Model-informed dose selection for an investigational human epidermal growth factor receptor 2 antibody-drug conjugate FS-1502 in patients with human epidermal growth factor receptor 2-expressing advanced malignant solid tumours.

AIMS: The dose-escalation phase (phase Ia study) of a novel human epidermal growth factor receptor 2 (HER2) antibody-drug conjugate (ADC) FS-1502 included a dose range from 0.1 to 3.5 mg/kg in HER2-expressing advanced malignant solid tumours. However, the defined maximum tolerated dose was not reached. This model-informed approach integrated population pharmacokinetic (PopPK) modelling and exposure-response (E-R) analysis to facilitate dose selection for phase II. METHODS: The PopPK model was constructed using PK data from 109 Chinese patients who received doses of 0.1-3.5 mg/kg FS-1502 every 3 (Q3W) or 4 weeks during a phase I dose-escalation and dose expansion trial. The structural model consisted of compartment models for FS-1502 and unconjugated monomethyl auristatin F. E-R was explored for the percentage change in tumour size, overall response rate and treatment-related adverse events. RESULTS: A semi-mechanistic 2-analyte PopPK model was developed. The FS-1502 PK data were best described by a 2-compartment PK model with parallel linear and nonlinear Michaelis-Menten eliminations. The PK of unconjugated monomethyl auristatin F was described by a 2-compartment model with first-order elimination. E-R analysis supported the clinically meaningful efficacy of FS-1502 at 2.3 mg/kg and above. However, 2.3 mg/kg Q3W was considered to have a better benefit-risk balance due to a lower incidence of safety events without a significant reduction in efficacy compared to 3.0 mg/kg Q3W. CONCLUSION: This PopPK and E-R analysis guided the recommended phase II dose selection of 2.3 mg/kg Q3W and supported body weight-based dosing for an investigational HER2 ADC FS-1502.

Phase 1 dose-escalation study to evaluate the safety, tolerability, pharmacokinetics, and anti-tumor activity of FCN-159 in adults with neurofibromatosis type 1-related unresectable plexiform neurofibromas.

BACKGROUND: Surgery is a common treatment strategy for patients with neurofibromatosis type 1 (NF1)-related plexiform neurofibroma (PN) and has limited efficacy. FCN-159 is a novel anti-tumorigenic drug via selective inhibition of MEK1/2. This study assesses the safety and efficacy of FCN-159 in patients with NF1-related PN. METHODS: This is a multicenter, open-label, single-arm, phase I dose-escalation study. Patients with NF1-related PN that was non-resectable or unsuitable for surgery were enrolled; they received FCN-159 monotherapy daily in 28-day cycles. RESULTS: Nineteen adults were enrolled in the study, 3 in 4 mg, 4 in 6 mg, 8 in 8 mg, and 4 in 12 mg. Among patients included in dose-limiting toxicity (DLT) analysis, DLTs (grade 3 folliculitis) were reported in 1 of 8 patients (16.7%) receiving 8 mg and 3 of 3 (100%) patients receiving 12 mg. The maximum tolerated dose was determined to be 8 mg. FCN-159-related treatment-emergent adverse events (TEAEs) were observed in 19 patients (100%); most of which were grade 1 or 2. Nine (47.4%) patients reported grade 3 study-drug-related TEAEs across all dose levels, including four experiencing paronychia and five experiencing folliculitis. Of the 16 patients analyzed, all (100%) had reduced tumor size and six (37.5%) achieved partial responses; the largest reduction in tumor size was 84.2%. The pharmacokinetic profile was approximately linear between 4 and 12 mg, and the half-life supported once daily dosing. CONCLUSIONS: FCN-159 was well tolerated up to 8 mg daily with manageable adverse events and showed promising anti-tumorigenic activity in patients with NF1-related PN, warranting further investigation in this indication. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04954001. Registered 08 July 2021.

Phase 1a study of the CDK4/6 inhibitor, FCN-437c, in Chinese patients with HR + /HER2- advanced breast cancer.

