Tirzepatide in Hispanic/Latino Patients With Type 2 Diabetes: A Subgroup Analysis of the SURPASS Program.

CONTEXT: Efficacy and safety of tirzepatide, a once-weekly glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist, have been studied in patients with type 2 diabetes in the global phase 3 SURPASS program. OBJECTIVE: This work aimed to assess the efficacy and safety of tirzepatide in Hispanic/Latino and non-Hispanic/Latino patients in SURPASS-1 to -4 clinical trials. METHODS: A total of 5679 patients were included, 2895 of self-reported Hispanic/Latino ethnicity, in this exploratory analysis of SURPASS-1 to -4 trial data. Interventions included tirzepatide 5, 10, or 15 mg, placebo, or active comparator (semaglutide 1 mg, insulin degludec, and insulin glargine). Change in glycated hemoglobin A1c (HbA1c) and body weight from baseline to week 40 (SURPASS-1 and -2) and to week 52 (SURPASS-3 and -4), and other efficacy and safety outcomes were evaluated within Hispanic/Latino and non-Hispanic/Latino subgroups. RESULTS: Among Hispanic/Latino and non-Hispanic/Latino patients treated with tirzepatide, respectively, HbA1c decreased significantly from baseline, ranging from 1.9% to 2.7% and 1.7% to 2.5%, and body weight decreased significantly from baseline, ranging from 5.3 kg to 12.4 and 6.5 kg to 17.1 kg (both P < .05) vs comparators across all trials. Subgroup trends were consistent with the overall trial populations. Treatment-emergent adverse events were reported in similar proportions across the subgroups and were primarily gastrointestinal disorders. The incidence of hypoglycemia was low. CONCLUSION: Tirzepatide significatively reduced HbA1c and body weight in Hispanic/Latino and non-Hispanic/Latino patients. Tirzepatide was generally well tolerated in both subgroups. Efficacy and safety trends were comparable between subgroups and within the overall trial populations.

Physician Perceptions of Dose Escalation for Type 2 Diabetes Medications in the United States.

INTRODUCTION: Medications used to treat type 2 diabetes (T2D) often require dose escalation to optimize effectiveness. Physician and patient perceptions of treatment characteristics of T2D medications have previously been examined, but little is known about perceptions of escalation to the optimal dose for each patient. This study examined physicians' perceptions of dose escalation for medications used to treat T2D. METHODS: Data on dose escalation and other factors influencing decision-making for treatment of T2D were collected via an online survey of endocrinologists and primary care physicians in the USA. RESULTS: The sample included 501 physicians (348 primary care physicians and 153 endocrinologists). Dose escalation was not frequently considered by physicians as a primary factor keeping patients' from reaching treatment goals (mentioned as a factor by only 7.6% of the sample) or a barrier to prescribing T2D medication (16.2%). Factors more likely to keep patients from reaching treatment goals included an unhealthy diet (86.6%) and medication adherence (77.4%). The most common reasons that physicians reported for escalating dose levels were the need for better glycemic control (reported by 89.8% of the sample), ability to decrease the total number of medications by increasing the dose of one medication (39.9%), and the need for the patient to lose weight (39.3%). Data reported by primary care physicians and endocrinologists followed similar patterns. CONCLUSIONS: Although common with T2D treatments, escalating the dose of T2D medication was not perceived by physicians to be a significant barrier to attaining treatment goals or prescribing medication. Multiple factors contribute to the decision to escalate the dose of T2D medication.

In early phases of initiating medication treatment for a patient with type 2 diabetes (T2D), it is common for physicians to increase from a lower initial dose to a higher end dose to maximize treatment benefit. This process is known as dose escalation. The purpose of this study was to examine physicians' perceptions of dose escalation for medications used to treat T2D. An online survey was designed to identify reasons why physicians in the US may choose to escalate or not escalate a dose of medication for T2D. In addition, physicians were asked about factors that keep patients from reaching treatment goals to identify whether the requirement for dose escalation is perceived to be a common barrier to successful treatment. The sample included 501 physicians (348 primary care, 153 endocrinologists). Dose escalation was not frequently considered to be a primary factor keeping patients' from reaching treatment goals or a barrier to prescribing medication for T2D. Dose escalation decisions are complex, driven by a range of factors such as glycemic control medication tolerability, the patient's body mass index, treatment guidelines, comorbidities, characteristics of the patient's entire treatment regimen, and potential cardiovascular benefits.

