Rickey R. Reinhardt

Update on the safety and efficacy of retroviral gene therapy for immunodeficiency due to adenosine deaminase deficiency

Adenosine deaminase (ADA) deficiency is a rare, autosomal-recessive systemic metabolic disease characterized by severe combined immunodeficiency (SCID). The treatment of choice for ADA-deficient SCID (ADA-SCID) is hematopoietic stem cell transplant from an HLA-matched sibling donor, although <25% of patients have such a donor available. Enzyme replacement therapy (ERT) partially and temporarily relieves immunodeficiency. We investigated the medium-term outcome of gene therapy (GT) in 18 patients with ADA-SCID for whom an HLA-identical family donor was not available; most were not responding well to ERT. Patients were treated with an autologous CD34(+)-enriched cell fraction that contained CD34(+) cells transduced with a retroviral vector encoding the human ADA complementary DNA sequence (GSK2696273) as part of single-arm, open-label studies or compassionate use programs. Overall survival was 100% over 2.3 to 13.4 years (median, 6.9 years). Gene-modified cells were stably present in multiple lineages throughout follow up. GT resulted in a sustained reduction in the severe infection rate from 1.17 events per person-year to 0.17 events per person-year (n = 17, patient 1 data not available). Immune reconstitution was demonstrated by normalization of T-cell subsets (CD3(+), CD4(+), and CD8(+)), evidence of thymopoiesis, and sustained T-cell proliferative capacity. B-cell function was evidenced by immunoglobulin production, decreased intravenous immunoglobulin use, and antibody response after vaccination. All 18 patients reported infections as adverse events; infections of respiratory and gastrointestinal tracts were reported most frequently. No events indicative of leukemic transformation were reported. Trial details were registered at www.clinicaltrials.gov as #NCT00598481.

Albiglutide does not impair the counter-regulatory hormone response to hypoglycaemia: a randomized, double-blind, placebo-controlled, stepped glucose clamp study in subjects with type 2 diabetes mellitus†

To determine if the glucagon‐like peptide‐1 (GLP‐1) receptor agonist albiglutide, once weekly, impairs counter‐regulatory responses during hypoglycaemia.

Effect of Renal Impairment on the Pharmacokinetics, Efficacy, and Safety of Albiglutide

Abstract Background: Chronic kidney disease is frequently present in patients with type 2 diabetes mellitus (T2DM). New therapeutic options in this patient subpopulation are needed. Objectives: Assess the effect of renal impairment on the pharmacokinetics (PK), efficacy, and safety of albiglutide in single- and multiple-dose studies. Methods: Pharmacokinetics, safety, and efficacy of once weekly albiglutide in patients with T2DM was assessed from a single-dose (30 mg), nonrandomized, open-label study (N = 41) including subjects with normal and varying degrees of renal impairment, including hemodialysis, and a pooled analysis of 4 phase 3, randomized, double-blind (1 open-label), active or placebo-controlled multiple-dose studies. The pooled analysis of the latter 4 studies (N = 1113) was part of the population PK analysis, which included subjects with normal and varying degrees of renal impairment (mild, moderate, severe) treated with albiglutide (30 to 50 mg) to primary end points of 26 to 52 weeks. Results: Single-dose PK showed area-under-the-curve ratios (and 90% CIs) of 1.32 (0.96–1.80), 1.39 (1.03–1.89), and 0.99 (0.63–1.57) for the moderate, severe, and hemodialysis groups, respectively, relative to the normal group. Results indicate that modest increases in plasma concentration of albiglutide were observed with the severity of renal impairment. There was a trend for more glycemic lowering as the estimated glomerular filtration rate decreased. The severe group had a higher frequency of gastrointestinal (eg, diarrhea, constipation, nausea, and vomiting) and hypoglycemic (with background sulfonylurea use) events compared with patients with mild or moderate renal impairment. Conclusion: The PK, efficacy, and safety data indicate that albiglutide has a favorable benefit/risk ratio in patients with T2DM and varying degrees of renal impairment, and the need for a dose adjustment is not suggested. Experience in patients with more severe renal impairment is very limited, so the recommendation is to use albiglutide carefully in this population. Clinical Trial Registration (ClinicalTrials.gov): NCT00938158, NCT00849017, NCT00838916, NCT00839527, NCT0198539.

