ABSTRACT
This first‐in‐human study investigated the safety, pharmacokinetics, and pharmacodynamics of the long‐acting fibroblast growth factor 21 (FGF21) analog zalfermin. Healthy male participants (n = 56) with body mass index 25.0–34.9 kg/m2 were randomized to single ascending doses (2, 6, 12, 24, 48, 96, and 180 mg) of subcutaneous zalfermin or placebo. In a second study, a single dose of 12, 30, or 96 mg was administered to Japanese (n = 24) and non‐Asian (n = 18) healthy males to confirm a consistent safety and pharmacokinetic profile across ethnicity. Overall, 98 participants were enrolled across both studies and followed for 36 days. Blood samples were obtained for safety and for pharmacokinetic and pharmacodynamic assessments. The primary endpoint for both studies was the number of adverse events from treatment initiation to the end of follow‐up, which was greater in the highest zalfermin dose cohorts in both studies. Adverse events were non‐serious, mainly gastrointestinal‐related, and mostly mild to moderate in severity; no deaths occurred. In both studies, dose proportionality was established for maximum serum concentration and area under the curve from time 0 to infinity. Time to maximum serum concentration ranged from 24 to 54 h. The serum half‐life of zalfermin was ~120 h in both studies, compatible with once‐weekly dosing. Significant improvements in plasma lipids were observed. Zalfermin had an acceptable safety profile across all single ascending doses, consistent with the FGF21 class. Further investigations into multiple ascending doses of zalfermin and treatment duration are warranted to assess the potential treatment of steatohepatitis and cardiometabolic disease.
Trial Registration: ClinicalTrials.gov (NCT03015207 and NCT04722653)
Keywords: adverse drug reactions, adverse events, ethnicity, liver, metabolism, obesity, pharmacodynamics, pharmacokinetics, pharmacology, phase I
Study Highlights.
- What is the current knowledge on the topic?
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○There are few pharmacotherapy options available for the treatment of metabolic dysfunction‐associated steatohepatitis (MASH).
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○Fibroblast growth factor 21 (FGF21) is a metabolic regulator that has been associated with improvements in plasma insulin, liver fat, body weight, and lipid levels.
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○This has led to the pursuit of FGF21 analogs as a pharmacotherapy for the treatment of obesity, type 2 diabetes, dyslipidemia, and MASH. The potential benefits of FGF21 as an effective pharmacotherapy have been evaluated in several clinical trials to date.
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- What question did this study address?
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○What is the safety and tolerability of zalfermin in otherwise healthy humans and what are its pharmacokinetic and pharmacodynamic properties?
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○In what ways do the effects and pharmacokinetics of zalfermin compare with, or differ from, previous FGF21 analogs?
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- What does this study add to our knowledge?
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○With the acceptable safety profile of zalfermin established in healthy participants and its half‐life determined as approximately 120 h, further clinical development of zalfermin can be safely investigated at multiple ascending dose levels.
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- How might this change clinical pharmacology or translational science?
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○Zalfermin has potential as an alternative option for the treatment of a range of cardiometabolic diseases via a possible once‐weekly dosing regimen.
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1. Introduction
Obesity is a global pandemic that has contributed to the increased prevalence of many cardiometabolic diseases such as severe hypertriglyceridemia, type 2 diabetes (T2D), and metabolic dysfunction‐associated steatotic liver disease (MASLD) [1, 2]. MASLD is a chronic liver disease that is increasing in prevalence worldwide [3]. It is estimated that 20%–30% of patients with MASLD progress to metabolic dysfunction‐associated steatohepatitis (MASH) [4], a chronic disorder characterized by hepatocellular injury in the form of steatosis, hepatocyte ballooning, inflammation, and fibrosis. MASH can further lead to cirrhosis, hepatocellular carcinoma, and death [3, 5]. The prevalence of advanced liver fibrosis and cirrhosis in the general population worldwide is approximately 3.3% and 1.3%, respectively [6]. Currently, there is only one pharmacotherapy conditionally approved by the Food and Drug Administration (FDA) for patients with MASH with fibrosis stage F2 or F3, who often have other cardiometabolic‐related comorbidities [7, 8]. Thus, there is an unmet need for effective treatment options that can target fibrosis and the late cirrhotic stage of MASH.
Fibroblast growth factor 21 (FGF21) is a 181‐amino acid protein, secreted primarily from the liver, that acts as a pleiotropic metabolic regulator of glucose, lipids, and amino‐acid metabolism. In preclinical studies, activation of the FGF21 receptor complex was associated with several beneficial effects including normalization of blood glucose, lowering of plasma insulin, liver fat, and body weight and improving lipid levels [9, 10, 11, 12]. This has led to the pursuit of FGF21 as a pharmacotherapy for the treatment of metabolic syndrome including obesity, T2D, dyslipidemia, and MASH, with preclinical data confirmed in several clinical trials [13, 14, 15, 16].
The novel FGF21 analog zalfermin (formerly NNC0194‐0499) is a potent FGF21‐receptor agonist that is modified in position 180 with C18 fatty diacid alkylation, making it strongly albumin bound and preventing proteolytic cleavage of the C‐terminal [10]. Preclinical tests of zalfermin's pharmacokinetic (PK) and pharmacodynamic (PD) properties in cellular systems and animal models revealed it to have a receptor selectivity that resembles native FGF21 (e.g., naturally occurring) and a half‐life in cynomolgus monkeys of 53 h, and it effectively induced pharmacologically mediated body weight loss in obese mice [10].
This is the first in‐human assessment of zalfermin to evaluate the safe dose range and investigate any potential side effects. As zalfermin is under development for the potential treatment of MASH and other cardiometabolic comorbidities, the PD effects of zalfermin were assessed with body weight and lipid profile analyses.
Herein, we report the safety profile and tolerability, PK, and PD of zalfermin administered via a single ascending subcutaneous (s.c.) dose in healthy male participants with overweight or obesity (study 1). We also conducted a separate study involving healthy Japanese and non‐Asian male participants to evaluate the safety profile and PK characteristics of zalfermin across ethnicity (study 2).
2. Materials and Methods
2.1. Study Design and Participants
2.1.1. Study 1—Healthy Male Participants
Study 1 (NCT03015207) was a double‐blinded, placebo‐controlled, randomized, Phase I, single ascending dose, first‐in‐human study that enrolled male participants with overweight or obesity and who were otherwise healthy. Participants were aged between 22 and 55 years with a body mass index (BMI) of 25.0–34.9 kg/m2 and were excluded if they had concomitant illness or were receiving concomitant medication at baseline. Participants were randomized 3:1 to receive either a single dose of s.c. zalfermin 15 mg/mL (in ascending order: 2, 6, 12, 24, 48, 96, or 180 mg) or placebo (Figure S1), administered into the abdomen in the morning. The maximum injection volume for the 180 mg dose was 12 mL, consisting of eight injections of 1.5 mL. Two in‐house site visits were included: one of 7 days and a 3‐day follow‐up visit. Five ambulatory visits were included (visits 3–7) and the total duration of the study per participant was approximately 36 days.
