Pharmacokinetics and Pharmacodynamics of Bimagrumab (BYM338).

BACKGROUND: Bimagrumab is a human monoclonal antibody binding to the activin type II receptor with therapeutic potential in conditions of muscle wasting and obesity. This phase I study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and safety of various dose regimens of bimagrumab and routes of administration in healthy older adults. METHODS: This was a randomized, double-blind, placebo-controlled, parallel-arm, multiple-dose study in older adult men and women (aged ≥ 70 years, body mass index [BMI] 18-34 kg/m2) with stable health and diet. The study comprised seven treatment groups (Cohorts 1-7). Participants received bimagrumab or placebo treatment every 4 weeks for three doses (Cohorts 1 [700 mg] and 2 [210 mg] intravenous infusion; Cohorts 3 [1500 mg] and 4 [525 mg] subcutaneous infusion), or every week for 12 doses (Cohorts 5 [300 mg], 6 [150 mg], and 7 [52.5 mg] subcutaneous bolus injection) and were followed up until week 20. Blood samples were collected for bimagrumab PK analysis. PD were assessed by dual energy X-ray absorptiometry to quantify the change from baseline in lean body mass (LBM) and fat body mass (FBM) compared with placebo. Safety was assessed throughout the study. RESULTS: Eighty-four of 91 (92.3%) randomized participants (mean age 74.5 years; BMI 28.0 kg/m2) completed the study. Demographic characteristics were generally balanced across the groups. A target-mediated drug disposition profile was observed following both intravenous and subcutaneous administration. The absolute subcutaneous bioavailability was estimated at approximately 40%. LBM increased by 4-6% (1.5-2 kg) from baseline throughout the treatment period for intravenous and subcutaneous regimens, except for the 52.5 mg subcutaneous dose, which did not differ from placebo. Concurrently, there was a decrease in FBM (approximately 2-3 kg) for all intravenous and subcutaneous regimens. Bimagrumab was generally safe and well tolerated; adverse events were mostly mild to moderate in severity. CONCLUSIONS: Dose levels of bimagrumab administered weekly subcutaneously resulted in PK profiles and PD effects comparable with monthly intravenous dosing, which supports the feasibility of the subcutaneous route of administration for bimagrumab for future clinical development.

Comorbidity of inflammatory bowel disease in children and adolescents with type 1 diabetes.

AIM: To determine the prevalence of inflammatory bowel disease (IBD) in patients with type 1 diabetes (T1D) and to characterise patients with both diseases. METHODS: Data of 65.147 patients with T1D ≤18 years of 379 centres in Germany and Austria participating in the DPV initiative were analysed. A total of 63 children had comorbid IBD; IBD prevalence was 0.1%. Regression models were used to analyse differences in metabolic control, acute complications and steroid intake. RESULTS: Mean BMI-SDS in patients with T1D and IBD was lower (-0.15 ± 0.11) compared to patients with T1D only (0.27 ± 0.00, p < .001). Patients with T1D and IBD had a significantly higher use of steroids (22% ± 0.05% vs. 1% ± 0.00, p < .001) and a significantly higher rate of severe hypoglycaemic events per patient year (0.33 ± 0.07 vs. 0.16 ± 0.00, p = .001). No differences were found in HbA1c levels, insulin dose and occurrence of DKA. CONCLUSION: Although children and adolescents with T1D and IBD take steroids more often, they suffer from severe hypoglycaemia more frequently and have a lower BMI-SDS. These findings might be explained by chronic intestinal inflammation leading to malabsorption, malnutrition and increased severe hypoglycaemia.

Detection of CSF1 rearrangements deleting the 3' UTR in tenosynovial giant cell tumors.

Tenosynovial giant cell tumors (TGCTs) are characterized by rearrangements of CSF1, thought to drive overexpression of macrophage colony-stimulating factor (CSF1), thereby promoting tumor growth and recruitment of non-neoplastic mononuclear and multinucleated inflammatory cells. While fusions to collagen promoters have been described, the mechanism of CSF1 overexpression has been unclear in a majority of cases. Two cohorts of TGCT were investigated for CSF1 rearrangements using fluorescence in situ hybridization (FISH) and either RNA-seq or DNA-seq with Sanger validation. The study comprised 39 patients, including 13 localized TGCT, 21 diffuse TGCT, and five of unspecified type. CSF1 rearrangements were identified by FISH in 30 cases: 13 translocations, 17 3' deletions. Sequencing confirmed CSF1 breakpoints in 28 cases; in all 28 the breakpoint was found to be downstream of exon 5, replacing or deleting a long 3' UTR containing known miRNA and AU-rich element negative regulatory sequences. We also confirmed the presence of CBL exon 8-9 mutations in six of 21 cases. In conclusion, TGCT in our large cohort were characterized by variable alterations, all of which led to truncation of the 3' end of CSF1, instead of the COL6A3-CSF1 fusions previously reported in some TGCTs. The diversity of fusion partners but consistent integrity of CSF1 functional domains encoded by exons 1-5 support a hypothesis that CSF1 overexpression results from transcription of a truncated form of CSF1 lacking 3' negative regulatory sequences. The presence of CBL mutations affecting the linker and RING finger domain suggests an alternative mechanism for increased CSF1/CSF1R signaling in some cases.