Dulaglutide and Kidney Function-Related Outcomes in Type 2 Diabetes: A REWIND Post Hoc Analysis.

OBJECTIVE: Dulaglutide (DU) 1.5 mg was associated with improved composite renal outcomes that included new-onset macroalbuminuria in people with type 2 diabetes with previous cardiovascular disease or cardiovascular risk factors in the REWIND (Researching cardiovascular Events with a Weekly INcretin in Diabetes) trial. This exploratory post hoc analysis evaluated kidney function-related outcomes, excluding the new-onset macroalbuminuria component, among the REWIND participants. RESEARCH DESIGN AND METHODS: Intent-to-treat analyses were performed on REWIND participants (n = 4,949 DU, n = 4,952 placebo). Time to occurrence of a composite kidney function-related outcome (≥40% sustained decline in estimated glomerular filtration rate [eGFR], per the Chronic Kidney Disease Epidemiology Collaboration 2009 equation, end-stage renal disease, or renal-related death), and mean annual eGFR slope were examined. Analyses were conducted overall and within subgroups defined by baseline urinary albumin-to-creatinine ratio (UACR <30 or ≥30 mg/g) and baseline eGFR (<60 or ≥60 mL/min/1.73 m2). RESULTS: The post hoc composite kidney function-related outcome occurred less frequently among participants assigned to DU than placebo (hazard ratio [HR] 0.75, 95% CI 0.62-0.92, P = 0.004), with no evidence of a differential DU treatment effect by UACR or eGFR subgroup. A ≥40% sustained eGFR decline occurred less frequently among participants assigned to DU than placebo (HR 0.72, 95% CI 0.58-0.88, P = 0.002). The mean annual decline in eGFR slope was significantly smaller for participants assigned to DU than placebo (-1.37 vs. -1.56 mL/min/1.73 m2/year, P < 0.001); results were similar for all subgroups. CONCLUSIONS: The estimated 25% reduced hazard of a kidney function-related outcome among participants assigned to DU highlights its potential for delaying or slowing the development of diabetic kidney disease in people with type 2 diabetes.

Tirzepatide 10 and 15 mg compared with semaglutide 2.4 mg for the treatment of obesity: An indirect treatment comparison.

AIM: To compare the efficacy of tirzepatide 10 and 15 mg with semaglutide 2.4 mg using an indirect treatment comparison. MATERIALS AND METHODS: Using SURMOUNT-1 and STEP 1 trial data, mean percentage change in body weight from baseline and odds ratio (OR) of achieving 5% or greater weight loss were compared between tirzepatide 10 and 15 mg at week 72 and semaglutide 2.4 mg at week 68 using matching-adjusted indirect comparison of the efficacy estimand. Sensitivity analyses were completed using different methods, including the Bucher method, also using different estimands and/or time points. RESULTS: Greater reductions in percentage change in body weight were observed with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg (tirzepatide 10 mg mean difference: -4.67% [95% CI -5.91%, -3.43%]; tirzepatide 15 mg mean difference: -5.92% [95% CI -7.16%, -4.68%]; both P < .001). Similarly, more participants achieved 5% or greater weight loss with tirzepatide 10 mg (OR 2.61 [95% CI 1.48, 4.57]; P < .001) and 15 mg (OR 2.75 [95% CI 1.57, 4.81]; P < .001) compared with semaglutide 2.4 mg. All sensitivity analyses were consistent, except for an OR of achieving 5% or greater weight loss with tirzepatide 10 mg using the Bucher method to analyse the treatment regimen estimand (P = .074). CONCLUSIONS: Currently there are no direct comparisons of tirzepatide and semaglutide for weight management. Using the matching-adjusted indirect treatment comparison method to compare the efficacy of tirzepatide and semaglutide for chronic weight management, this analysis showed greater weight loss with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg.

Greater Adherence and Persistence with Injectable Dulaglutide Compared with Injectable Semaglutide at 1-Year Follow-up: Data from US Clinical Practice.