2.1.2. Study 2—Healthy Japanese and Non‐Asian Male Participants
Study 2 (NCT04722653) included Japanese and non‐Asian male participants with overweight or obesity and who were otherwise healthy. Participants in the Japanese cohort were randomized 3:1 to receive either a single dose of s.c. zalfermin 50 mg/mL (in ascending order: 12, 30, or 96 mg) or placebo, administered into the abdomen in the morning. The maximum injection volume for the 96 mg dose was 1.92 mL (two injections of 0.96 mL). The non‐Asian participants were non‐randomized and received a single s.c. dose of zalfermin at each dose level (12, 30, and 96 mg); no placebo was administered to the non‐Asian participants. Further details of the study design and participants for study 2 are described in the Supporting Information Appendix.
2.2. Ethics Statement
Both studies were conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. The protocols for each study were approved by an independent ethics committee/institutional review board and all participants provided written informed consent. Study 1 was approved by the United States FDA and study 2 by the Pharmaceutical and Medical Devices Agency in Japan.
2.3. Safety Outcomes and Assessments
The primary endpoint for both studies was the number of treatment‐emergent adverse events (TEAEs) recorded from the time of zalfermin administration (day 1) until the end of the follow‐up period (day 36), coded using the Medical Dictionary for Regulatory Activities (MedDRA) version 20.1 for study 1 and MedDRA version 24.0 for study 2. A TEAE was defined as an event that either occurred after administration of the study product but no later than the follow‐up visit or was present before the study product administration and increased in severity during the treatment period but no later than the follow‐up visit. Hereafter, TEAEs will be referred to as adverse events (AEs).
In both studies, supportive secondary safety endpoints comprised changes in vital signs, electrocardiogram parameters, clinical laboratory tests (including biochemistry and hematology), coagulation parameters, urine dipstick and urinalysis, physical examination, technical complaints (defined as any written, electronic, or oral communication that alleged a medicine or device defect), and the presence of anti‐zalfermin antibodies.
Biomarkers for bone turnover, including type I collagen X‐linked C‐telopeptide, osteocalcin, procollagen I intact N‐terminal propeptide, and bone alkaline phosphatase, as well as clinical laboratory tests for hormones (thyroid‐stimulating hormone [TSH], cortisol and insulin‐like growth factor 1), and lipids (beta‐hydroxybutyrate and free fatty acids), were also assessed in study 1, as a supportive secondary safety endpoint only.
AE data and vital signs were collected daily during the in‐house treatment period, at follow‐up visits on days 7, 11, 15, 22, 29 and 36 post‐dose, and additionally at in‐house visits on days 34 and 35 in Study 1. Electrocardiogram (ECG) assessments were also conducted daily during the in‐house visit and at all follow‐up visits except day −2 and day 34 in Study 1. Physical examinations were conducted at screening and on days 1, 5, and 36. Blood pressure and pulse were measured after ≥ 5 min rest with the subject lying in the supine position, and ECGs were recorded after the subject had rested for ≥ 10 min in the supine position.
2.4. PK Parameters Assessed and Time Points
From days 1 to 5, blood samples for the PK analysis of zalfermin were collected from each participant during the in‐house period and on days 7, 11, 15, 22, 29, and 36 post‐dose, across both studies. PK parameters assessed in both studies were maximum serum concentration (C max), time to C max (t max), half‐life (t 1/2), apparent clearance (CL/F), apparent volume of distribution (V/F), mean residence time, area under the curve (AUC) from time 0 to 168 h (AUC0–168h), AUC from time 0 to infinity (AUC0–inf), and AUC from time 0 to the last measurable serum concentration (AUC0–last). AUC from time 0 to 24 h (AUC0–24h) was assessed in study 1 only.
2.5. PK Sampling
Concentrations of zalfermin were assessed in serum using an in‐house immunoassay that was validated according to the US FDA guidance for bioanalytical method validation (2018) and the European Medicines Agency guideline on validation of bioanalytical methods (2011) [17, 18].
In studies 1 and 2, bioanalysis was performed using an ELISA assay. The lower limit of quantification was 1 and 2 nmol/L in studies 1 and 2, respectively. Further details of the bioanalysis assays and details of PK sampling are available in the Supporting Information Appendix.
2.6. PD Assessments and Sampling
In study 1, supportive secondary PD endpoints were changes in body weight and waist circumference, changes in fasting lipids (triglycerides [TG], total cholesterol, high‐density lipoprotein cholesterol [HDL‐C], low‐density lipoprotein cholesterol [LDL‐C], and very‐low‐density lipoprotein cholesterol [VLDL‐C]), changes in glucose metabolism (including fasting serum glucose, fasting serum insulin, fasting C‐peptide, fasting plasma glucagon, and glycated hemoglobin [HbA1c]) and changes in hormones (including leptin and soluble leptin receptor). In study 2, PD parameters assessed were changes in body weight, fasting lipids (TG, HDL‐C, and LDL‐C only), and fasting plasma glucose.
2.7. Statistical Analysis
In both studies, the bioanalysis of zalfermin was performed by the Department of Development Bioanalysis, Novo Nordisk A/S using non‐compartmental methods. Data were analyzed using SAS v9‐4 (TS1M2 and TS1M5). In both studies, analyses of safety endpoints were based on the safety analysis set (including all participants who had been exposed to at least one dose of the study product) and all safety endpoints were summarized using descriptive statistics. Analyzes of the PK and PD endpoints were based on the full analysis set (including all randomized participants who received at least one dose of the study product) and were summarized by treatment (and ethnicity in study 2) using descriptive statistics.
Across both studies, individual and mean curves for the concentration‐time profiles were plotted by treatment (and by ethnicity in study 2) using both linear and log‐linear concentration scales.
In study 1, for zalfermin, the PK endpoints AUC0–inf and C max were logarithmically transformed and analyzed separately by an analysis of variance model with dose as a factor, allowing for variation at the different dose levels. The estimated least square means were back‐transformed to the original scale and were presented together with 95% confidence intervals (CIs) and p‐values. Treatment ratios were presented with corresponding 95% CIs and p‐values. The dose proportionality of PK endpoints after multiple doses of zalfermin was explored by estimating the slope β in the linear regression model of the logarithm of the relevant endpoint versus log (dose). β = 1 indicated that the PK endpoint increased in a dose‐proportional manner with increasing dose. The estimated quantities 2β were reported with 95% CIs and p‐values.