Colony-Stimulating Factor-1 Antibody Lacnotuzumab in a Phase 1 Healthy Volunteer Study and Mechanistic Investigation of Safety Outcomes.

The colony-stimulating factor-1 (CSF-1) receptor pathway has been implicated in a variety of diseases, and CSF-1-dependent mechanisms are also involved in bloodborne protein clearance. Lacnotuzumab is a novel, high-affinity, humanized, anti-CSF-1 monoclonal antibody that prevents CSF-1-mediated receptor activation. This phase 1, two-part, double-blind study in healthy volunteers assessed the safety and tolerability of lacnotuzumab and its pharmacokinetics (PK) and pharmacodynamic properties. Part A (n = 36) was a single, ascending-dose assessment of eight lacnotuzumab doses (0.01-20 mg/kg); in part B (n = 16), lacnotuzumab was administered at either 5 or 10 mg/kg. In each study cohort, individuals were randomized 3:1 to lacnotuzumab or placebo. Lacnotuzumab was generally well tolerated. At higher doses (10 and 20 mg/kg), creatine kinase (CK) elevations (>5× the upper limit of normal, but asymptomatic and reversible) and mild transient periorbital swelling were reported. Most adverse events (AEs) were low-grade, no unexpected or novel AEs were observed, and there were no discontinuations for AEs. Free, unbound lacnotuzumab serum concentration-time profiles showed nonlinear PK across doses from 0.01 to 20 mg/kg, with faster apparent elimination at lower doses or concentrations; this finding was consistent with apparent target-mediated drug disposition. Lacnotuzumab also showed dose-dependent, on-target effects on multiple downstream biomarkers. Preclinical investigations of the CK elevation and periorbital swelling observed after lacnotuzumab administration suggest that these are reversible, nonpathological events linked to inhibition of the CSF-1 pathway. These data support further evaluation of lacnotuzumab in clinical studies.

Screening for Type 1 Diabetes Risk in Newborns: The Freder1k Pilot Study in Saxony.

An increased risk for type 1 diabetes can be identified using genetic and immune markers. The Freder1k study introduces genetic testing for type 1 diabetes risk within the context of the newborn screening in order to identify newborns with a high risk to develop type 1 diabetes for follow-up testing of early stage type 1 diabetes and for primary prevention trials. Consent for research-based genetic testing of type 1 diabetes risk is obtained with newborn screening. Increased risk is assessed using three single nucleotide polymorphisms for HLA DRB1*03 (DR3), HLA DRB1*04 (DR4), HLA DQB1*0302 (DQ8) alleles, and defined as 1. an HLA DR3/DR4-DQ8 or DR4-DQ8/DR4-DQ8 genotype or 2. an HLA DR4-DQ8 haplotype and a first-degree family history of type 1 diabetes. Families of infants with increased risk are asked to participate in follow-up visits at infant age 6 months, 2 years, and 4 years for autoantibody testing and early diagnosis of type 1 diabetes. After 8 months, the screening rate has reached 181 per week, with 63% coverage of newborns within Freder1k-clinics and 24% of all registered births in Saxony. Of 4178 screened, 2.6% were identified to have an increased risk, and around 80% of eligible infants were recruited to follow-up. Psychological assessment of eligible families is ongoing with none of 31 families demonstrating signs of excessive burden associated with knowledge of type 1 diabetes risk. This pilot study has shown that it is feasible to perform genetic risk testing for childhood disease within the context of newborn screening programs.

¹8F-fluoride PET as a noninvasive imaging biomarker for determining treatment efficacy of bone active agents at the hip: a prospective, randomized, controlled clinical study.

The functional imaging technique of ¹8F-fluoride positron emission tomography (¹8F-PET) allows the noninvasive quantitative assessment of regional bone formation at any skeletal site, including the spine and hip. The aim of this study was to determine if ¹8F-PET can be used as an early biomarker of treatment efficacy at the hip. Twenty-seven treatment-naive postmenopausal women with osteopenia were randomized to receive teriparatide and calcium and vitamin D (TPT group, n = 13) or calcium and vitamin D only (control group, n = 14). Subjects in the TPT group were treated with 20 µg/day teriparatide for 12 weeks. ¹8F-PET scans of the proximal femur, pelvis, and lumbar spine were performed at baseline and 12 weeks. The plasma clearance of ¹8F-fluoride to bone, K(i), a validated measurement of bone formation, was measured at four regions of the hip, lumbar spine, and pelvis. A significant increase in K(i) was observed at all regions of interest (ROIs), including the total hip (+27%, p = 0.002), femoral neck (+25%, p = 0.040), hip trabecular ROI (+21%, p = 0.017), and hip cortical ROI (+51%, p = 0.001) in the TPT group. Significant increases in K(i) in response to TPT were also observed at the lumbar spine (+18%, p = 0.001) and pelvis (+42%, p = 0.001). No significant changes in K(i) were observed for the control group. Changes in BMD and bone turnover markers were consistent with previous trials of teriparatide. In conclusion, this is the first study to our knowledge to demonstrate that ¹8F-PET can be used as an imaging biomarker for determining treatment efficacy at the hip as early as 12 weeks after initiation of therapy.