PURPOSE: Greater medication adherence and persistence have been associated with improved glycemic control in patients with type 2 diabetes mellitus. This study compared adherence, persistence, and treatment patterns among patients naïve to glucagon-like peptide 1 receptor agonists initiating once-weekly injectable treatment with dulaglutide versus semaglutide over 6-month (6M) and 12-month (12M) follow-up periods. METHODS: This retrospective, observational cohort study used administrative claims data from three IBM MarketScan research databases. Data from adult patients with type 2 diabetes newly initiating treatment with dulaglutide or semaglutide between January 2018 and January 2020 (index date was defined as the earliest fill date), without evidence of glucagon-like peptide 1 receptor agonist use in the 6M baseline period, and with continuous enrollment in the 6M baseline and 6M or 12M follow-up period were included. Dulaglutide initiators were propensity score-matched, in a 1:1 ratio, to semaglutide initiators in each 6M and 12M follow-up cohort (26,284 and 13,837 pairs, respectively). FINDINGS: In the matched cohorts, baseline characteristics were balanced; the mean age was 53 years, and 50% of patients were women. Compared to semaglutide initiators, dulaglutide initiators were more adherent (6M, 63.4% vs 47.8%; 12M, 54.4% vs 43.3%; both, P < 0.0001), more persistent on therapy (6M, 72% vs 62%, 12M, 55.5% vs 45.3%, both, P < 0.001), and had more mean days of persistence (6M, 145 vs 132, 12M, 254.3 vs 220.7; both, P < 0.001). IMPLICATIONS: At both 6M and 12M follow-up, dulaglutide initiators had significantly greater adherence and greater persistence compared with matched semaglutide initiators.

Glycaemic efficacy of an expanded dose range of dulaglutide according to baseline glycated haemoglobin (HbA1c) subgroup: Post hoc analysis of AWARD-11.

The AWARD-11 trial demonstrated the safety and efficacy of dulaglutide 3.0 and 4.5 mg compared to dulaglutide 1.5 mg in patients with type 2 diabetes inadequately controlled with metformin. This post hoc analysis examined the change from baseline in glycated haemoglobin (HbA1c) and proportions of patients achieving HbA1c <7% at weeks 36 and 52 with dulaglutide 1.5 mg, 3.0 mg or 4.5 mg across clinically relevant baseline HbA1c subgroups (<8%; 8.0% to < 9.0%; 9.0% to < 10%; and ≥ 10%). Mean reductions in HbA1c were observed across all baseline HbA1c subgroups at 36 weeks (range of HbA1c change: 1.5 mg: -1.0% to -2.2%; 3.0 mg: -1.2% to -2.5%; and 4.5 mg: -1.2% to -3.2%). More patients randomized to 3.0 mg or 4.5 mg (vs. 1.5 mg) achieved HbA1c <7% at 36 weeks regardless of baseline HbA1c; the difference in proportions was greater at higher baseline HbA1c (P-interaction = 0.096). Similar patterns in glycaemic improvement and proportions achieving HbA1c <7% were observed at 52 weeks. Hypoglycaemia and gastrointestinal adverse events were similar among the HbA1c subgroups. Glycaemic control was improved with dulaglutide dose escalation from 1.5 mg to 3.0 mg or 4.5 mg across baseline HbA1c subgroups (<8%; 8.0% to < 9.0%; 9.0% to < 10%; and ≥ 10%).

Patient Perceptions of and Preferences Between Characteristics of Injectable Diabetes Treatments.