Further details of the statistical analysis for the PK endpoints in study 2 can be found in the Supporting Information Appendix.
3. Results
3.1. Baseline Characteristics
In total, 56 and 42 participants were enrolled in study 1 and 2, respectively. Across both studies, 78 participants received a single dose of zalfermin. In study 1, the mean (standard deviation [SD]) age for the total population was 38 (9.1) years and the majority were White (66.1%). Mean body weight and BMI were 92.3 kg and 30.1 kg/m2, respectively (Table 1A). In study 2, 24 participants were Japanese and 18 were non‐Asian (White). Among Japanese participants, the mean (SD) age was 35 (11.0) years, mean body weight was 74.8 kg and mean BMI was 24.9 kg/m2. For non‐Asian participants, the mean (SD) age was 34 (9.0) years and mean body weight and BMI were 79.6 kg and 25.1 kg/m2, respectively (Table 1B).
TABLE 1.
Baseline characteristics for study 1 in healthy male participants and for study 2 in Japanese and non‐Asian healthy male participants.
| Study 1 | Zalfermin | Placebo | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Characteristic | 2 mg (n = 6) | 6 mg (n = 6) | 12 mg (n = 6) | 24 mg (n = 6) | 48 mg (n = 6) | 96 mg (n = 6) | 180 mg (n = 6) | (n = 14) | (N = 56) |
| Age, years | 42.8 (8.4) | 34.3 (10.4) | 41.8 (6.2) | 37.5 (11.2) | 37.8 (8.2) | 36.0 (8.4) | 33.5 (10.4) | 38.8 (9.3) | 38.0 (9.1) |
| Male, n (%) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 14 (100.0) | 56 (100.0) |
| Race, n (%) | |||||||||
| White | 4 (66.7) | 3 (50.0) | 3 (50.0) | 4 (66.7) | 5 (83.3) | 4 (66.7) | 3 (50.0) | 11 (78.6) | 37 (66.1) |
| Asian | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (16.7) | 1 (7.1) | 2 (3.6) |
| Black or African American | 2 (33.3) | 3 (50.0) | 3 (50.0) | 2 (33.3) | 1 (16.7) | 2 (33.3) | 2 (33.3) | 1 (7.1) | 16 (28.6) |
| Native Hawaiian or other Pacific Islander | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (7.1) | 1 (1.8) |
| Body weight, kg | 98.0 (14.1) | 91.8 (10.7) | 93.9 (11.2) | 92.6 (3.5) | 97.5 (13.9) | 90.8 (11.7) | 89.3 (6.3) | 89.1 (9.3) | 92.3 (10.3) |
| BMI, kg/m2 | 29.7 (2.1) | 30.3 (2.8) | 29.6 (3.1) | 29.7 (2.5) | 31.2 (1.1) | 30.2 (3.0) | 31.3 (1.6) | 29.7 (2.1) | 30.1 (2.3) |
| LDL cholesterol, mg/dL | 161 (23) | 149 (19) | 152 (35) | 144 (38) | 161 (23) | 140 (31) | 149 (57) | 131 (25) | 146 (32) |
| HDL cholesterol, mg/dL | 49 (12) | 43 (11) | 50 (8) | 50 (11) | 49 (6) | 45 (7) | 44 (9) | 42 (9) | 46 (9) |
| FGF21, pg/mL | 248.2 (114.7) | 256.7 (188.9) | 143.1 (93.44) | 151.7 (90.08) | 189.4 (125.6) | 191.0 (50.26) | 145.7 (144.6) | 308.2 (199.2) | 219.1 (151.9) |
| Study 2 | Zalfermin | Placebo | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Characteristic | 12 mg (n = 12) | 30 mg (n = 12) | 96 mg (n = 12) | (n = 6) | (N = 42) | |||||
| Japanese (n = 6) | Non‐Asian (n = 6) | Japanese (n = 6) | Non‐Asian (n = 6) | Japanese (n = 6) | Non‐Asian (n = 6) | Japanese (n = 6) | Non‐Asian (n = 0) | Japanese (n = 24) | Non‐Asian (n = 18) | |
| Age, years | 41 (11) | 38 (10) | 37 (10) | 29 (3) | 29 (9) | 35 (11) | 35 (11) | N/A | 35 (11) | 34 (9) |
| Male, n (%) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | 6 (100.0) | N/A | 24 (100.0) | 18 (100.0) |
| Race, n (%) | ||||||||||
| White | 0 (0.0) | 6 (100.0) | 0 (0.0) | 6 (100.0) | 0 (0.0) | 6 (100.0) | 0 (0.0) | N/A | 0 (0.0) | 18 (100.0) |
| Asian | 6 (100.0) | 0 (0.0) | 6 (100.0) | 0 (0.0) | 6 (100.0) | 0 (0.0) | 6 (100.0) | N/A | 24 (100.0) | 0 (0.0) |
| Body weight, kg | 76.2 (7.7) | 80.4 (7.4) | 71.9 (6.2) | 78.2 (9.3) | 75.6 (4.8) | 80.1 (8.0) | 75.4 (7.4) | N/A | 74.8 (6.4) | 79.6 (7.9) |
| BMI, kg/m2 | 25.3 (1.7) | 24.5 (1.0) | 24.6 (1.2) | 24.7 (2.2) | 24.7 (0.6) | 25.9 (1.5) | 25.0 (2.4) | N/A | 24.9 (1.5) | 25.1 (1.7) |
| LDL cholesterol, mg/dL | 110 (14) | 110 (20) | 110 (27) | 109 (18) | 116 (24) | 119 (30) | 114 (23) | N/A | 112 (21) | 113 (22) |
| HDL cholesterol, mg/dL | 51 (12) | 53 (8) | 45 (8) | 47 (6) | 50 (12) | 53 (6) | 47 (7) | N/A | 48 (10) | 51 (7) |
Note: Data are mean (standard deviation) unless otherwise stated.
Abbreviations: BMI, body mass index; FGF21, fibroblast growth factor 21; HDL, high‐density lipoprotein; LDL, low‐density lipoprotein; N/A, not applicable.
