this early stage of cHP, kidney function appears to be a key concern and may be important when considering therapeutic intervention. These data are consistent with our findings from a larger cHP population identified in the same database using a diagnosis-based approach.

A Single Administration of AZP-3601, a Novel, Long-Acting PTH Analog, Induces a Significant and Sustained Calcemic Response: Preliminary Data From a Randomized, Double-Blind, Placebo-Controlled Phase 1 Study

Hypoparathyroidism is a rare disease characterized by a deficiency in parathyroid hormone (PTH) that results in hypocalcemia and hyperphosphatemia. Current treatment approaches, including high dose oral calcium and active vitamin D, as well as recombinant human PTH (1–84), do not provide adequate or consistent control of either serum calcium or clinical symptoms over a full 24-hour period. AZP-3601 is a novel 36 amino-acid PTH analog that has been designed to potently bind to the R⁰ conformation of the PTH1 receptor, which results in prolonged signaling responses in vitro and prolonged calcemic responses in animals despite having a short circulating half-life. A Phase 1 double-blind, placebo-controlled, single and multiple ascending dose study is being conducted to evaluate the safety, tolerability and pharmacodynamics of AZP-3601 in healthy adults. Here we report data from the first cohorts of the single ascending dose portion of the study. Sequential cohorts of 4 (cohort 1) to 8 (cohort 2 to 4) healthy male subjects aged 18–60 years, with a body mass index of 19–28 kg/m², were assigned to receive 5, 10, 20 or 40μg of AZP-3601 or placebo at a ratio of 3:1. The study drug was administered in the morning by subcutaneous injection in the abdominal wall and was well tolerated with no remarkable adverse events. As compared with placebo controls, AZP-3601 treatment produced a clear, dose-dependent increase in mean albumin-adjusted serum calcium values from baseline. The normal physiological diurnal variation of albumin-adjusted serum calcium was gradually attenuated with 5 and 10μg AZP-3601, and was completely eliminated with 20μg. With the dose of 40μg AZP-3601, mean albumin-adjusted serum calcium values were significantly increased but stayed within normal laboratory range and remained elevated through at least 24 hours post-administration. We observed a dose-dependent decrease in mean endogenous serum PTH that was significantly correlated with the concomitant increase in mean serum calcium. These data provide initial evidence of the pharmacodynamic effect of AZP-3601 in healthy humans characterized by a sustained calcemic response for at least 24 hours following a single administration.

SUN-609 Livoletide (AZP-531), an Unacylated Ghrelin Analogue, Improves Hyperphagia and Food-Related Behaviors Both in Obese and Non-Obese People with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare, complex neuro-developmental genetic disorder characterized by hyperphagia and abnormal food-related behaviors that contribute to severe morbidity and early mortality and to significant burden on patients and caregivers. While a majority of people with PWS is obese, hyperphagia is observed in both obese and non-obese people with PWS. There is currently no approved treatment for hyperphagia in PWS. People with PWS have increased circulating levels of the orexigenic hormone acylated ghrelin (AG) with a relative deficit of unacylated ghrelin (UAG), a hormone which counteracts many of AG’s effects. Livoletide (AZP-531) is a first-in-class UAG analogue previously shown to improve hyperphagia, food-related behaviors, and metabolic parameters, and to be well-tolerated in a Phase 2a trial in PWS. [Allas S et al. (2018) PLoS ONE 13(1): e0190849] Here we present additional analyses that examine the effects of livoletide in obese vs non-obese people with hyperphagia in PWS.

Methods: The Phase 2a trial was a randomized, double-blind, placebo-controlled study which included 47 people with PWS. Participants received a daily subcutaneous injection of livoletide (n=23) or placebo (n=24) during a 2-week treatment period. The study population was divided based on the body mass index (BMI) into obese (BMI ≥ 30 kg/m²) and non-obese (BMI < 30 kg/m²) groups. The effect of livoletide on hyperphagia and food-related behaviors was assessed by the change from baseline in the 9-item Hyperphagia Questionnaire (HQ).