Purpose This phase 1a, first-in-human study assessed the safety, maximum tolerated dose (MTD), pharmacokinetics (PK), and antitumor activity of FCN-437c, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor. Methods The study enrolled female patients with HR + /HER2- advanced breast cancer (BC) who failed standard of care therapy. A 3 + 3 dose-escalation design was utilized with a starting dose of 50 mg daily for 3 weeks on and 1 week off treatment in 28-day cycles. Patients received escalating doses of FCN-437c monotherapy (50, 100, 200, 300, and 450 mg). Results Seventeen patients received FCN-437c 50 mg (n = 3), 100 mg (n = 3), 200 mg (n = 3), 300 mg (n = 6), and 450 mg (n = 2). Two patients who received the 450-mg dose experienced dose-limiting toxicities (DLTs; grade 4 thrombocytopenia and neutropenia); no DLT was observed at any other dose level. Frequently reported treatment-emergent adverse events (TEAEs) of any grade were hematological: leukopenia (94.1%), neutropenia (88.2%), anemia (64.7%), and thrombocytopenia (47.1%). Grade 3-4 TEAEs included neutropenia (64.7%) and leukopenia (47.1%). Exposure of FCN-437c increased almost proportionally to doses ranging from 50 to 200 mg. At doses from 200 to 450 mg, there appeared to be a trend of saturation. The MTD was determined to be 300 mg. Of 15 patients with measurable disease, nine (60.0%) patients experienced stable disease; no complete or partial responses were observed. Conclusions These results established an acceptable safety profile for FCN-437c in patients with advanced BC, and there were no unexpected signals relative to other CDK4/6 inhibitors. (NCT04488107; July 13, 2020).

HER2-targeting antibody drug conjugate FS-1502 in HER2-expressing metastatic breast cancer: a phase 1a/1b trial.

Currently approved HER2-targeting antibody-drug conjugates (ADCs) for HER2-positive breast cancer (BC) are associated with safety concerns. In this multicenter, single-arm, dose-escalation (phase 1a) and dose-expansion (phase 1b) phase 1 trial (NCT03944499), patients with HER2-expressing advanced solid tumors received FS-1502 (an anti-HER2 ADC) with a 3 + 3 design in phase 1a; patients with metastatic HER2-positive BC received FS-1502 at the recommended phase 2 dose (RP2D) in phase 1b. The primary end points were dose-limiting toxicities (DLTs), maximum tolerated dose (MTD) and RP2D for phase 1a and objective response rate (ORR) for phase 1b. A total of 150 patients with HER2-expressing solid tumors (n = 5) and BC (n = 145) were enrolled (female, n = 146, 97.3%). One DLT each was reported at 3.0 and 3.5 mg/kg; the MTD was not reached. The RP2D was 2.3 mg/kg once every 3 weeks. Five (3.3%) patients experienced pneumonitis; four (2.7%) had grade 3 reversible ocular events. Of 67 HER2-positive BC patients receiving the RP2D, the best ORR was 53.7% (95% CI, 41.1-66.0%), including PRs confirmed (confirmed ORR, 37.5%) and pending for confirmation. FS-1502 was well tolerated with limited ocular and pulmonary findings and demonstrated promising antitumor activity in HER2-positive BC patients.

Population pharmacokinetics of FCN-159, a MEK1/2 inhibitor, in adult patients with advanced melanoma and neurofibromatosis type 1 (NF1) and model informed dosing recommendations for NF1 pediatrics.

Objective: FCN-159 is a highly active mitogen-activated extracellular signal-regulated kinase 1/2 (MEK1/2) inhibitor in patients with advanced melanoma and neurofibromatosis type 1 (NF1). We report a population pharmacokinetic (PopPK) model-based analysis of FCN-159 and its application to inform dose selection for NF1 pediatric trials. Methods: PK data collected from patients with advanced melanoma and NF1 in two clinical studies (NCT03932253 and NCT04954001) were analyzed using a non-linear mixed effects model. The adult model was adapted by incorporating allometric scaling for PK projection in 2-17 years old children. Pediatric exposure in different body surface area (BSA) bins was simulated to identify nominal doses (i.e., dose amounts given as integers) and BSA bin cutoffs to achieve exposure comparable to adults' optimal exposure across the entire pediatric BSA range. Results: The final dataset consisted of 45 subjects with a total of 1030 PK samples. The PK of FCN-159 was well-described by a 2-compartment model with first-order linear elimination and delayed first-order absorption. Covariates, including BSA, age, sex, albumin, total protein, and cancer type, were identified as statistically significant predictors of FCN-159 disposition. Simulations based on the final model projected daily doses of 4 mg/m2 QD with optimized BSA bin cutoffs would allow fixed nominal doses within each bin and result in steady state exposure approximating the adult exposure observed at the recommended phase 2 dose (RP2D) in NF1, which is 8 mg QD. Conclusion: The developed population PK model adequately described the PK profile of FCN-159, which was adapted using allometric scaling to inform dose selection for NF1 pediatric trials.

