Letter: Severe underweight and sarcopenia in decompensated cirrhosis are associated with high FGF21 levels-authors' reply

This article is linked to Alkhouri et al papers. To view these articles, visit https://doi.org/10.1111/apt.17709 and https://doi.org/10.1111/apt.17881

Population Pharmacokinetics and Pharmacodynamics of Pegozafermin in Patients with Nonalcoholic Steatohepatitis

Pegozafermin is a long-acting glycoPEGylated analog of fibroblast growth factor 21 (FGF21) in development for the treatment of nonalcoholic steatohepatitis (NASH) and severe hypertriglyceridemia. In a phase Ib/IIa placebo-controlled, double-blind, multiple ascending dose study in patients with NASH (NCT04048135), administration of pegozafermin resulted in clinically meaningful reductions in hepatic fat fraction (HFF), with a favorable safety and tolerability profile. We aimed to characterize the relationship between pegozafermin dosing, exposure and effects on HFF reduction. We used pharmacokinetic (PK) and pharmacodynamic (PD) modeling of data from the phase Ib/IIa study to identify model parameters and covariates affecting the exposure-response relationship. Clinical simulations were performed to help support dose selection for larger studies. Pegozafermin exposure was adequately described by a one compartment PK model, with one additional transit absorption compartment. PK/PD modeling demonstrated that HFF reduction was significantly related to pegozafermin exposure. HFF outcomes were correlated with average pegozafermin concentrations regardless of weekly dosing (q.w.) or dosing every 2 weeks (q2w). The significant PK/PD model covariates included baseline body weight, alanine aminotransferase level, and liver volume. Simulations showed that the 30 mg q.w. dose approximated the full PD effect; almost all patients would benefit from a greater than or equal to 30% HFF reduction, suggesting fibrosis regression. Furthermore, 44 mg q2w dosing (~22 mg q.w.) appeared to be an effective regimen for HFF reduction. Our modeling supports the feasibility of q.w. and q2w dosing for achieving favorable treatment outcomes in patients with NASH, and provides the rationale for dose selection for the phase IIb ENLIVEN study (NCT04929483).

Clinical trial: Effects of pegozafermin on the liver and on metabolic comorbidities in subjects with biopsy-confirmed nonalcoholic steatohepatitis

BACKGROUND

An approved therapy for nonalcoholic steatohepatitis (NASH) and fibrosis remains a major unmet medical need.

AIM

To investigate the histological and metabolic benefits of pegozafermin, a glycoPEGylated FGF21 analogue, in subjects with biopsy-confirmed NASH.

METHODS

This proof-of-concept, open-label, single-cohort study, part 2 of a phase 1b/2a clinical trial, was conducted at 16 centres in the United States. Adults (age 21-75 years) with NASH (stage 2 or 3 fibrosis, NAS≥4) and magnetic resonance imaging proton density fat fraction (MRI-PDFF) ≥8% received subcutaneous pegozafermin 27 mg once weekly for 20 weeks. Primary outcomes were improvements in liver histology, and safety and tolerability.

RESULTS

Of 20 enrolled subjects, 19 completed the study. Twelve subjects (63%) met the primary endpoint of ≥2-point improvement in NAFLD activity score with ≥1-point improvement in ballooning or lobular inflammation and no worsening of fibrosis. Improvement of fibrosis without worsening of NASH was observed in 26% of subjects, and NASH resolution without worsening of fibrosis in 32%. Least-squares mean relative change from baseline in MRI-PDFF was -64.7% (95% CI: -71.7, -57.7; p < 0.0001). Significant improvements from baseline were also seen in serum aminotransferases, noninvasive fibrosis tests, serum lipids, glycaemic control and body weight. Adverse events (AEs) were reported in 18 subjects (90%). The most frequently reported AEs were mild/moderate nausea and diarrhoea. There were no serious AEs, discontinuations due to AEs, or deaths.

CONCLUSIONS

Pegozafermin treatment for 20 weeks had beneficial effects on hepatic and metabolic parameters and was well tolerated in subjects with NASH.

CLINICALTRIALS

gov: NCT04048135.

Systems Biology and Peptide Engineering to Overcome Absorption Barriers for Oral Peptide Delivery: Dosage Form Optimization Case Study Preceding Clinical Translation

Oral delivery of peptides and biological molecules promises significant benefits to patients as an alternative to daily injections, but the development of these formulations is challenging due to their low bioavailability and high pharmacokinetic variability. Our earlier work focused on the discovery of MEDI7219, a stabilized, lipidated, glucagon-like peptide 1 agonist peptide, and the selection of sodium chenodeoxycholate (Na CDC) and propyl gallate (PG) as permeation enhancer combinations. We hereby describe the development of the MEDI7219 tablet formulations and composition optimization via in vivo studies in dogs. We designed the MEDI7219 immediate-release tablets with the permeation enhancers Na CDC and PG. Immediate-release tablets were coated with an enteric coating that dissolves at pH ≥ 5.5 to target the upper duodenal region of the gastrointestinal tract and sustained-release tablets with a Carbopol bioadhesive polymer were coated with an enteric coating that dissolves at pH ≥ 7.0 to provide a longer presence at the absorption site in the gastrointestinal tract. In addition to immediate- and enteric-coated formulations, we also tested a proprietary delayed release erodible barrier layer tablet (OralogiKTM) to deliver the payload to the target site in the gastrointestinal tract. The design of tablet dosage forms based on the optimization of formulations resulted in up to 10.1% absolute oral bioavailability in dogs with variability as low as 26% for MEDI7219, paving the way for its clinical development.