3.2. Safety
3.2.1. Adverse Events
In study 1, the number of AEs was greater in the 180 mg treatment group (11 events) compared with the lower dose cohorts (ranging from 0 to 5 events for each of the 2–96 mg groups). The proportion of participants recording any AEs was between 0% and 67% across all doses of zalfermin (Table 2). In study 2, the number of any AEs was also greater in the higher dose cohorts compared with the lower dose cohorts, with nine events recorded in each of the 96 mg dose groups in both the Japanese and non‐Asian populations (Table 3). In study 1, there were 10 gastrointestinal (GI) AEs observed in four participants with no clear pattern when assessed by preferred term (Table 2). In study 2, there were 17 GI AEs in 13 participants, the most frequent of which was diarrhea (Table 3). In both studies, AEs were mainly mild to moderate (Tables 2 and 3) and most AEs were of short duration, and all resolved by the end of the study. In addition, no serious AEs or deaths were observed. Only one participant in study 1 in the 12 mg dose group withdrew due to blood glucose increase, which was deemed unlikely to be related to the trial product and resolved after 5 days. No participants withdrew from study 2. In study 1, there were nine AEs in three participants possibly or probably related to zalfermin, with no pattern in reporting and were most frequent in the 180 mg dose group (Table 2). In study 2, there were 27 AEs possibly or probably related to zalfermin, and these were generally most frequent in the 96 mg dose group (Table 3). A complete listing of AEs by de‐identified participant for each study is reported in Table S1.
TABLE 2.
AEs after a single dose of zalfermin in healthy male participants (study 1).
| Zalfermin | Placebo | |||||||
|---|---|---|---|---|---|---|---|---|
| 2 mg (n = 6) | 6 mg (n = 6) | 12 mg (n = 6) | 24 mg (n = 6) | 48 mg (n = 6) | 96 mg (n = 6) | 180 mg (n = 6) | (n = 14) | |
| N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | |
| Any AE | 4 (66.7) | 4 | 0 | 0 | 1 (16.7) | 4 | 3 (50.0) | 4 | 2 (33.3) | 5 | 4 (66.7) | 4 | 4 (66.7) | 11 | 5 (35.7) | 5 |
| AEs leading to withdrawal | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| AEs possibly or probably related to trial product | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 2 | 0 | 0 | 2 (33.3) | 7 | 0 | 0 |
| Severity | ||||||||
| Severe | 0 | 0 | 0 | 0 | 1 (16.7) | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Moderate | 2 (33.3) | 2 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 | 2 (33.3) | 4 | 3 (21.4) | 3 |
| Mild | 2 (33.3) | 2 | 0 | 0 | 1 (16.7) | 1 | 3 (50.0) | 3 | 2 (33.3) | 4 | 4 (66.7) | 4 | 4 (66.7) | 7 | 2 (14.3) | 2 |
| AEs by system organ class and MedDRA Preferred Term | ||||||||
| Gastrointestinal disorders | 0 | 0 | 0 | 0 | 1 (16.7) | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 2 (33.3) | 6 | 1 (7.1) | 1 |
| Feces discolored | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Frequent bowel movements | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Nausea | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Vomiting | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 2 | 0 | 0 |
| Diarrhea | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Hemorrhoidal hemorrhage | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Hemorrhoids | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Hemorrhoids thrombosed | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Metabolism and nutrition disorders | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 |
| Decreased appetite | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Increased appetite | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 |
| Infections and infestations | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 |
| Gastroenteritis | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 |
| Investigations | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 2 (33.3) | 2 | 2 (33.3) | 2 | 1 (16.7) | 1 | 1 (7.1) | 1 |
| Blood glucose increase | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 |
| SBP decrease | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 |
| ALT increased | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Serum creatine phosphokinase increase | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| CRP increase | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Cortisol decreased | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
| Lipase increase | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| General disorders and administration site conditions | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 1 (7.1) | 1 |
| Early satiety | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Influenza‐like illness | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
| Injection site hemorrhage | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Vessel puncture site hematoma | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Eye disorders | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Eye pain | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Musculoskeletal and connective tissue disorders | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
| Back pain | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
| Nervous system disorders | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 2 (33.3) | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Headache | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dysgeusia | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Injury, poisoning, and procedural complications | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
| Laceration | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Injury | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Arthropod bite | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (7.1) | 1 |
Abbreviations: AE, treatment‐emergent adverse event; ALT, alanine aminotransferase; CRP, C‐reactive protein; E, number of events; MedDRA, Medical Dictionary for Regulatory Activities; SBP, systolic blood pressure.
TABLE 3.
AEs after a single dose of zalfermin in Japanese and non‐Asian healthy male participants (study 2).
| Japanese participants receiving zalfermin or placebo | Non‐Asian participants receiving zalfermin | ||||||
|---|---|---|---|---|---|---|---|
| 12 mg (n = 6) | 30 mg (n = 6) | 96 mg (n = 6) | Placebo (n = 6) | 12 mg (n = 6) | 30 mg (n = 6) | 96 mg (n = 6) | |
| N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | N (%) | E | |
| Any AE | 3 (50.0) | 4 | 2 (33.3) | 2 | 3 (50.0) | 9 | 1 (16.7) | 2 | 3 (50.0) | 3 | 2 (33.3) | 6 | 4 (66.7) | 9 |
| AEs leading to withdrawal | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| AEs possibly or probably related to trial product | 1 (16.7) | 1 | 1 (16.7) | 1 | 3 (50.0) | 8 | 1 (16.7) | 1 | 3 (50.0) | 3 | 2 (33.3) | 6 | 4 (66.7) | 7 |
| Severity | |||||||
| Severe | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Moderate | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Mild | 3 (50.0) | 3 | 2 (33.3) | 2 | 3 (50.0) | 9 | 1 (16.7) | 2 | 3 (50.0) | 3 | 2 (33.3) | 6 | 4 (66.7) | 9 |
| AEs by system organ class and MedDRA Preferred Term | |||||||
| Gastrointestinal disorders | 1 (16.7) | 1 | 1 (16.7) | 1 | 3 (50.0) | 5 | 1 (16.7) | 1 | 2 (33.3) | 2 | 2 (33.3) | 4 | 3 (50.0) | 3 |
| Diarrhea | 1 (16.7) | 1 | 1 (16.7) | 1 | 3 (50.0) | 5 | 1 (16.7) | 1 | 2 (33.3) | 2 | 2 (33.3) | 2 | 2 (33.3) | 2 |
| Frequent bowel movements | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 |
| Nausea | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Vomiting | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| General disorders and administration site conditions | 0 | 0 | 0 | 0 | 2 (33.3) | 2 | 0 | 0 | 0 | 0 | 2 (33.3) | 2 | 0 | 0 |
| Hunger | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Injection site pain | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Injection site reaction | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 |
| Metabolism and nutrition disorders | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 4 (66.7) | 4 |
| Increased appetite | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 4 (66.7) | 4 |
| Musculoskeletal and connective tissue disorders | 1 (16.7) | 1 | 1 (16.7) | 1 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 |
| Back pain | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Myalgia | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 |
| Periarthritis | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ear and labyrinth disorders | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 |
| Vertigo positional | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 (16.7) | 1 |
| Nervous system disorders | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Neuropathy peripheral | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Renal and urinary disorders | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Pollakiuria | 0 | 0 | 0 | 0 | 1 (16.7) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Abbreviations: AE, adverse event; ALT, alanine aminotransferase; E, number of events; MedDRA, Medical Dictionary for Regulatory Activities.