Effect of Food (Low and High Fat) on Pharmacokinetics of FCN-159, a Selective MEK Inhibitor, in Healthy Chinese Males.

INTRODUCTION: FCN-159 is a novel, oral, potent, selective MEK1/2 inhibitor in clinical development for the treatment of NRAS-mutant advanced melanoma and neurofibromatosis type 1. We investigated the effect of food on the pharmacokinetics (PK), safety, and tolerability of FCN-159. METHODS: In this single-center, open-label, phase 1 study with a three-period, three-sequence, crossover design, healthy Chinese male subjects (n = 24) were randomized (1:1:1) to receive a single, oral 8 mg dose of FCN-159 in the fasted state (overnight, > 10 h), and with a low-fat and a high-fat meal, separated by a 10-day washout. PK parameters including time to maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) were compared using geometric least-squares mean ratios (GLSMR), with the fasted state as the reference. A 90% CI for the GLSMR within 80-125% indicated no significant food effect. RESULTS: A low-fat meal (n = 23) did not affect the PK profile of FCN-159: G LSMR for AUC from time 0 to t (AUC0-t), 106.9% (90% CI 99.9-114.4%); AUC from time 0 to infinity (AUC0-∞), 106.8% (90% CI 100.0-114.0%); Cmax, 96.4% (90% CI 83.9-110.8%). A high-fat meal (n = 24) did not affect exposure to FCN-159 (GLSMR for AUC0-t, 99.4%; 90% CI 99.0-106.3%; AUC0-∞, 99.5 5%; 90% CI 93.2-106.1%), but modestly reduced Cmax by 15% (GLSMR 84.9%; 90% CI 74.0-97.3%). Both the low-fat and high-fat meals slightly prolonged the median time to Cmax by 0.5 h (90% CI 0.5-1.0 h). FCN-159 was generally well tolerated, with a lower incidence of treatment-emergent adverse events following administration in the fasted state than with a low-fat or high-fat meal (20.8%, 39.1%, and 37.5%, respectively). CONCLUSION: Food did not affect the PK profile of FCN-159 to a clinically meaningful extent compared with administration in the fasted state.

Effect of High-Fat Food on the Pharmacokinetic Profile and Safety of SAF-189s, an ALK/ROS1 Inhibitor, in Healthy Chinese Adults.

BACKGROUND AND OBJECTIVES: This study was conducted to investigate the effect of high-fat meals on the pharmacokinetics (PK) and safety profile of SAF-189s, a novel ALK/ROS1 inhibitor. METHODS: This was a single-center, phase I, open-label, crossover study in which healthy adults (≥18 years) were randomized (1:1) to two sequences of SAF-189s administration (fasted-fed or fed-fasted) separated by a 14-day washout. After a ≥10-h overnight fast, volunteers received SAF-189s 160 mg orally in a fasted state or 30 min after a high-fat, high-calorie meal. Similarity of pharmacokinetic parameters was concluded if the 90% CI for the geometric mean ratio (GMR) between the fed and fasted group fell within the predefined range of 0.80-1.25. RESULTS: In total, 24 subjects were enrolled and 23 completed the study. SAF-189s maximum plasma concentration (Cmax; GMR: 109.1% [90% CI 103.1-115.4]) was comparable under fed (high-fat meal, n = 24) versus fasted (n = 23) conditions, with no effect on area under the plasma concentration-time curve from time 0 to t (AUC0-t; GMR: 105.1% [90% CI 100.3-110.2]) and AUC from time 0 to infinity (AUC0-∞; GMR: 105.5% [90% CI, 100.6-110.6]). In both groups, the median time to maximum plasma concentration (tmax) was around 6 h and mean plasma half-life (t½) was around 35 h. Fed administration led to a lower incidence of treatment-emergent adverse events (TEAEs; 29.2% vs 54.2%), including gastrointestinal disorders (4.2% vs 41.7%) and headache (0.0% vs 12.5%), versus fasted administration. CONCLUSIONS: A high-fat meal had minimal effect on the pharmacokinetic profile of SAF-189s compared with a fasted state following a single dose of 160 mg. Administration with a high-fat meal led to a lower incidence of TEAEs.