INTRODUCTION: The administration of medications targeting type 2 diabetes mellitus (T2D) has evolved over time. As injection delivery systems continue to evolve, it is necessary to understand patients' perceptions of currently available treatments. The objective of this study was to examine the patient perspective of injectable treatment for T2D and identify characteristics of these treatments that are most important to patients. METHODS: Data were collected via an online survey study with a sample of individuals in the UK and US who were treated for T2D with injectable medication. The survey was designed to elicit perceptions of the treatment process for injectable glucagon-like peptide 1 (GLP-1) receptor agonists and insulin. RESULTS: The sample included 504 participants (251 UK, 253 US). Approximately half (50.4%) were treated with a GLP-1 receptor agonist and half (49.6%) were treated with insulin. Respondents were presented with a list of 17 characteristics of injectable medication and asked to indicate which were most important to them. Respondents most frequently selected confidence in administering the correct dose (n = 300, 59.5%); ease of selecting the correct dose (n = 268, 53.2%); overall ease of using the injection device (n = 239, 47.4%); frequency of injections (n = 223, 44.2%); and ease of carrying the device when necessary to inject away from home (n = 190, 37.7%). Characteristics least frequently cited as important included dose escalation (n = 79, 15.7%); handling the needle (n = 74, 14.7%); connectivity to an electronic device (n = 70, 13.9%); and the time required to prepare and inject each dose (n = 62, 12.3%). CONCLUSION: Results of this survey suggest that patients prioritize some attributes of injectable treatments over others. These findings may have implications for clinical practice and development of injection devices.

Effect of dulaglutide 3.0 and 4.5 mg on weight in patients with type 2 diabetes: Exploratory analyses of AWARD-11.

AIM: To evaluate the impact of dulaglutide 3.0 and 4.5 mg versus 1.5 mg on body weight in patients with type 2 diabetes (T2D) based on exploratory analyses of the AWARD-11 trial. MATERIALS AND METHODS: Patients were randomized to once-weekly dulaglutide 1.5 (n = 612), 3.0 (n = 616) or 4.5 mg (n = 614) for 52 weeks. The primary objective was superiority of dulaglutide 3.0 and/or 4.5 mg over 1.5 mg in HbA1c reduction at 36 weeks. Secondary and exploratory assessments included weight reduction in the overall trial population and baseline body mass index (BMI) and HbA1c subgroups. RESULTS: At baseline, patients had a mean age of 57.1 years, HbA1c 8.6% (70 mmol/mol), weight 95.7 kg and BMI 34.2 kg/m2 . At 36 weeks, dulaglutide 3.0 and 4.5 mg were superior to 1.5 mg for weight change from baseline (1.5 mg, -3.1 kg; 3.0 mg, -4.0 kg [P = .001]; 4.5 mg, -4.7 kg [P < .001]). Higher dulaglutide doses were associated with numerically greater weight reduction compared with 1.5 mg in each baseline BMI and HbA1c subgroup. Absolute weight reduction increased with increasing BMI category, but percentage weight loss was similar between subgroups. Weight reductions with dulaglutide were greater in patients with lower versus higher baseline HbA1c. CONCLUSIONS: In patients with T2D, inadequately controlled by metformin, incremental weight loss was observed with dulaglutide 1.5, 3.0 and 4.5 mg doses regardless of baseline BMI or HbA1c. Although absolute weight loss was numerically greater in patients with higher baseline BMI, percentage of weight loss was similar between BMI subgroups.

Efficacy and Safety of Dulaglutide 3.0 mg and 4.5 mg Versus Dulaglutide 1.5 mg in Metformin-Treated Patients With Type 2 Diabetes in a Randomized Controlled Trial (AWARD-11).