Results: There was a total of 34 obese and 13 non-obese subjects in the study. As expected, baseline BMI, body weight (BW) and waist circumference (WC) were significantly higher in obese vs. non-obese PWS subjects (BMI: 42.6 ± 6.0 vs 26.1 ± 2.8, BW: 103.5 ± 23.0 vs 68.5 ± 9.1 and WC: 118.3 ± 15.5 vs 91.8 ± 7.7, respectively, p<0.0001). There was no significant difference with respect to the ratios of males to females or of deletion to non-deletion between the 2 populations. Hyperphagia scores were similar at baseline for obese and non-obese participants (HQ score adjusted for 0 to 36 scale to reflect 9-item HQ-CT: 12.8 ± 7.0 vs 14.0 ± 7.8, p=0.6083, respectively). Fasting AG and UAG levels were lower in the obese vs. non-obese groups (AG: 93.6 ± 72.6 vs 122.1 ± 54.4, p=0.0275, UAG: 123.9 ± 87.2 vs 154.1 ± 62.6, p=0.0219, respectively). Livoletide-treated participants experienced similar improvements in hyperphagia and food-related behaviors as measured by the HQ whether they were obese or non-obese.

Conclusions: These results highlight the potential of livoletide for treating hyperphagia in both obese and non-obese people with PWS and hyperphagia. Livoletide is being investigated further in the ZEPHYR Phase 2b/3 trial, an ongoing pivotal study on the long-term safety and efficacy of livoletide in the treatment of hyperphagia and food-related behaviors in people with PWS.

MON-102 Nonclinical Development of AZP-531 (Livoletide): A Peptide Analog of Unacylated Ghrelin for the Treatment of Hyperphagia in Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare and complex endocrine disease characterized by hyperphagia and abnormal food-related behaviors that contribute to severe morbidity and early mortality and to a significant burden on patients and caregivers. Hyperghrelinemia may be involved in the underlying mechanisms of hyperphagia. While ghrelin, the most potent appetite-stimulating hormone, is present at higher concentrations in the plasma of PWS patients compared to age-matched controls, detailed studies of ghrelin and unacylated ghrelin (UAG) reveal a relative deficit of UAG in hyperphagic individuals. UAG is a 28-amino-acid peptide that does not bind the growth hormone secretagogue receptor (GHSR), in contrast to acylated ghrelin. UAG has intrinsic activities that often counteract effects of ghrelin, and exerts its actions through a GHSR-independent mechanism. Livoletide is a cyclic 8-amino-acid analogue of UAG with improved plasma stability and pharmacokinetics. The objective of this nonclinical safety program was to support the clinical development of livoletide including a pivotal Phase 2b/3 clinical trial in patients with PWS. The program was designed to define the safety pharmacology and the chronic toxicologic and toxicokinetic profile, and identify parameters for clinical monitoring of potential adverse effects. Genotoxicity, safety pharmacology, reproductive toxicity, and repeat-dose 13-week toxicology studies were all completed. In the in vivo studies, livoletide was administered subcutaneously consistent with the clinical route of delivery. Livoletide was not cytotoxic or genotoxic. Safety pharmacology studies indicated no treatment-related effects on major physiological systems. Results from preliminary embryo-fetal developmental toxicity studies in rat and rabbit indicated that livoletide at high multiples of the anticipated human exposure is not associated with adverse maternal toxicity, embryo-fetal toxicity or teratogenic potential when administered throughout the period of organogenesis. Repeat-dose toxicity studies of up to 13 weeks’ duration in rats and dogs demonstrated that livoletide is very well-tolerated, with no evidence of systemic toxicity. Cumulative data indicated that livoletide has a wide safety margin relative to planned clinical exposures. The highest chronic doses tested were 75 mg/kg in rat and 30 mg/kg in dog; these were considered to be the NOAELs. These dose levels provided AUC values of ≥50-fold the intended clinical systemic exposure (~1200 ng·h/mL). No anti-livoletide antibodies were detected in any of the toxicology studies. These results confirm the favorable long-term safety profile of livoletide and support the subcutaneous administration of the highest anticipated human clinical dose in the Phase 2b/3 study.