Clinical Pharmacology of Albiglutide, a GLP-1 Receptor Agonist

Abstract Albiglutide is a glucagon-like peptide-1 analogue composed of tandem copies of modified human glucagon-like peptide-1 (7–36) coupled to recombinant human albumin that is approved in adults for the treatment of type 2 diabetes mellitus. After subcutaneous administration, albiglutide is likely primarily absorbed via the lymphatic circulation, with maximum concentrations being reached in 3 to 5 days; steady-state exposures are achieved following approximately 4 to 5 weeks of once-weekly administration. The elimination half-life of albiglutide is approximately 5 days. Clearance of albiglutide is 67 mL/h with between-subject variability of 34.9%; no covariates have been identified that would require dose adjustment of albiglutide. Albiglutide lowers the fasting plasma glucose and reduces postprandial glucose excursions. In addition, β-cell secretion is enhanced by albiglutide during hyperglycemia, whereas secretion is suppressed during hypoglycemia; α-cell response to hypoglycemia is not impaired by albiglutide. Albiglutide does not prolong the corrected QT interval but has a modest effect on heart rate in patients with type 2 diabetes mellitus. Dose adjustment is not suggested in patients with renal impairment, but experience in patients with severe renal impairment is very limited, and it is recommended that albiglutide be used with care in such patients due to an increased frequency of diarrhea, nausea, and vomiting. No clinically relevant drug interactions have been observed in clinical trials. Trial Registration: NCT00938158, NCT01406262, NCT00537719, NCT01077505, NCT01147731, NCT01147718, NCT01147692, NCT00354536, NCT00394030, NCT00530309, NCT01357889, NCT00518115, NCT01098461, NCT01475734, NCT00849017, NCT00838916, NCT00839527, NCT01098539.

Gastrointestinal safety across the albiglutide development programme

Gastrointestinal (GI) adverse events (AEs) are the most frequently reported treatment‐related AEs associated with glucagon‐like peptide‐1 receptor agonists (GLP‐1RAs) in the treatment of type 2 diabetes mellitus. The GI safety of albiglutide, a once‐weekly GLP‐1RA, was assessed using data from five phase III studies. In a pooled analysis of four placebo‐controlled trials, the most common GI AEs were diarrhoea (albiglutide, 14.5% vs. placebo, 11.5%) and nausea (albiglutide, 11.9% vs. placebo, 10.3%), with most patients experiencing 1–2 events. The majority were mild or moderate in intensity and their median duration was 3–4 days. Vomiting occurred in 4.9% of patients in the albiglutide vs. 2.6% in the placebo group. For both albiglutide and placebo, serious GI AEs (2.0% vs. 1.5%) and withdrawals attributable to GI AEs (1.7% vs. 1.5%) were low. In a 32‐week trial of albiglutide 50 mg weekly versus liraglutide 1.8 mg daily, nausea occurred in 9.9% of patients in the albiglutide group vs. 29.2% in the liraglutide group. Vomiting occurred in 5.0% in the albiglutide vs. 9.3% in the liraglutide group. In conclusion, albiglutide has an acceptable GI tolerability profile, with nausea and vomiting rates slightly higher than those for placebo but lower than those for liraglutide.