OBJECTIVE: To compare efficacy and safety of dulaglutide at doses of 3.0 and 4.5 mg versus 1.5 mg in patients with type 2 diabetes inadequately controlled with metformin. RESEARCH DESIGN AND METHODS: Patients were randomly assigned to once-weekly dulaglutide 1.5 mg, 3.0 mg, or 4.5 mg for 52 weeks. The primary objective was determining superiority of dulaglutide 3.0 mg and/or 4.5 mg over 1.5 mg in HbA1c reduction at 36 weeks. Secondary superiority objectives included change in body weight. Two estimands addressed efficacy objectives: treatment regimen (regardless of treatment discontinuation or rescue medication) and efficacy (on treatment without rescue medication) in all randomly assigned patients. RESULTS: Mean baseline HbA1c and BMI in randomly assigned patients (N = 1,842) was 8.6% (70 mmol/mol) and 34.2 kg/m2, respectively. At 36 weeks, dulaglutide 4.5 mg provided superior HbA1c reductions compared with 1.5 mg (treatment-regimen estimand: -1.77 vs. -1.54% [-19.4 vs. -16.8 mmol/mol], estimated treatment difference [ETD] -0.24% (-2.6 mmol/mol), P < 0.001; efficacy estimand: -1.87 vs. -1.53% [-20.4 vs. -16.7 mmol/mol], ETD -0.34% (-3.7 mmol/mol), P < 0.001). Dulaglutide 3.0 mg was superior to 1.5 mg for reducing HbA1c, using the efficacy estimand (ETD -0.17% [-1.9 mmol/mol]; P = 0.003) but not the treatment-regimen estimand (ETD -0.10% [-1.1 mmol/mol]; P = 0.096). Dulaglutide 4.5 mg was superior to 1.5 mg for weight loss at 36 weeks for both estimands (treatment regimen: -4.6 vs. -3.0 kg, ETD -1.6 kg, P < 0.001; efficacy: -4.7 vs. -3.1 kg, ETD -1.6 kg, P < 0.001). Common adverse events through 36 weeks included nausea (1.5 mg, 13.4%; 3 mg, 15.6%; 4.5 mg, 16.4%) and vomiting (1.5 mg, 5.6%; 3 mg, 8.3%; 4.5 mg, 9.3%). CONCLUSIONS: In patients with type 2 diabetes inadequately controlled by metformin, escalation from dulaglutide 1.5 mg to 3.0 mg or 4.5 mg provided clinically relevant, dose-related reductions in HbA1c and body weight with a similar safety profile.

The Relationship Between Timing of Initiation on a Glucagon-like Peptide-1 Receptor Agonist and Glycosylated Hemoglobin Values Among Patients With Type 2 Diabetes.

PURPOSE: This study examines the relationship between timing of initiation on a glucagon-like peptide-1 receptor agonist (GLP-1 RA) and glycosylated hemoglobin (HbA1c) values. METHODS: The IBM MarketScan databases were used to identify adults with type 2 diabetes mellitus (T2DM) who initiated GLP-1 RA therapy and had multiple recorded HbA1c results. Time to GLP-1 RA initiation was proxied by the number of classes of glucose-lowering agents prescribed in the 2 years before GLP-1 RA initiation, with fewer glucose-lowering agents indicating initiation of a GLP-1 RA earlier in disease progression. Paired t tests examined differences in HbA1c values from preperiod to 2-year postperiod. Multivariable analyses examined the relationship between time to GLP-1 RA initiation and postperiod HbA1c values. FINDINGS: Initiation on a GLP-1 RA was associated with a 0.6% reduction in HbA1c values over 2 years (P < 0.0001). Earliest starts were associated with a 1.3% reduction in HbA1c levels (P < 0.0001) and the highest likelihood of achieving a postperiod HbA1c level <7% (odds ratio, 4.9; 95% CI, 3.0-8.1). IMPLICATIONS: Results indicate that although initiation on a GLP-1 RA is generally associated with reduced HbA1c levels, there may be additional clinical benefits associated with earlier initiation of a GLP-1 RA.

Real-World Effectiveness of Dulaglutide in Patients with Type 2 Diabetes Mellitus: A Literature Review.

INTRODUCTION: Randomized controlled trials (RCTs) have demonstrated the efficacy of dulaglutide in adults with type 2 diabetes mellitus (T2DM), but results may not be generalizable in routine practice. This pragmatic literature review aimed to summarize real-world evidence (RWE) for dulaglutide. METHODS: The MEDLINE, EMBASE, NHS Economic Evaluation Database, and Health Technology Assessment databases were searched from January 2014 to July 2019 for studies providing RWE for dulaglutide in adults with T2DM regarding at least one outcome of interest (change in glycated hemoglobin [HbA1c]; weight; adherence; persistence; discontinuation; costs; healthcare resource utilization; health-related quality of life; patient satisfaction; and preference). Relevant congress abstracts were identified from EMBASE. RESULTS: A total of 29 studies (11 articles; 18 abstracts) were included. RWE for dulaglutide was not identified for all outcomes of interest. Dulaglutide reduced HbA1c from baseline to 3-24 months by 0.5-2.2% across studies (n = 20), and 23.4-55.7% of patients achieved HbA1c < 7.0%. Weight was reduced by 2.1-6.4 kg across studies of 3-12 months (n = 15). Based on outcomes from ten studies, 27.2-61.0% of dulaglutide patients were adherent. Mean persistence was 146-152 days and > 250 days in 6- and 12-month studies, respectively. Most studies reported discontinuation rates of 26.2-37.0%. Adherence and persistence were consistently reported to be greater in dulaglutide-treated patients in RW settings compared with other glucagon-like peptide-1 receptor agonists. Dulaglutide was associated with lower costs per 1% reduction in HbA1c compared with exenatide, liraglutide, or basal insulin (n = 3 studies). CONCLUSION: Evidence from RWE studies suggests that dulaglutide may be associated with clinically relevant reductions in HbA1c, with a favorable adherence, persistence, and discontinuation profile in patients with T2DM in routine clinical practice. These findings provide additional insights regarding the potential value of dulaglutide in real-world settings that may assist healthcare decision makers in the delivery of patient-centered care.