SAT-100 Trial-in-Progress: ZEPHYR, a Pivotal Phase 2b/3 Randomized, Placebo-Controlled Study of Livoletide, a Novel Unacylated Ghrelin Analog, for the Treatment of Hyperphagia and Food-Related Behaviors in Patients with Prader-Willi Syndrome

Background: Prader-Willi syndrome (PWS) is a rare and complex endocrine disease characterized by hyperphagia and abnormal food-related behaviors that contribute to severe morbidity and early mortality and to a significant burden on patients and caregivers. There is no approved treatment for hyperphagia in PWS. Patients with PWS have increased circulating levels of the orexigenic hormone acylated ghrelin (AG) with a relative deficit of unacylated ghrelin (UAG). Livoletide (AZP-531) is a first-in-class UAG analog that was previously shown in a Phase 2 randomized placebo-controlled study in a 47-patient PWS cohort to significantly improve hyperphagia, food related behaviors, and metabolic parameters and to be well-tolerated with no serious adverse events or treatment discontinuations over a 14-day period. [Allas S et al. (2018) PLoS ONE 13(1): e0190849] Objective: ZEPHYR (EudraCT 2018-003062-13) is a pivotal Phase 2b/3 study that is designed to evaluate the long-term safety and efficacy of livoletide in patients with PWS. Methods: The ZEPHYR study will be conducted in centers in North America and Europe. In its Phase 2b portion, approximately 150 patients with PWS will be randomized in a 1:1:1 ratio to receive livoletide low exposure (8 mg/mL), livoletide high exposure (16 mg/mL), or placebo, once a day by sc injection for a three-month core period. Then, patients who received placebo will cross over to livoletide low or high exposure and be treated for 9 months. Patients who received livoletide will continue at their original dose for an additional 9 months. The Phase 3 portion will be initiated following results of the Phase 2b core period with patients randomized 1:1 to livoletide at a dose based on Phase 2b core data or to placebo for a six-month duration. Subsequently, patients who received placebo will be crossed over to livoletide for six months, while patients on livoletide initially will continue for six more months. Main entry criteria for ZEPHYR include genetic diagnosis of PWS, age 8-65 years, single primary caregiver available for the duration of the study, BMI ≤65 kg/m² for adult patients. Patients with type 2 diabetes with HbA1C ≤10% and stable therapy may be enrolled. Use of human growth hormone will be allowed if dosage is stable. Patients enrolled in Phase 2b will not be eligible for Phase 3. The primary outcome measure is the Hyperphagia Questionnaire-Clinical Trials (HQ-CT) score. The HQ-CT has been validated and is considered by regulatory authorities as a valid primary endpoint. Secondary outcome measures include fat mass as assessed by DEXA, BMI, and body weight in overweight/obese patients. Results: The study is ongoing: enrollment began in early 2019 and an updated status will be reported. Conclusion: ZEPHYR is a pivotal study that will provide data on the long-term safety and efficacy on hyperphagia and food-related behaviors of the novel UAG analog livoletide in patients with PWS.

Safety, tolerability, pharmacokinetics and pharmacodynamics of AZP-531, a first-in-class analogue of unacylated ghrelin, in healthy and overweight/obese subjects and subjects with type 2 diabetes

AIM

To explore the safety, pharmacokinetics and pharmacodynamics in humans of the unacylated ghrelin analogue AZP-531, designed to improve glycaemic control and reduce weight.