Pulsed infrared stimulation evoked electrical potential in mouse vestibular system.

To improve accuracy of VsEP and avoid the inherent limitation of mechanical vibration, we designed an infrared optical stimulation approach to stimulate mouse vestibular system and measured the evoked potential. IR pulses (1871 nm, 30 pps and 100 µs pulse width) were delivered to mice with different vestibular dysfunction levels and the evoked potential was recorded. The result suggests that the amplitude and latency of the IR-evoked potential (IR-VsEP) were significantly associated with vestibular function integrity. Immunofluorescence staining confirmed that magnitude of IR-VsEP decreased was consistent with the loss of HCs. Micro-CT imaging revealed that the optical fiber was orientating towards the vestibular system. Taken together, we found that: 1) IR stimulation can generate VsEP evoked potential in vestibular system (IR-VsEP), which can be potentially used for vestibular function evaluation; 2) intact HCs and fully functional synaptic transmission are crucial for efficient IR-induced vestibular system stimulation.

A phase I study of FCN-411, a pan-HER inhibitor, in EGFR-mutated advanced NSCLC after progression on EGFR tyrosine kinase inhibitors.

BACKGROUND: There are no approved epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for EGFR-mutated non-small cell lung cancer (NSCLC) without EGFR T790M mutation after progression on first- or second-generation EGFR-TKIs. METHODS: We conducted this phase I, open-label, multicenter, dose-escalation/dose-expansion study to evaluate the safety, tolerability, antitumor activity, and pharmacokinetics of FCN-411, a TKI targeting EGFR, HER2, and HER4, in patients with EGFR-mutated advanced NSCLC whose disease had progressed during treatment of EGFR-TKIs. Adult patients with stage IIIB-IV NSCLC harboring EGFR mutations (exon 18/19/20/21) who had progressed on prior EGFR-TKIs were enrolled. In the dose-escalation phase, patients received 4 mg, 8 mg, 12 mg, and 16 mg FCN-411 once daily until the maximum tolerated dose (MTD). In the dose-expansion phase, patients received FCN-411 at the recommended phase II dose (RP2D) continuously in 21-day cycles. The primary endpoints were safety, tolerability, MTD, and RP2D. RESULTS: From July 23, 2018 to September 29, 2020, 77 patients were enrolled, including 30 with EGFR T790M mutation in tumor tissues. The cut-off date was February 1, 2021. No dose-limiting toxicities were observed. The most common grade ≥ 3 treatment-emergent adverse events among all patients were diarrhea (8; 10.4%) and dermatitis acneiform (7; 9.1%). Ten of 67 evaluable patients achieved confirmed partial response, with an objective response rate (ORR) of 14.9% (95% confidence interval [CI], 8.3-24.0); the ORR was 33.3%, 14.0%, 0, and 25.0% at 4 mg, 8 mg, 12 mg, and 16 mg, respectively. Besides, the ORR in patients without and with EGFR T790M mutation was 20.5% and 7.4%, respectively. Moreover, 39 patients achieved stable disease across all doses, and the disease control rate was 73.1% (95% CI, 60.9-83.2). Median progression-free survival was 4.1 (95% CI, 2.9-5.3) months. Median duration of response and overall survival have not been reached. CONCLUSIONS: FCN-411 was well tolerated and demonstrated preliminary antitumor activity in patients with EGFR-mutated NSCLC after progression on EGFR-TKIs, especially in those without EGFR T790M mutation. The RP2D was defined as 8 mg once daily. Future studies are warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03420079.