Gene Therapy for Adenosine Deaminase Deficiency: A Comprehensive Evaluation of Short- and Medium-Term Safety

Loss of adenosine deaminase activity leads to severe combined immunodeficiency (ADA-SCID); production and function of T, B, and natural killer (NK) cells are impaired. Gene therapy (GT) with an autologous CD34+-enriched cell fraction that contains CD34+ cells transduced with a retroviral vector encoding the human ADA cDNA sequence leads to immune reconstitution in most patients. Here, we report short- and medium-term safety analyses from 18 patients enrolled as part of single-arm, open-label studies or compassionate use programs. Survival was 100% with a median of 6.9 years follow-up (range, 2.3 to 13.4 years). Adverse events were mostly grade 1 or grade 2 and were reported by all 18 patients following GT. Thirty-nine serious adverse events (SAEs) were reported by 15 of 18 patients; no SAEs were considered related to GT. The most common adverse events reported post-GT include upper respiratory tract infection, gastroenteritis, rhinitis, bronchitis, oral candidiasis, cough, neutropenia, diarrhea, and pyrexia. Incidence rates for all of these events were highest during pre-treatment, treatment, and/or 3-month follow-up and then declined over medium-term follow-up. GT did not impact the incidence of neurologic/hearing impairments. No event indicative of leukemic transformation was reported.

Postprandial plasma glucose effects of once-weekly albiglutide for the treatment of type 2 diabetes.

ABSTRACT Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) vary in their structure, duration of action, efficacy, and safety. In order to optimize glycemic control, it is important to target both fasting (FPG) and postprandial plasma (PPG) glucose. Although phase 3 trials document the effect of GLP-1 RAs on glycated hemoglobin, few data are available to assess their effect on PPG. Albiglutide is a once-weekly GLP-1 RA with a half-life of ≈ 5 days. The goal of this review is to summarize the effects of albiglutide on PPG in four phase 2 trials and to describe the PPG-lowering effects of the GLP-1 RAs. At clinically relevant doses (30-64 mg), albiglutide consistently lowered PPG after each meal in addition to its effect on lowering FPG. Multiple weekly subcutaneous injections of albiglutide led to improvements in a variety of glycemic measures, including maximal reductions in PPG from baseline, postmeal glucose excursions, and FPG. Albiglutide, a longer-acting GLP-1 RAs, provides reductions in FPG, PPG following meals, and glucose over 24 hours.

Albiglutide efficacy and safety in the Latino/Hispanic subpopulation for the integrated phase III program

ABSTRACT Objective: to evaluate the efficacy and safety of albiglutide compared with placebo and active comparators from an integrated trial subpopulation of Latino/Hispanic patients whose type 2 diabetes mellitus (T2DM) was inadequately controlled on their current regimen of diet and exercise, with or without oral antidiabetic drugs (OADs) and/or insulin. Methods: Latino/Hispanic patient subpopulations (N = 1204) across 7 phase III albiglutide studies (N = 4400) were evaluated post-hoc for efficacy and safety. Comparators were placebo, sulfonylureas, insulin, thiazolidinediones, and dipeptidyl peptidase-4 inhibitors. Glycatedhemoglobin (HbA1c) change from baseline to the time of the primary endpoint assessment (from 26 to 104 weeks) was evaluated in patients on diet and exercise and/or OADs, with or without insulin. Patients were allowed to continue in the study if hyperglycemic rescue was required, according to a prespecified algorithm and at the discretion of the investigator. Results: At baseline in the Latino/Hispanic subpopulation, the mean HbA1c was 8.3%, mean age was 53 years, mean body mass index was 32 kg/m2, and mean duration of T2DM was 8.0 years. The primary endpoint of mean HbA1c difference (albiglutide – placebo) was −0.94% for the Latino/Hispanic subpopulation and −0.86% (p < 0.001) for the overall phase III population. Changes in fasting plasma glucose mirrored those of HbA1c. Weight loss with albiglutide was numerically greater than with OADs and insulin in both populations, but it was smaller than with liraglutide. Within the Latino/Hispanic subpopulation, more injection-site reactions were reported with albiglutide vs all comparators, while gastrointestinal and hypoglycemic adverse events were comparable between the two groups, and the latter was uncommon when used without insulin and/or a sulfonylurea. Conclusions: In the Latino/Hispanic population, albiglutide resulted in effective lowering of glucose and modest weight loss, and it was generally well tolerated.

Erratum to: Albiglutide Does Not Prolong QTc Interval in Healthy Subjects: A Thorough ECG Study

The online version of the original article can be found under doi:10.1007/s13300-014-0055-1.