METHODS

Assessments, including glucose measurements, were performed in a three-part randomized study. In Part A, healthy subjects [n = 44, age 18-50 years, body mass index (BMI) 20-28 kg/m(2) ] received a single subcutaneous dose of 0.3, 3, 15, 30, 60 or 120 µg/kg AZP-531 or placebo. In Part B, overweight/obese subjects (n = 32, age 18-65 years, BMI 28-38 kg/m(2) ) and in Part C, patients with type 2 diabetes [T2D; n = 36, age 18-65 years, BMI 20-40 kg/m(2) , glycated haemoglobin (HbA1c) 7-10%] received AZP-531 or placebo for 14 days (daily doses of 3, 15, 30 or 60 µg/kg and 15, 2 × 30 or 60 µg/kg, respectively).

RESULTS

AZP-531 was well tolerated. Single- and multiple-dose pharmokinetic variables were similar. Maximum AZP-531 concentrations were typically reached at 1 h post-dose. Observed maximum concentration (Cmax ) and area under the curve were dose-proportional. The mean terminal half-life (t1/2 ) was 2-3 h. In Part B, AZP-531 doses of ≥15 µg/kg significantly improved glucose concentrations, without increasing insulin levels, suggesting an insulin-sensitizing effect. AZP-531 decreased mean body weight by 2.6 kg (vs 0.8 kg for placebo). In Part C, glucose variables improved in all groups, including placebo, suggesting a study effect in uncontrolled patients at baseline. Notwithstanding, AZP-531 60 µg/kg reduced HbA1c by 0.4% (vs 0.2% for placebo) and body weight by 2.1 kg (vs 1.3 kg for placebo).

CONCLUSIONS

AZP-531 was well tolerated in this first-in-human study. Its pharmacokinetic profile, suitable for once-daily dosing, and metabolic effects support further clinical development for T2D.

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2-29.4 years) and compared with 50 age-matched obese subjects (4.3-16.9 years) and 39 healthy controls (0.8-28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.

Differential mechanisms of asparaginase resistance in B-type acute lymphoblastic leukemia and malignant natural killer cell lines

Bacterial L-asparaginase (ASNase), hydrolyzing L-asparagine (Asn), is an important drug for treating patients with acute lymphoblastic leukaemia (ALL) and natural killer (NK) cell lymphoma. Although different native or pegylated ASNase-based chemotherapy are efficient, disease relapse is frequently observed, especially in adult patients. The neo-synthesis of Asn by asparagine synthetase (AsnS) following ASNase treatment, which involves the amino acid response and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathways, is believed to be the basis of ASNase-resistance mechanisms. However, AsnS expression has not emerged as an accurate predictive factor for ASNase susceptibility. The aim of this study was to identify possible ASNase sensitivity/resistance-related genes or pathways using a new asparaginase, namely a pegylated r-crisantaspase, with a focus on classic Asn-compensatory responses and cell death under conditions of Asn/L-glutamine limitation. We show that, for B-ALL cell lines, changes in the expression of apoptosis-regulatory genes (especially NFκB-related genes) are associated with ASNase susceptibility. The response of malignant NK cell lines to ASNase may depend on Asn-compensatory mechanisms and other cellular processes such as cleavage of BCL2A1, a prosurvival member of the Bcl-2 protein family. These results suggest that according to cellular context, factors other than AsnS can influence ASNase susceptibility.

Does des-acyl ghrelin improve glycemic control in obese diabetic subjects by decreasing acylated ghrelin levels?

OBJECTIVE

The objective of this study was to assess the effects of a continuous overnight infusion of des-acyl ghrelin (DAG) on acylated ghrelin (AG) levels and glucose and insulin responses to a standard breakfast meal (SBM) in eight overweight patients with type 2 diabetes. Furthermore, in the same patients and two additional subjects, the effects of DAG infusion on AG concentrations and insulin sensitivity during a hyperinsulinemic-euglycemic clamp (HEC) were assessed.

RESEARCH DESIGN AND METHODS

A double-blind, placebo-controlled cross-over study design was implemented, using overnight continuous infusions of 3 and 10  μg DAG/kg per h and placebo to study the effects on a SBM. During a HEC, we studied the insulin sensitivity.