Development of an orally delivered GLP-1 receptor agonist through peptide engineering and drug delivery to treat chronic disease

Peptide therapeutics are increasingly used in the treatment of disease, but their administration by injection reduces patient compliance and convenience, especially for chronic diseases. Thus, oral administration of a peptide therapeutic represents a significant advance in medicine, but is challenged by gastrointestinal instability and ineffective uptake into the circulation. Here, we have used glucagon-like peptide-1 (GLP-1) as a model peptide therapeutic for treating obesity-linked type 2 diabetes, a common chronic disease. We describe a comprehensive multidisciplinary approach leading to the development of MEDI7219, a GLP-1 receptor agonist (GLP-1RA) specifically engineered for oral delivery. Sites of protease/peptidase vulnerabilities in GLP-1 were removed by amino acid substitution and the peptide backbone was bis-lipidated to promote MEDI7219 reversible plasma protein binding without affecting potency. A combination of sodium chenodeoxycholate and propyl gallate was used to enhance bioavailability of MEDI7219 at the site of maximal gastrointestinal absorption, targeted by enteric-coated tablets. This synergistic approach resulted in MEDI7219 bioavailability of ~ 6% in dogs receiving oral tablets. In a dog model of obesity and insulin resistance, MEDI7219 oral tablets significantly decreased food intake, body weight and glucose excursions, validating the approach. This novel approach to the development of MEDI7219 provides a template for the development of other oral peptide therapeutics.

First-in-Human, Phase 1 Dose-Escalation Study of Biparatopic Anti-HER2 Antibody-Drug Conjugate MEDI4276 in Patients with HER2-positive Advanced Breast or Gastric Cancer

MEDI4276 is a biparatopic tetravalent antibody targeting two nonoverlapping epitopes in subdomains 2 and 4 of the HER2 ecto-domain, with site-specific conjugation to a tubulysin-based microtubule inhibitor payload. MEDI4276 demonstrates enhanced cellular internalization and cytolysis of HER2-positive tumor cells in vitro This was a first-in-human, dose-escalation clinical trial in patients with HER2-positive advanced or metastatic breast cancer or gastric cancer. MEDI4276 doses escalated from 0.05 to 0.9 mg/kg (60- to 90-minute intravenous infusion every 3 weeks). Primary endpoints were safety and tolerability; secondary endpoints included antitumor activity (objective response, progression-free survival, and overall survival), pharmacokinetics, and immunogenicity. Forty-seven patients (median age 59 years; median of seven prior treatment regimens) were treated. The maximum tolerated dose was exceeded at 0.9 mg/kg with two patients experiencing dose-limiting toxicities (DLTs) of grade 3 liver function test (LFT) increases, one of whom also had grade 3 diarrhea, which resolved. Two additional patients reported DLTs of grade 3 LFT increases at lower doses (0.4 and 0.6 mg/kg). The most common (all grade) drug-related adverse events (AEs) were nausea (59.6%), fatigue (44.7%), aspartate aminotransferase (AST) increased (42.6%), and vomiting (38.3%). The most common grade 3/4 drug-related AE was AST increased (21.3%). Five patients had drug-related AEs leading to treatment discontinuation. In the as-treated population, there was one complete response (0.5 mg/kg; breast cancer), and two partial responses (0.6 and 0.75 mg/kg; breast cancer)-all had prior trastuzumab, pertuzumab, and ado-trastuzumab emtansine (T-DM1). MEDI4276 has demonstrable clinical activity but displays intolerable toxicity at doses >0.3 mg/kg.

Results from an international phase 2 study of the anti-CD22 immunotoxin moxetumomab pasudotox in relapsed or refractory childhood B-lineage acute lymphoblastic leukemia

BACKGROUND

In a multicenter phase 1 study of children with relapsed/refractory acute lymphoblastic leukemia (ALL), moxetumomab pasudotox, an anti-CD22 immunotoxin, demonstrated a manageable safety profile and preliminary evidence of clinical activity. A phase 2 study further evaluated efficacy.

PROCEDURE

This international, multicenter, phase 2 study enrolled children with relapsed/refractory B-cell precursor ALL who received moxetumomab pasudotox 40 µg/kg intravenously every other day, for six doses per 21-day cycle. The primary objective was to evaluate the complete response (CR) rate. Secondary objectives included safety, pharmacokinetics, and immunogenicity evaluations.