Shared Learnings on the New EMA First-in-Human and Early Clinical Trial Guideline: Proceedings From a DIAlogue Session at DIA Europe 2018.

The EU is a member of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH), and therefore adopts the ICH Guidelines, including the ICH M3 Guideline on Nonclinical Safety Studies. Following the 2016 incident in France with BIA 10-2474, and in light of the substantial evolvement of how early clinical development has been undertaken during the last 10 years, for example, conducting integrated (FIH) studies that include multiple parts (eg, single ascending doses, multiple ascending doses, food effect), EMA decided to update the existing 2007 FIH guideline. The key revisions to the 2007 guideline, now titled "Guideline on Strategies to Identify and Mitigate Risks for First-in-Human and Early Clinical Trials With Investigational Medicinal Products," include additional information. The revision reinforces the importance and impact of pharmacologic data, which supports the intended efficacy of the compound, risk assessment, and protocol design. The updates, effective February 2018, are intended to provide additional guidance and clarity for Sponsors developing FIH and early phase clinical research programs, and ultimately support subject safety. At the 2018 DIA Europe Annual Meeting in Basel, Switzerland, European regulators, industry representatives and academics convened a DIAlogue Session on April 17 to discuss how the revised 2017 guideline is being applied, and to establish recommendations for its application. Using two case studies as examples, the session participants discussed the nonclinical and clinical considerations for applying the newly revised recommendations, and interacted with a panel including regulators and industry representatives. The proceedings from this session reflect practical considerations for the implementation of the revised guideline.

Accelerating Pediatric Cancer Drug Development: Challenges and Opportunities for Pediatric Master Protocols.

Although outcomes for children with cancer have significantly improved over the past 40 years, there has been little progress in the treatment of some pediatric cancers, particularly when advanced. Additionally, clinical trial options and availability are often insufficient. Improved genomic and immunologic understanding of pediatric cancers, combined with innovative clinical trial designs, may provide an enhanced opportunity to study childhood cancers. Master protocols, which incorporate the use of precision medicine approaches, coupled with the ability to quickly assess the safety and effectiveness of new therapies, have the potential to accelerate early-phase clinical testing of novel therapeutics and which may result in more rapid approval of new drugs for children with cancer. Designing and conducting master protocols for children requires addressing similar principles and requirements as traditional adult oncology trials, but there are also unique considerations for master protocols conducted in children with cancer. The purpose of this paper is to define the key challenges and opportunities associated with this approach in order to ensure that master protocols can be adapted to benefit children and adolescents and ensure that adequate data are captured to advance, in parallel, the clinical development of investigational agents for children with cancer.

Enabling social listening for cardiac safety monitoring: Proceedings from a drug information association-cardiac safety research consortium cosponsored think tank.