RESULTS

We observed that, compared with placebo, overnight DAG administration significantly decreased postprandial glucose levels, both during continuous glucose monitoring and at peak serum glucose levels. The degree of improvement in glycemia was correlated with baseline plasma AG concentrations. Concurrently, DAG infusion significantly decreased fasting and postprandial AG levels. During the HEC, 2.5  h of DAG infusion markedly decreased AG levels, and the M-index, a measure of insulin sensitivity, was significantly improved in the six subjects in whom we were able to attain steady-state euglycemia. DAG administration was not accompanied by many side effects when compared with placebo.

CONCLUSIONS

DAG administration improves glycemic control in obese subjects with type 2 diabetes through the suppression of AG levels. DAG is a good candidate for the development of compounds in the treatment of metabolic disorders or other conditions with a disturbed AG:DAG ratio, such as type 2 diabetes mellitus or Prader-Willi syndrome.

Clinical perspectives for ghrelin-derived therapeutic products

Because of its orexigenic, adipogenic and diabetogenic activities, acylated ghrelin (AG) has emerged as an attractive target for the treatment of obesity and type 2 diabetes. Pharmacological tools have been designed in order to antagonize or block the hormone's activity, or inhibit ghrelin O-acyltransferase (GOAT), the enzyme that catalyzes its acylation. AG antagonists, shown to be potent inhibitors of growth hormone (GH) secretion, were not able to consistently induce the desirable metabolic effects. Some of them, on the contrary, acted as AG agonists. Similarly, AG-blocking agents including Spiegelmers, vaccines, and monoclonal antibodies, gave mixed results. More encouraging yet very preliminary data were obtained with a novel GOAT inhibitor. However, although significant, the observed decrease in circulating AG levels was partial and improvement work remains to be done. Unacylated ghrelin (UAG) and analogs were shown to potently and rapidly inhibit plasma AG levels, and to improve glucose metabolism in addition to displaying beneficial effects on a variety of cells. These data support the rationale for further development of this new therapeutic class in type 2 diabetes and the Prader-Willi syndrome. A development program is underway with AZP-531, a cyclized UAG(6-13) analog with improved pharmacokinetic properties.

In vitro and in vivo stability and pharmacokinetic profile of unacylated ghrelin (UAG) analogues

Ghrelin, an endocrine hormone predominantly produced by the stomach, exists in acylated and unacylated forms in the circulation. Unacylated ghrelin (UAG), the more abundant form in blood, possesses similar, independent or opposite physiological actions as acylated ghrelin (AG). AZP502, a linear 8-amino acid peptide from the central region of UAG (UAG(6-13)), and its full (AZP531) and partially (AZP533) cyclised derivatives, exhibit the same pharmacological profile as UAG both in vitro and in vivo, independently of AG receptor binding. We investigated the stability of these three fragments in vitro in human blood samples and in vivo after subcutaneous and intravenous injection in rats and dogs using liquid chromatography-mass spectrometry. In both species, AZP502 is rapidly degraded generating two major metabolites. Partial cyclisation of AZP502 and acylation at its N-terminus (AZP533 peptide) improves its stability in human plasma in vitro. Full cyclisation of AZP502 (AZP531 peptide) also completely protects the peptide from peptidase degradation in vitro in human blood samples. Moreover this cyclisation strongly improves the stability and the bioavailability of this peptide in vivo in both dogs and rats (mean bioavailability of 10-15% and 85-95% for AZP502 and AZP531 respectively). Taken together these results support the rationale for developing AZP531 as a long-acting UAG analogue for subcutaneous injection for the treatment of type 2 diabetes mellitus and other metabolic disorders.

Metabolic effects of a growth hormone-releasing factor in patients with HIV

BACKGROUND

Visceral adipose tissue accumulates during antiretroviral therapy in many patients who are infected with the human immunodeficiency virus (HIV); this process is associated with an increased cardiovascular risk. We assessed the use of a growth hormone-releasing factor analogue, tesamorelin, to decrease visceral adiposity.