RESULTS

Thirty-two patients (median age, 10 years) were enrolled at 16 sites; 30 received study drug and were evaluable for safety; 28 were evaluable for response. The objective response rate was 28.6%, with three patients (10.7%) achieving morphologic CR, and five patients (17.9%) achieving partial response. Disease progression occurred in 11 patients (39.3%). Ten patients (33.3%) experienced at least one treatment-related serious adverse event, including capillary leak syndrome (CLS; n = 6), hemolytic uremic syndrome (HUS; n = 4), and treatment-related death (n = 1) from pulmonary edema. No differences were observed in inflammatory markers in patients who did or did not develop CLS or HUS.

CONCLUSIONS

Despite a signal for clinical activity, this phase 2 study was terminated at interim analysis for a CR rate that did not reach the stage 1 target. Preclinical data suggest enhanced efficacy of moxetumomab pasudotox via continuous infusion or in combination regimens; thus, further studies designed to optimize the efficacy and safety of moxetumomab pasudotox in pediatric ALL may be warranted.

Population pharmacokinetics, efficacy, and safety of moxetumomab pasudotox in patients with relapsed or refractory hairy cell leukaemia

AIMS

To characterize the pharmacokinetics (PK) of moxetumomab pasudotox, an anti-CD22 recombinant immunotoxin, in adults with relapsed or refractory hairy cell leukaemia, we examined data from a phase 1 study (Study 1001; n = 49) and from the pivotal clinical study (Study 1053; n = 74).

METHODS

Data from both studies were pooled (n = 123) to develop a population PK model. Covariates included demographics, disease state, liver and kidney function, prior treatment, and antidrug antibodies (ADAs). Exposure-response and exposure-safety were analysed separately by study. A 1-compartment model with linear elimination from the central compartment and 2 clearance (CL) rates was developed.

RESULTS

Moxetumomab pasudotox was cleared more rapidly after cycle 1, day 1 (CL₁ = 24.7 L/h) than subsequently (CL₂ = 3.76 L/h), with high interindividual variability (116 and 109%, respectively). In Study 1053, patients with ADA titres >10 240 showed ~4-fold increase in CL. Higher exposures (≥median) were related to higher response rates, capillary leak syndrome and increased creatinine (Study 1053 only), or grade ≥3 adverse events (Study 1001 only). Clinical benefits were still observed in patients with lower exposure or high ADA titres.

CONCLUSION

Despite a high incidence of immunogenicity with increased clearance, moxetumomab pasudotox demonstrated efficacy in hairy cell leukaemia.

MEDI3726, a prostate-specific membrane antigen (PSMA)-targeted antibody-drug conjugate (ADC) in mCRPC after failure of abiraterone or enzalutamide

99

Background: MEDI3726 is an ADC targeting PSMA. Once bound to PSMA and internalized, the released pyrrolobenzodiazepine dimer toxin crosslinks DNA and triggers cell death. This phase 1 study evaluated the safety and efficacy of MEDI3726 in mCRPC after failure of abiraterone and/or enzalutamide and a taxane-based therapy. Methods: The starting dose was 0.015 mg/kg MEDI3726 IV Q3W until disease progression or unacceptable toxicity. Dose escalation used a modified toxicity probability interval algorithm (mTPI). The primary objectives were safety, adverse events (AEs) and dose-limiting toxicities (DLTs) and to determine the maximum tolerated (MTD) or administered (MAD) dose. Secondary objectives included antitumor activity, pharmacokinetics and immunogenicity. The endpoint for activity was composite response: confirmed response by RECIST v1.1, and/or PSA decrease of ≥ 50% after ≥ 12 wks, and/or confirmed conversion in circulating tumor cell count, defined as a decrease from ≥ 5 to < 5 cells/7.5 mL. Efficacy analyses were based on Prostate Working Group Criteria. Mutational profiles were evaluated in ctDNA. Results: As of Sept 27 2019, 33 pts received MEDI3726. Median age was 71.0 yr. Median number of prior regimens was 4. Median follow-up was 5.4 mo. Drug-related AEs occurred in 30 (90.9%), being grade 3/4 in 15 (45.5%), serious in 11 (33.3%) and causing discontinuation in 13 (39.4%). There were no drug-related deaths. One pt at 0.3 mg/kg had a DLT of Grade 3 thrombocytopenia. No MTD was identified per mTPI; the MAD was 0.3 mg/kg. MEDI3726 had nonlinear PK with a short t1/2 (0.3–2 d). Three pts (15.8%) at baseline and 6 (33.3%) post-baseline had antidrug antibodies, with no correlation to PK exposure. Composite response rate across all doses was 2/33 (6.1%). Time to response was 0.3 mo; duration of response was 1.8–3.8 mo. Median progression-free survival was 3.9 mo and median overall survival was 10.6 mo. Conclusions: An MTD was not identified, but drug-related AEs (skin toxicities and effusions) prevented raising the dose over 0.3 mg/kg and limited the number of cycles. Responses were seen at higher doses, but were not durable as pts discontinued due to drug-related AEs. Clinical trial information: NCT02991911.