This white paper provides a summary of the presentations and discussions from a think tank on "Enabling Social Listening for Cardiac Safety Monitoring" trials that was cosponsored by the Drug Information Association and the Cardiac Safety Research Consortium, and held at the White Oak headquarters of the US Food and Drug Administration on June 3, 2016. The meeting's goals were to explore current methods of collecting and evaluating social listening data and to consider their applicability to cardiac safety surveillance. Social listening is defined as the act of monitoring public postings on the Internet. It has several theoretical advantages for drug and device safety. First, these include the ability to detect adverse events that are "missed" by traditional sources and the ability to detect adverse events sooner than would be allowed by traditional sources, both by affording near-real-time access to data from culturally and geographically diverse sources. Social listening can also potentially introduce a novel patient voice into the conversation about drug safety, which could uniquely augment understanding of real-world medication use obtained from more traditional methodologies. Finally, it can allow for access to information about drug misuse and diversion. To date, the latter 2 of these have been realized. Although regulators from the Food and Drug Administration and the United Kingdom's Medicines and Healthcare Products Regulatory Agency participated in the think tank along with representatives from industry, academia, and patient groups, this article should not be construed to constitute regulatory guidance.

The role of DNA methylation in regulation of the murine Lhx3 gene.

LHX3 is a LIM-homeodomain transcription factor with critical roles in pituitary and nervous system development. Mutations in the LHX3 gene are associated with pediatric diseases featuring severe hormone deficiencies, hearing loss, developmental delay, and other symptoms. The mechanisms that govern LHX3/Lhx3 transcription are poorly understood. In this study, we examined the role of DNA methylation in the expression status of the mouse Lhx3 gene. Pituitary cells that do not normally express Lhx3 (Pit-1/0 cells) were treated with 5-aza-2'-deoxycytidine, a demethylating reagent. This treatment leads to activation of Lhx3 gene expression suggesting that methylation contributes to Lhx3 regulation. Treatment of Pit-1/0 pituitary cells with a combination of a demethylating reagent and a histone deacetylase inhibitor led to rapid activation of Lhx3 expression, suggesting possible crosstalk between DNA methylation and histone modification processes. To assess DNA methylation levels, treated and untreated Pit-1/0 genomic DNAs were subjected to bisulfite conversion and sequencing. Treated Pit-1/0 cells had decreased methylation at specific sites in the Lhx3 locus compared to untreated cells. Chromatin immunoprecipitation assays demonstrated interactions between the MeCp2 methyl binding protein and Lhx3 promoter regions in the Pit-1/0 cell line. Overall, this study demonstrates that DNA methylation patterns of the Lhx3 gene are associated with its expression status.

LHX3 interacts with inhibitor of histone acetyltransferase complex subunits LANP and TAF-1ß to modulate pituitary gene regulation.

LIM-homeodomain 3 (LHX3) is a transcription factor required for mammalian pituitary gland and nervous system development. Human patients and animal models with LHX3 gene mutations present with severe pediatric syndromes that feature hormone deficiencies and symptoms associated with nervous system dysfunction. The carboxyl terminus of the LHX3 protein is required for pituitary gene regulation, but the mechanism by which this domain operates is unknown. In order to better understand LHX3-dependent pituitary hormone gene transcription, we used biochemical and mass spectrometry approaches to identify and characterize proteins that interact with the LHX3 carboxyl terminus. This approach identified the LANP/pp32 and TAF-1ß/SET proteins, which are components of the inhibitor of histone acetyltransferase (INHAT) multi-subunit complex that serves as a multifunctional repressor to inhibit histone acetylation and modulate chromatin structure. The protein domains of LANP and TAF-1ß that interact with LHX3 were mapped using biochemical techniques. Chromatin immunoprecipitation experiments demonstrated that LANP and TAF-1ß are associated with LHX3 target genes in pituitary cells, and experimental alterations of LANP and TAF-1ß levels affected LHX3-mediated pituitary gene regulation. Together, these data suggest that transcriptional regulation of pituitary genes by LHX3 involves regulated interactions with the INHAT complex.

A recessive mutation resulting in a disabling amino acid substitution (T194R) in the LHX3 homeodomain causes combined pituitary hormone deficiency.