3.2.2. Local Tolerability
Injection site reactions were infrequent across all dose groups in both studies. In study 1, one event of injection site hemorrhage was reported in the 24 mg dose group. In study 2, one event each of injection site pain and injection site reaction was reported in the 96 mg Japanese dose group, and one injection site reaction event occurred in the non‐Asian 30 mg group. All events were mild and had resolved by day 36.
3.2.3. Vital Signs
Administration of zalfermin was not associated with changes in vital signs such as heart rate assessed via electrocardiogram or body temperature, across both studies (Tables S2 and S3). In study 1, two events of decrease in systolic blood pressure were reported in the 96 mg and 180 mg dose groups but were deemed unlikely to be related to zalfermin (Table 2). No AEs related to blood pressure were reported in study 2.
3.2.4. Clinical Laboratory Tests
There was a mild increase in lipase in one participant in the 2 mg group, an increase in serum glucose in two participants in the 12 mg and 96 mg groups, and a mild increase in serum creatine kinase in one participant in the 24 mg group. All were assessed as unlikely to be related to the administration of zalfermin. In the 48 mg group, one participant had a mild increase in alanine aminotransferase lasting for 7 days that was deemed to be possibly related to the administration of zalfermin, and one participant had a mild increase of C‐reactive protein (CRP) lasting for 7 days, which was assessed as unlikely to be related to zalfermin. These AEs based on clinical laboratory parameters were observed in study 1 (Table 2); no AEs from clinical laboratory parameters were observed in study 2 (Table 3). There were no obvious trends or developments in the clinical laboratory safety parameters associated with zalfermin administration.
3.2.5. Physical Examination
In study 1, there was one abnormal physical examination in the 2 mg group (hematoma, 5 cm on right forearm) at day 5; the event was mild and deemed unlikely to be related to zalfermin. There were no clinically relevant physical examination findings in study 2.
3.2.6. Technical Complaints
Across both studies, there were no clinically relevant findings for technical complaints (data not shown).
3.2.7. Anti‐Zalfermin Antibodies
In study 1, there was no occurrence of anti‐zalfermin antibodies. In study 2, at day 36, anti‐zalfermin antibodies cross‐reacting with endogenous FGF21 were detected in three Japanese participants and two non‐Asian participants, all of whom had received zalfermin 30 mg or 96 mg (Table S4). The PD biomarker levels, PK parameter values, and clinical findings for subjects with anti‐zalfermin antibodies were overall comparable with those for the other participants, indicating that the presence of these antibodies had no clinical impact.
3.3. Pharmacokinetics
Concentration‐time profiles for zalfermin are presented in Figure 1. In both studies, AUC0–inf and C max were dose‐proportional, and geometric mean t max ranged between 26 and 52 h across all zalfermin dose levels after dosing (Table 4), with a concentration of 0 being reached by approximately 672 h. In both studies, the t 1/2 of zalfermin was approximately 120 h (Table 4) with the exception of the 12 mg dose in study 2 for which it was approximately 135 h in both the Japanese and non‐Asian populations (Table 4). Overall, no apparent differences between Japanese and non‐Asian participants within the same zalfermin dose level were observed for any PK parameters (Table 4).
FIGURE 1.
Mean serum concentrations of zalfermin after a single dose in healthy male participants (study 1; 2–180 mg, N = 6 per group) (A, B) and in healthy Japanese and non‐Asian male participants (study 2; 12, 30, and 96 mg, N = 6 per group) (C, D). Values below the LLQ are imputed. LLQ, lower limit of quantification.
TABLE 4.
Pharmacokinetics after a single dose of zalfermin for study 1 in healthy male participants (A) and study 2 in Japanese and non‐Asian healthy male participants (B).
| (A) | Zalfermin | ||||||
|---|---|---|---|---|---|---|---|
| 2 mg (n = 6) | 6 mg (n = 6) | 12 mg (n = 6) | 24 mg (n = 6) | 48 mg (n = 6) | 96 mg (n = 6) | 180 mg (n = 6) | |
| C max (nmol/L) | 7.36 (33.0) | 24.5 (12.8) | 52.1 (23.9) | 107 (16.4) | 188 (24.6) | 480 (25.3) | 790 (22.3) |
| t max (h) | 38 (37.0) | 43 (53.6) | 44 (14.9) | 38 (31.8) | 51 (23.9) | 39 (28.0) | 45 (40.4) |
| t 1/2 (h) | 118 (21.9) | 123 (10.0) | 128 (11.1) | 116 (13.5) | 115 (10.3) | 124 (7.0) | 123 (9.7) |
| CL/F (L/h) | 0.0569 (27.6) | 0.0505 (19.2) | 0.0438 (25.7) | 0.0468 (12.1) | 0.0515 (19.7) | 0.0401 (21.4) | 0.0479 (20.3) |
| Vz/F (L) | 9.65 (36.0) | 9.00 (19.2) | 8.10 (16.8) | 7.81 (13.9) | 8.51 (22.4) | 7.18 (22.5) | 8.47 (17.7) |
| AUC0–24h (nmol × h/L) | 126 (35.6) | 358 (25.6) | 821 (26.9) | 1632 (17.8) | 2781 (25.0) | 7329 (27.2) | 11,819 (27.5) |
| AUC0–168h (nmol × h/L) | 983 (31.2) | 3175 (15.1) | 7190 (23.6) | 13,960 (13.3) | 24,985 (22.1) | 62,432 (24.5) | 101,458 (21.0) |
| AUC0–inf (nmol × h/L) | 1731 (27.6) | 5842 (19.2) | 13,484 (25.7) | 25,215 (12.1) | 45,897 (19.7) | 117,710 (21.4) | 184,967 (20.3) |
| (B) | Japanese participants receiving zalfermin | Non‐Asian participants receiving zalfermin | ||||
|---|---|---|---|---|---|---|
| 12 mg (n = 6) | 30 mg (n = 6) | 96 mg (n = 6) | 12 mg (n = 6) | 30 mg (n = 6) | 96 mg (n = 6) | |
| C max (nmol/L) | 44.7 (22.3) | 123 (18.0) | 381 (15.5) | 35.6 (22.4) | 120 (21.3) | 410 (10.6) |
| t max (h) | 39.0 (67.8) | 49.8 (9.1) | 35.2 (44.9) | 52.2 (80.5) | 43.1 (41.4) | 25.7 (16.7) |
| t 1/2 (h) | 134 (23.6) | 125 (10.0) | 121 (9.1) | 135 (14.0) | 117 (10.7) | 126 (2.8) |
| CL/F (L/h) | 0.0564 (19.6) | 0.0468 (21.9) | 0.0561 (14.0) | 0.0643 (27.7) | 0.0502 (18.0) | 0.0504 (15.0) |
| Vz/F (L) | 10.9 (40.8) | 8.42 (14.0) | 9.76 (16.3) | 12.5 (20.3) | 8.46 (24.7) | 9.15 (14.9) |
| AUC0–168h (nmol × h/L) | 5774 (24.6) | 16,615 (18.1) | 46,973 (13.7) | 4758 (24.1) | 15,689 (19.9) | 50,818 (11.9) |
| AUC0–inf (nmol × h/L) | 10,473 (19.6) | 31,542 (21.9) | 84,258 (14.0) | 9183 (27.7) | 29,412 (18.0) | 93,694 (15.0) |
Note: Data are geometric mean (CV).