A first-in-human, phase 1a dose-escalation study of the selective MEK1/2 inhibitor FCN-159 in patients with advanced NRAS-mutant melanoma.

BACKGROUND: A phase 1a first-in-human study evaluated the safety/tolerability, preliminary antitumour activity and pharmacokinetics of the oral MEK1/2 inhibitor FCN-159 in Chinese patients with advanced, NRAS-mutant melanoma. PATIENTS AND METHODS: Patients received a single FCN-159 dose at assigned levels, proceeding to continuous dosing (once daily [QD] for 28-day cycles) if no dose-limiting toxicities (DLTs) occurred within the next 3 days. Dose escalation was initiated after review of data for the previous dose level. The primary end-point was incidence of DLTs after the first dose. RESULTS: Thirty-three patients were enrolled across nine FCN-159 dose groups (0.2-15 mg QD). One DLT occurred: grade 3 folliculitis in the 15-mg group. There was one grade >3 treatment-emergent adverse event (TEAE), death of unknown aetiology (not FCN-159 related). The most common FCN-159-related TEAE was rash (36.4%), and the incidence of grade ≥3 FCN-159-related TEAEs was 15.2%. Antitumour activity at QD doses <6 mg was limited; therefore, efficacy data are presented only for doses ≥6 mg (n = 21). The objective response and clinical benefit rates were 19.0% (four partial responses) and 52.4%, respectively. Median (95% confidence interval) duration of response and progression-free survival were 4.8 months (2.8-not reached) and 3.8 months (1.8-5.6), respectively. FCN-159 exposure increased dose-proportionately; geometric mean terminal half-life was 29.9-56.9 h. CONCLUSIONS: FCN-159 was well tolerated and demonstrated promising antitumour activity at doses ≥6 mg QD in patients with advanced, NRAS-mutant melanoma. The recommended phase 2 dose was 12 mg QD. GOV IDENTIFIER: NCT03932253. https://clinicaltrials.gov/ct2/show/NCT03932253.

A phase 3, double-blind, randomized placebo-controlled efficacy and safety study of abiraterone acetate in chemotherapy-naïve patients with mCRPC in China, Malaysia, Thailand and Russia.

OBJECTIVE: This double-blind, placebo-controlled phase 3 study was designed to compare efficacy and safety of abiraterone acetate + prednisone (abiraterone) to prednisone alone in chemotherapy-naïve, asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer (mCRPC) patients from China, Malaysia, Thailand and Russia. METHODS: Adult chemotherapy-naïve patients with confirmed prostate adenocarcinoma, Eastern Cooperative Oncology Group (ECOG) performance status (PS) grade 0-1, ongoing androgen deprivation (serum testosterone <50 ng/dL) with prostate specific antigen (PSA) or radiographic progression were randomized to receive abiraterone acetate (1000 mg, QD) + prednisone (5 mg, BID) or placebo + prednisone (5 mg, BID), until disease progression, unacceptable toxicity or consent withdrawal. Primary endpoint was improvements in time to PSA progression (TTPP). RESULTS: Totally, 313 patients were randomized (abiraterone: n = 157; prednisone: n = 156); and baseline characteristics were balanced. At clinical cut-off (median follow-up time: 3.9 months), 80% patients received treatment (abiraterone: n = 138, prednisone: n = 112). Median time to PSA progression was not reached with abiraterone versus 3.8 months for prednisone, attaining 58% reduction in PSA progression risk (HR = 0.418; p < 0.0001). Abiraterone-treated patients had higher confirmed PSA response rate (50% vs. 21%; relative odds = 2.4; p < 0.0001) and were 5 times more likely to achieve radiographic response than prednisone-treated patients (22.9% vs. 4.8%, p = 0.0369). Median survival was not reached. Most common (≥10% abiraterone vs. prednisone-treated) adverse events: bone pain (7% vs. 14%), pain in extremity (6% vs. 12%), arthralgia (10% vs. 8%), back pain (7% vs. 11%), and hypertension (15% vs. 14%). CONCLUSION: Interim analysis confirmed favorable benefit-to-risk ratio of abiraterone in chemotherapy-naïve men with mCRPC, consistent with global study, thus supporting use of abiraterone in this patient population.