BACKGROUND/AIMS: Recessive mutations in the LHX3 homeodomain transcription factor gene are associated with developmental disorders affecting the pituitary and nervous system. We describe pediatric patients with combined pituitary hormone deficiency (CPHD) who harbor a novel mutation in LHX3. METHODS: Two female siblings from related parents were examined. Both patients had neonatal complications. The index patient had CPHD featuring deficiencies of GH, LH, FSH, PRL, and TSH, with later onset of ACTH deficiency. She also had a hypoplastic anterior pituitary, respiratory distress, hearing impairment, and limited neck rotation. The LHX3 gene was sequenced and the biochemical properties of the predicted altered proteins were characterized. RESULTS: A novel homozygous mutation predicted to change amino acid 194 from threonine to arginine (T194R) was detected in both patients. This amino acid is conserved in the DNA-binding homeodomain. Computer modeling predicted that the T194R change would alter the homeodomain structure. The T194R protein did not bind tested LHX3 DNA recognition sites and did not activate the α-glycoprotein and PRL target genes. CONCLUSION: The T194R mutation affects a critical residue in the LHX3 protein. This study extends our understanding of the phenotypic features, molecular mechanism, and developmental course associated with mutations in the LHX3 gene.

Model of pediatric pituitary hormone deficiency separates the endocrine and neural functions of the LHX3 transcription factor in vivo.

The etiology of most pediatric hormone deficiency diseases is poorly understood. Children with combined pituitary hormone deficiency (CPHD) have insufficient levels of multiple anterior pituitary hormones causing short stature, metabolic disease, pubertal failure, and often have associated nervous system symptoms. Mutations in developmental regulatory genes required for the specification of the hormone-secreting cell types of the pituitary gland underlie severe forms of CPHD. To better understand these diseases, we have created a unique mouse model of CPHD with a targeted knockin mutation (Lhx3 W227ter), which is a model for the human LHX3 W224ter disease. The LHX3 gene encodes a LIM-homeodomain transcription factor, which has essential roles in pituitary and nervous system development in mammals. The introduced premature termination codon results in deletion of the carboxyl terminal region of the LHX3 protein, which is critical for pituitary gene activation. Mice that lack all LHX3 function do not survive beyond birth. By contrast, the homozygous Lhx3 W227ter mice survive, but display marked dwarfism, thyroid disease, and female infertility. Importantly, the Lhx3 W227ter mice have no apparent nervous system deficits. The Lhx3 W227ter mouse model provides a unique array of hormone deficits and facilitates experimental approaches that are not feasible with human patients. These experiments demonstrate that the carboxyl terminus of the LHX3 transcription factor is not required for viability. More broadly, this study reveals that the in vivo actions of a transcription factor in different tissues are molecularly separable.

Maternal and postweaning diet interaction alters hypothalamic gene expression and modulates response to a high-fat diet in male offspring.

Epidemiological data and results from animal studies indicate that imbalances in maternal nutrition impact the expression of metabolic disorders in the offspring. We tested the hypothesis that consumption of excess saturated fats during pregnancy and lactation contributes to adult metabolic dysfunction and that these disturbances can be further influenced by the postweaning diet. Adult male offspring from chow-fed dams were compared with males from dams fed a diet high in saturated fat (45 kcal/100 kcal) before mating, pregnancy, and lactation. Offspring were weaned to a standard chow diet or high fat diet. Animals were killed at 120 days after a 24-h fast. Body weight, energy intake, fat deposition, serum leptin, and insulin were significantly higher in offspring from control or high-fat dams if fed a high-fat diet from weaning to adulthood. Only fat-fed offspring from fat-fed dams were hyperglycemic. Leptin receptor, proopiomelanocortin, and neuropeptide Y (NPY) were also significantly increased in offspring exposed to excess saturated fat during gestation and into adulthood, whereas NPY(1) receptor was downregulated. Signal transducer and activator of transcription 3 mRNA level was significantly higher in offspring from high-fat-fed dams compared with controls; however, no change was detected in cocaine and amphetamine-regulated transcript or suppressor of cytokine signaling 3. An increase in agouti-related protein expression did not reach significance. A significant reduction in phosphatidylinositol 3-kinase regulatory subunit (p85alpha) coupled to an upregulation of protein kinase B was observed in offspring from high-fat-fed dams transitioned to chow food, whereas p85alpha expression was significantly increased in high-fat offspring weaned to the high-fat diet. These data support the hypothesis that early life exposure to excess fat is associated with changes in hypothalamic regulation of body weight and energy homeostasis and that postweaning diet influences development of metabolic dysfunction and obesity.