Abbreviations: AUC0–24h/168h/inf, area under the concentration‐time curve from time zero to 24 h/168 h/infinity; CL/F, clearance; C max, maximum serum concentration; t 1/2, half‐life; t max, time to C max; Vz/F, apparent volume of distribution.
3.4. Pharmacodynamics
3.4.1. Body Weight and Waist Circumference
In study 1, no clinically relevant change from baseline in body weight or waist circumference was observed at the end of the study (Table S5). Weight loss and a reduction in waist circumference were observed at day 5 (during the in‐clinic period) but were not sustained by day 36, with the exception of the 180 mg dose group, in which body weight reduction was sustained from day 5 to day 36 (Table S5).
Results for body weight reduction in study 2 are presented in Table S6, where no clinically relevant decrease in body weight was observed at doses up to 96 mg.
3.4.2. Fasting Lipids
In both studies, reduced TG, LDL‐C, and VLDL‐C (assessed in study 1 only) levels and increased HDL‐C levels that appeared to be dose‐dependent were observed after a single dose of zalfermin (Figure 2). Changes in LDL‐C were sustained for up to 29 days after the single s.c. dose administration of zalfermin, whereas TG and VLDL‐C changes were sustained for up to approximately 29 days in the higher dose cohorts (12–180 mg) and 5 days in the lower dose cohorts (2 and 6 mg). Changes in HDL‐C were sustained up to day 15 for zalfermin 12–96 mg and up to day 29 for the 180 mg cohort (Figure 2). In study 1, maximum percentage changes in TG, LDL‐C, HDL‐C, and VLDL‐C were −55%, 29%, 36% and −55%, respectively, across all zalfermin treatment groups (Table 5).
FIGURE 2.
Change from baseline in serum lipids after a single dose of zalfermin in healthy male participants (study 1; 2–180 mg, N = 6 per group) (A), and in healthy Japanese and non‐Asian male participants (study 2; 12, 30, and 96 mg, N = 6 per group) (B). All data are geometric mean. HDL‐C, high‐density lipoprotein cholesterol; JP, Japanese; LDL‐C, low‐density lipoprotein cholesterol; NA, non‐Asian; VLDL‐C, very low‐density lipoprotein.
TABLE 5.
Change in lipids (ratio to baseline) in healthy male participants (study 1).
| Zalfermin | Placebo | |||||||
|---|---|---|---|---|---|---|---|---|
| 2 mg (n = 6) | 6 mg (n = 6) | 12 mg (n = 6) | 24 mg (n = 6) | 48 mg (n = 6) | 96 mg (n = 6) | 180 mg (n = 6) | (n = 14) | |
| Triglycerides | ||||||||
| Day 5 | 0.66 (33.7) | 0.70 (18.5) | 0.56 (18.5) | 0.60 (11.3) | 0.54 (15.1) | 0.59 (14.3) | 0.51 (18.2) | 0.80 (18.5) |
| Day 15 | 0.90 (29.2) | 0.96 (28.6) | 0.55 (18.1) | 0.64 (42.6) | 0.63 (56.5) | 0.51 (12.4) | 0.45 (15.4) | 1.04 (45.3) |
| Day 29 | 1.07 (28.0) | 0.97 (48.6) | 0.78 (34.0) | 0.69 (37.5) | 0.61 (71.3) | 0.61 (24.9) | 0.71 (27.9)* | 0.95 (41.7) |
| Day 36 | 0.97 (21.3) | 0.99 (19.5) | 0.89 (26.4) | 0.91 (25.9) | 0.90 (21.1) | 0.93 (18.1) | 0.89 (27.5)* | 0.98 (17.8) |
| LDL cholesterol | ||||||||
| Day 5 | 1.03 (4.3) | 0.98 (8.9) | 1.00 (8.9) | 0.96 (9.1) | 0.89 (6.6) | 0.89 (11.2) | 0.91 (11.2) | 1.02 (9.7) |
| Day 15 | 0.85 (10.0) | 0.81 (6.0) | 0.71 (10.7) | 0.78 (2.3) | 0.72 (16.9) | 0.71 (16.0) | 0.73 (21.2) | 0.89 (11.5) |
| Day 29 | 0.94 (17.9) | 0.90 (18.9) | 0.71 (16.3) | 0.89 (16.6) | 0.75 (25.8) | 0.76 (11.8) | 0.83 (9.3)* | 0.95 (11.8) |
| Day 36 | 1.05 (6.6) | 1.03 (10.5) | 0.97 (7.1) | 1.04 (6.8) | 1.01 (18.9) | 0.96 (5.5) | 0.98 (21.5)* | 1.10 (10.8) |
| HDL cholesterol | ||||||||
| Day 5 | 1.01 (7.7) | 1.03 (7.5) | 1.04 (9.4) | 1.13 (8.3) | 1.03 (7.0) | 1.14 (4.7) | 1.16 (7.1) | 0.94 (8.4) |
| Day 15 | 0.99 (11.2) | 1.21 (15.8) | 1.15 (8.3) | 1.27 (13.5) | 1.16 (19.2) | 1.29 (14.0) | 1.30 (12.3) | 1.01 (12.7) |
| Day 29 | 0.98 (14.7) | 1.17 (23.0) | 1.05 (13.2) | 1.16 (11.1) | 1.09 (21.0) | 1.23 (14.3) | 1.36 (5.9)* | 1.02 (11.8) |
| Day 36 | 0.96 (5.5) | 1.19 (12.3) | 1.03 (11.1) | 1.08 (11.7) | 1.06 (12.8) | 1.24 (6.2) | 1.29 (11.7)* | 1.03 (5.4) |
| VLDL cholesterol | ||||||||
| Day 5 | 0.67 (35.2) | 0.70 (18.4) | 0.55 (20.2) | 0.61 (11.4) | 0.54 (15.3) | 0.59 (15.1) | 0.51 (17.4) | 0.79 (18.7) |
| Day 15 | 0.92 (30.1) | 0.95 (28.8) | 0.55 (18.7) | 0.65 (42.8) | 0.63 (56.2) | 0.51 (12.7) | 0.45 (13.5) | 1.04 (46.3) |
| Day 29 | 1.08 (30.3) | 0.98 (47.5) | 0.77 (34.8) | 0.69 (36.4) | 0.61 (72.0) | 0.61 (23.3) | 0.71 (27.9)* | 0.94 (41.8) |
| Day 36 | 0.98 (21.9) | 1.00 (20.4) | 0.90 (25.8) | 0.92 (26.3) | 0.91 (22.3) | 0.94 (17.6) | 0.88 (27.8)* | 0.98 (18.5) |
Note: Data are geometric mean (CV).