METHODS

We randomly assigned 412 patients with HIV (86% of whom were men) who had an accumulation of abdominal fat to receive a daily subcutaneous injection of either 2 mg of tesamorelin or placebo for 26 weeks. The primary end point was the percent change from baseline in visceral adipose tissue as shown on computed tomography. Secondary end points included triglyceride levels, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, the level of insulin-like growth factor I (IGF-I), and self-assessed body image. Glycemic measures included glucose and insulin levels.

RESULTS

The measure of visceral adipose tissue decreased by 15.2% in the tesamorelin group and increased by 5.0% in the placebo group; the levels of triglycerides decreased by 50 mg per deciliter and increased by 9 mg per deciliter, respectively, and the ratio of total cholesterol to HDL cholesterol decreased by 0.31 and increased by 0.21, respectively (P<0.001 for all comparisons). Levels of total cholesterol and HDL cholesterol also improved significantly in the tesamorelin group. Levels of IGF-I increased by 81.0% in the tesamorelin group and decreased by 5.0% in the placebo group (P<0.001). Adverse events did not differ significantly between the two study groups, but more patients in the tesamorelin group withdrew from the study because of an adverse event. No significant differences were observed in glycemic measures.

CONCLUSIONS

Daily tesamorelin for 26 weeks decreased visceral fat and improved lipid profiles, effects that might be useful in HIV-infected patients who have treatment-associated central fat accumulation. (ClinicalTrials.gov number, NCT00123253 [ClinicalTrials.gov] .).

A placebo-controlled, dose-ranging study of a growth hormone releasing factor in HIV-infected patients with abdominal fat accumulation

OBJECTIVE

To investigate the effects of TH9507, a novel growth hormone releasing factor, on abdominal fat accumulation, metabolic and safety parameters in HIV-infected patients with central fat accumulation.

DESIGN AND METHODS

Randomized, double-blind, placebo-controlled trial enrolling 61 HIV-infected patients with increased waist circumference and waist-to-hip ratio. Participants were randomized to placebo or 1 or 2 mg TH9507 subcutaneously, once daily for 12 weeks. The primary outcome was change in abdominal fat, assessed by dual energy X-ray absorptiometry and cross-sectional computerized tomography scan. Secondary endpoints included change in insulin-like growth factor-I (IGF-I), metabolic, quality of life, and safety parameters.

RESULTS

TH9507 resulted in dose-related physiological increases in IGF-I (P < 0.01 for 1 mg (+48%) and 2 mg (+65%) versus placebo). Trunk fat decreased in the 2 mg group versus placebo (0.8, -4.6 and -9.2%; placebo, 1 and 2 mg, respectively, P = 0.014 for 2 mg versus placebo), without significant change in limb fat. Visceral fat (VAT) decreased most in the 2 mg group (-5.4, -3.6 and -15.7%; placebo, 1 and 2 mg, respectively) but this change was not significant versus placebo. Subcutaneous fat (SAT) was preserved and did not change between or within groups. Lean body mass and the ratio of VAT to SAT improved significantly in both treatment groups versus placebo. Triglyceride and the cholesterol to high-density lipoprotein ratio decreased significantly in the 2 mg group versus placebo. Treatment was generally well tolerated without changes in glucose.

CONCLUSIONS

TH9507 reduced truncal fat, improved the lipid profile and did not increase glucose levels in HIV-infected patients with central fat accumulation. TH9507 may be a beneficial treatment strategy in this population, but longer-term studies with more patients are needed to determine effects on VAT, treatment durability, and safety.

Comparison of UVA protection afforded by high sun protection factor sunscreens

UVA protection afforded by 6 different sunscreens with a sun protection factor of 21 or more was compared by means of the persistent pigmentation darkening method. Colorimetric and visual assessment showed significant differences in UV radiation-induced pigmentation at 2 hours. The labeled sun protection factor of the tested sunscreens was not predictive of UVA protection level.