Abbreviations: CV, coefficient of variation; HDL, high‐density lipoprotein; LDL, low‐density lipoprotein; VLDL, very‐low‐density lipoprotein.
n = 5.
In study 2, maximum percentage changes in TG, LDL‐C, and HDL‐C were −55%, −25%, and 45%, respectively, across all zalfermin treatment groups (Table S7).
There were no significant changes for hormones, glucose metabolism, or bone turnover markers; results are presented in Tables S8–S12.
4. Discussion
This is the first in‐human study to evaluate the safety, tolerability, PK, and PD of zalfermin, a novel FGF21 analog, via a single ascending dose regimen. The majority of AEs across both studies included GI‐related AEs and increased appetite and were mild to moderate, with no serious AEs or deaths and no clinically relevant immunogenicity.
Several other FGF21 analogs have been clinically tested in phase 1 and 2 trials in humans (PF‐05231023, LY2405319, pegbelfermin, efruxifermin, pegozafermin, and efimosfermin) [14, 15, 19, 20, 21, 22, 23, 24]. In these studies, AEs also consisted of changes in appetite and GI‐related events, which were transient, as well as injection site‐related events [14, 15, 19, 20, 22, 23, 24]. Thus, the clinical safety profile of zalfermin observed in the current analysis is largely consistent with the FGF21 analog class. In preclinical studies, single doses of the FGF21 analog PF‐05231023 have been associated with increases in blood pressure, water intake, and urine output [25]. In study 1, two patients experienced a decrease in systolic blood pressure that was deemed unlikely to be related to zalfermin, and across both studies there were no clinically relevant changes in laboratory safety parameters, including urine volume, following zalfermin administration. Study 1 enrolled a small proportion of Asian participants (one participant each in the placebo and 180 mg dose groups). A second study was conducted to provide safety and PK data in Japanese people to support further clinical development of zalfermin in Japan, and to confirm the dose proportionality of zalfermin at a higher product strength (50 mg/mL) and lower dose volume compared with study 1 (15 mg/mL). Non‐Asian subjects were enrolled into study 2 to allow direct comparison of PK properties with the 50 mg/mL formulation across ethnicities, and as such no placebo was included in these patients as a control.
PK parameters were generally similar between the two studies, specifically for the 12 mg and 96 mg doses, for which the C max and AUC0–inf geometric means (CV) were comparable between both studies. With similar exposures to zalfermin observed for the two study populations, these results suggest that intrinsic factors (e.g., ethnicity‐related genetics) do not appear to affect the PK of zalfermin. In both studies, dose proportionality was established for C max and AUC0–inf. No clinically relevant difference in dose proportionality was observed between Japanese and non‐Asian participants. Zalfermin had a low Vz/F in both studies (7.2–12.5 L) with no clear pattern across dose levels, supporting a linear PK profile and indicating that zalfermin is primarily present in plasma. The geometric mean of t max ranged from 38 to 51 h in study 1, and 35 to 50 h for Japanese participants and 26 to 52 h for non‐Asian participants in study 2, across all dose levels. The t 1/2 of zalfermin was similar across dose cohorts and studies, ranging from 115 to 135 h. Therefore, the approximate t 1/2 of zalfermin of 120 h (5 days) determined across both studies is supportive of sustained PD activity within a once‐weekly dosing regimen. Of note, efimosfermin is currently the only FGF21 analog in development with a longer t 1/2 compared with zalfermin and is expected to be the first once‐monthly FGF21 analog [23]. The current results show that the dosing regimen for zalfermin is more comparable to efruxifermin and pegozafermin, and they suggest that zalfermin may sustain PD activity for marginally longer than these counterparts due to its slightly longer t 1/2 [15, 26, 27]. Chemical modification of peptide and protein by addition of a fatty acid moiety has been shown to extend the t 1/2 of native protein and peptides [10], exemplified by insulin degludec and semaglutide [28, 29]. The albumin binding properties prevent renal excretion and, in the case of zalfermin, also prevent C‐terminal degradation [10]. Later‐stage clinical data are required to assess whether zalfermin has superior efficacy to other FGF21 analogs such as efruxifermin, pegozafermin, and efimosfermin.
Although no clinically meaningful weight loss was observed with zalfermin across both studies, this was expected given that other FGF21 analogs have not demonstrated significant body weight reduction in previous first‐in‐human single ascending dose studies [15, 19]. However, previous studies of FGF21 analogs have shown improvements in lipid profiles, such as the decreases in TG of approximately 40%–70% observed with pegozafermin 9–36 mg, efruxifermin 70–140 mg, LY2405319 10–20 mg, PF‐05231023 200 mg, and efimosfermin 300 mg [14, 15, 19, 20, 23]. By comparison, in this study, zalfermin achieved a maximum decrease in TG of −55% in the 180 mg dose group at day 15. Improvements in lipids, in the current study, generally occurred around day 15 to day 29 and showed a trend of returning to baseline by day 36. In a study of efruxifermin dosed once or twice weekly, the greatest improvement in lipids generally occurred around day 15 and was sustained up to day 29 before returning toward baseline levels by day 57 [15]. However, these results should be interpreted with caution, given that the efruxifermin trial was a multiple ascending dose study of longer duration. The improved lipid profile observed in our study is encouraging for the further development of zalfermin for the treatment of cardiometabolic diseases such as dyslipidemia.
Previously, efruxifermin demonstrated an effect on MASH resolution and fibrosis improvement after 52 weeks in participants with MASH and fibrosis stage F2 or F3 [24]. In addition, in a 24‐week, Phase IIb study of pegozafermin 15 mg and 30 mg, MASH resolution without worsening of fibrosis was observed for both doses (37% and 23% MASH resolution, respectively, and 22% and 26% fibrosis improvement, respectively) [16]. A Phase II study (NCT05016882) of zalfermin with/without semaglutide combination therapy is in progress to determine the effect on MASH resolution and fibrosis improvement [30]. Combination therapy with semaglutide to drive sustained body weight loss through reduced energy intake may potentiate the cardiometabolic effect of zalfermin through different mechanisms of action [31, 32]. The study will elucidate whether the combination of zalfermin with semaglutide provides additional benefits beyond monotherapy for the treatment of MASH.
In these two studies, there were no clinically relevant changes in glucose metabolism parameters from baseline to follow‐up, which was expected given that this was a single ascending dose study and that the populations of both studies were normoglycemic [14, 15]. Similar results were seen in a single ascending dose study of pegozafermin in healthy adults, with no notable effects on serum glucose or insulin levels at any of the doses studied [20].
Generally, FGF21 analogs have been shown to lower HbA1c and improve insulin sensitivity [15, 33]. For example, the FGF21 analog efruxifermin administered once weekly for 28 days showed sustained PD effects on insulin sensitivity and lipid metabolism in participants with overweight/obesity and T2D [15]. However, further studies into zalfermin and its effects on insulin sensitivity and blood glucose levels at multiple ascending doses may be warranted to determine whether zalfermin has the potential to treat and improve not only MASH but also a variety of metabolic disorders such as obesity and T2D.
This study had some limitations, including the relatively small sample sizes, the short duration of both studies, and the exclusion of female participants. Furthermore, the inclusion of participants with overweight/obesity who were otherwise healthy does not allow us to fully explore the effectiveness of zalfermin in a population with disease burden; this is beyond the scope of the Phase I study. Accordingly, later‐phase clinical studies with a longer follow‐up period will be needed to support the safety and efficacy of zalfermin in larger and more clinically diverse populations. Assay cross‐reactivity from endogenous FGF21 is also a possible limitation of this study; however, median values of circulating FGF21 (~100–200 pg/mL in healthy individuals, and up to 8 ng/mL in individuals with metabolic disease) [34, 35] are below the LLQ, and as such endogenous circulating FGF21 is unlikely to have interfered with zalfermin quantification.
In conclusion, the novel FGF21 analog zalfermin had an acceptable safety profile at all dose levels tested, with comparable systemic exposures and outcomes in Japanese and non‐Asian populations. The linear PK profile appears compatible with a once‐weekly dose regimen, and the PD profile suggests that zalfermin has promise to join the treatment armamentarium for cardiometabolic diseases such as MASH and other cardiometabolic diseases. The results obtained from this study provide a basis for the further clinical development of zalfermin.
Author Contributions
K.D., M.H.F., R.R.‐M., J.S.H., J.O.C., M.A., M.S.P., S.L.L., O.B., S.T., and B.A. wrote the manuscript. K.D., M.H.F., J.S.H., M.A., M.S.P., S.T., and B.A. designed the research. K.D., M.H.F., R.R.‐M., J.S.H., J.O.C., M.A., S.T., C.K., and B.A. performed the research. K.D., R.R.‐M., J.S.H., M.A., M.S.P., S.T., and B.A. analyzed the data. S.L.L. and O.B. contributed new reagents and analytical tools.
Funding
These studies were sponsored by Novo Nordisk A/S.
Conflicts of Interest
K.D., M.H.F., R.R.‐M., J.S.H., J.O.C., M.S.P., S.L.L., O.B., S.T., and B.A. are all employees and shareholders of Novo Nordisk A/S. M.A. is an employee of Gubra A/S. C.K. is an employee and shareholder of ICON plc.
Supporting information
Data S1: cts70435‐sup‐0001‐supinfo01.docx.
Table S1: AEs by individual participants in study 1 and 2.
Table S2: Change from baseline in heart rate, body temperature, and systolic blood pressure following a single dose of zalfermin in healthy male participants (study 1).
Table S3: Change from baseline in heart rate, body temperature, and systolic blood pressure following a single dose of zalfermin in Japanese and non‐Asian healthy male participants (study 2).
Table S4: Occurrence of anti‐zalfermin antibodies in Japanese and non‐Asian healthy male participants (study 2).
Table S5: Percentage change from baseline in body weight and waist circumference following a single dose of zalfermin in healthy male participants (study 1).
Table S6: Percentage change from baseline in body weight following a single dose of zalfermin in Japanese and non‐Asian healthy male participants (study 2).
Table S7: Change in lipids (ratio to baseline) in Japanese and non‐Asian healthy male participants (study 2).
Table S8: Change in hormones (ratio to baseline) in healthy male participants (study 1).
Table S9: Change from baseline in glucose metabolism parameters in healthy male participants (study 1).
Table S10: Change from baseline in glucose metabolism parameters in Japanese and non‐Asian healthy male participants (study 2).
Table S11: Change from baseline in beta‐hydroxybutyrate and free fatty acids in healthy male participants (study 1).
Table S12: Change from baseline in biomarkers of bone turnover in healthy male participants (study 1).
Figure S1: Study designs for study 1 (A) and study 2 (B).
Acknowledgments
The authors thank the study participants, the investigators, and study site staff who conducted the study. Medical writing support was provided by Casey McKeown RVN, FdSc, and Liam Gillies PhD, of Titan, Apollo, OPEN Health Communications, and was funded by Novo Nordisk, in accordance with Good Publication Practice (GPP) guidelines (www.ismpp.org/gpp‐2022).
Dahl K., Friedrichsen M. H., Ribel‐Madsen R., et al., “Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of the Novel Long‐Acting FGF21 Analog Zalfermin,” Clinical and Translational Science 18, no. 12 (2025): e70435, 10.1111/cts.70435.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data S1: cts70435‐sup‐0001‐supinfo01.docx.
Table S1: AEs by individual participants in study 1 and 2.
Table S2: Change from baseline in heart rate, body temperature, and systolic blood pressure following a single dose of zalfermin in healthy male participants (study 1).
Table S3: Change from baseline in heart rate, body temperature, and systolic blood pressure following a single dose of zalfermin in Japanese and non‐Asian healthy male participants (study 2).
Table S4: Occurrence of anti‐zalfermin antibodies in Japanese and non‐Asian healthy male participants (study 2).
Table S5: Percentage change from baseline in body weight and waist circumference following a single dose of zalfermin in healthy male participants (study 1).
Table S6: Percentage change from baseline in body weight following a single dose of zalfermin in Japanese and non‐Asian healthy male participants (study 2).
Table S7: Change in lipids (ratio to baseline) in Japanese and non‐Asian healthy male participants (study 2).
Table S8: Change in hormones (ratio to baseline) in healthy male participants (study 1).
Table S9: Change from baseline in glucose metabolism parameters in healthy male participants (study 1).
Table S10: Change from baseline in glucose metabolism parameters in Japanese and non‐Asian healthy male participants (study 2).
Table S11: Change from baseline in beta‐hydroxybutyrate and free fatty acids in healthy male participants (study 1).
Table S12: Change from baseline in biomarkers of bone turnover in healthy male participants (study 1).
Figure S1: Study designs for study 1 (A) and study 2 (B).