Healing of experimental aneurysms. II: Platelet extracts can increase the thickness of the neointima at the neck of treated aneurysms

PURPOSE

To assess the effect of platelet extracts (PE) on neointima formation following gelfoam packing of experimental porcine aneurysms. A strategy involving the local delivery of platelet growth factors may potentially improve long term results of endovascular treatment of aneurysms.

METHODS

Bilateral lateral wall common carotid aneurysms were constructed on 30 pigs. A collagen sponge containing a PE rich in growth factors was used to pack one aneurysm with the controlateral lesion being embolized with a sponge containing NaCl 0.9% (22 animals). In 8 animals, a control sponge was used on both sides. Animals were sacrificed at 1, 2, 3, 4 and 9 weeks and the thickness of the neointima covering the neck of PE-treated aneurysms was measured in 5 locations for each lesion at 2 and 3 weeks and compared with the control aneurysm of the same animal. Morphometric data was analysed using the paired Student's t-test.

RESULTS

The thickness of the neointima was significantly increased in lesions treated with PE as compared to control lesions at 2 weeks (p = 0.008, n = 9). There was no significant difference at 3 weeks (p = 0.99, n = 9). There was no significant difference between lesions of control animals (p = 0.95, n = 8).

CONCLUSION

PE rich in growth factors can increase the thickness of the neointima at the neck of treated experimental porcine aneurysms at 2 weeks, but had no effect at 3 weeks. This accelerated neointimal formation may have some value in improving healing following endovascular treatment. This hypothesis could not be supported with this experimental model which has a spontaneous tendency to heal. Further studies using an animal model which reproduces the clinical problem of recurrences may help to define the role of the local delivery of growth factors in combination with coils in a strategy designed to improve results of endovascular treatment.

Healing mechanisms in experimental aneurysms. I. Vascular smooth muscle cells and neointima formation

PURPOSE

The purpose of this work is to better define healing phenomena in this model, in an effort to find strategies to improve long term results of endovascular treatment.

METHODS

Lateral wall venous pouch aneurysms were constructed on both carotid arteries in 30 pigs. The aneurysms were packed with collagen sponges per-operatively in 25 animals. Angiography, serial histological studies and immuno-histochemistry tests were used to study healing phenomena and measure neointima formation at various time intervals from 1 day to 9 weeks after surgery. GDC embolization was performed in 5 other pigs for comparison with the collagen sponge model. Explants from the neointima at the neck of aneurysms as well as from the parent artery of 8 pigs were prepared in an attempt to grow and to characterize in vitro cells responsible for healing porcine aneurysms using immunocytochemistry and enzymatic assays. To confirm the hypothesis that an analogy exists between cells involved in aneurysmal healing and neointimal cells found in restenosis, explant outgrowths were scored and compared to explants from intact carotid arteries and carotid arteries subjected to angioplasty in 3 other animals. In addition, to test the value of neointima measurements in quantifying results, 6 dogs were analysed to correlate the thickness of the neointima formed at the neck of aneurysms with angiographic results in animals prone to recurrences.

RESULTS

Histopathological findings with collagen sponge packing were similar to the ones following coil embolization. Porcine aneurysms had a strong tendency to heal with a thick neointima primarily composed of vascular smooth muscle cells (VSMCs). Aneurysms in dogs did not heal as well and the neointima at the neck of treated lesions was thin. Cells responsible for healing of experimental porcine aneurysms could be cultured in vitro, and are activated VSMCs. These cells, similar to those harvested following balloon injury, had a higher colony forming capacity and an accelerated explant outgrowth rate as compared to cells derived from the parent artery.

CONCLUSION

Animals which heal poorly harbor a thin or deficient neointima at the neck of treated aneurysms. Favorable healing in porcine aneurysms involves VSMCs which form a thick neointima. These VSMCs can be cultured in vitro. They share similar outgrowth characteristics with VSMCs recovered after balloon angioplasty. The collagen sponge model may be useful to harvest cells for in vitro experimentation and in the in vivo evaluation of the local delivery of potential therapeutic molecules thought to improve healing following embolization of aneurysms.