Population pharmacokinetics of imetelstat, a first-in-class oligonucleotide telomerase inhibitor.

Imetelstat is a novel, first-in-class, oligonucleotide telomerase inhibitor in development for the treatment of hematologic malignancies including lower-risk myelodysplastic syndromes and myelofibrosis. A nonlinear mixed-effects model was developed to characterize the population pharmacokinetics of imetelstat and identify and quantify covariates that contribute to its pharmacokinetic variability. The model was developed using plasma concentrations from 7 clinical studies including 424 patients with solid tumors or hematologic malignancies who received single-agent imetelstat via intravenous infusion at various dose levels (0.4-11.7 mg/kg) and schedules (every week to every 4 weeks). Covariate analysis included factors related to demographics, disease, laboratory results, renal and hepatic function, and antidrug antibodies. Imetelstat was described by a two-compartment, nonlinear disposition model with saturable binding/distribution and dose- and time-dependent elimination from the central compartment. Theory-based allometric scaling for body weight was included in disposition parameters. The final covariates included sex, time, malignancy, and dose on clearance; malignancy and sex on volume of the central compartment; and malignancy and spleen volume on concentration of target. Clearance in females was modestly lower, resulting in nonclinically relevant increases in predicted exposure relative to males. No effects on imetelstat pharmacokinetics were identified for mild-to-moderate hepatic or renal impairment, age, race, and antidrug antibody status. All model parameters were estimated with adequate precision (relative standard error < 29%). Visual predictive checks confirmed the capacity of the model to describe the data. The analysis supports the imetelstat body-weight-based dosing approach and lack of need for dose individualizations for imetelstat-treated patients.

Imetelstat in patients with lower-risk myelodysplastic syndromes who have relapsed or are refractory to erythropoiesis-stimulating agents (IMerge): a multinational, randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Unmet medical needs remain in patients with red blood cell transfusion-dependent (RBC-TD) lower-risk myelodysplastic syndromes (LR-MDS) who are not responding to or are ineligible for erythropoiesis-stimulating agents (ESAs). Imetelstat, a competitive telomerase inhibitor, showed promising results in a phase 2 trial. We aimed to compare the RBC transfusion independence (RBC-TI) rate with imetelstat versus placebo in patients with RBC-TD LR-MDS. METHODS: In phase 3 of IMerge, a double-blind, placebo-controlled trial conducted in 118 sites including university hospitals, cancer centres, and outpatient clinics in 17 countries, patients (aged ≥18 years) with ESA-relapsed, ESA-refractory, or ESA-ineligible LR-MDS (low or intermediate-1 risk disease as per International Prognostic Scoring System [IPSS] criteria) were randomly assigned via a computer-generated schedule (2:1) to receive imetelstat 7·5 mg/kg or placebo, administered as a 2-h intravenous infusion, every 4 weeks until disease progression, unacceptable toxic effects, or withdrawal of consent. Randomisation was stratified by previous RBC transfusion burden and IPSS risk group. Patients, investigators, and those analysing the data were masked to group assignment. The primary endpoint was 8-week RBC-TI, defined as the proportion of patients without RBC transfusions for at least 8 consecutive weeks starting on the day of randomisation until subsequent anti-cancer therapy, if any. Primary efficacy analyses were performed in the intention-to-treat population, and safety analyses were conducted in patients who received at least one dose of trial medication or placebo. This trial is registered with ClinicalTrials.gov (NCT02598661; substudy active and recruiting). FINDINGS: Between Sept 11, 2019, and Oct 13, 2021, 178 patients were enrolled and randomly assigned (118 to imetelstat and 60 to placebo). 111 (62%) were male and 67 (38%) were female. 91 (77%) of 118 patients had discontinued treatment by data cutoff in the imetelstat group versus 45 (75%) in the placebo group; a further one patient in the placebo group did not receive treatment. Median follow-up was 19·5 months (IQR 12·0-23·4) in the imetelstat group and 17·5 months (12·1-22·7) in the placebo group. In the imetelstat group, 47 (40% [95% CI 30·9-49·3]) patients had an RBC-TI of at least 8 weeks versus nine (15% [7·1-26·6]) in the placebo group (rate difference 25% [9·9 to 36·9]; p=0·0008). Overall, 107 (91%) of 118 patients receiving imetelstat and 28 (47%) of 59 patients receiving placebo had grade 3-4 treatment-emergent adverse events. The most common treatment-emergent grade 3-4 adverse events in patients taking imetelstat were neutropenia (80 [68%] patients who received imetelstat vs two [3%] who received placebo) and thrombocytopenia (73 [62%] vs five [8%]). No treatment-related deaths were reported. INTERPRETATION: Imetelstat offers a novel mechanism of action with durable transfusion independence (approximately 1 year) and disease-modifying activity for heavily transfused patients with LR-MDS who are not responding to or are ineligible for ESAs. FUNDING: Janssen Research & Development before April 18, 2019, and Geron Corporation thereafter.

Imetelstat in intermediate-2 or high-risk myelofibrosis refractory to JAK inhibitor: IMpactMF phase III study design.

Imetelstat, a first-in-class telomerase inhibitor, demonstrated meaningful clinical benefit including a robust symptom response rate and potential overall survival benefit in IMbark, a phase II study in intermediate-2 or high-risk myelofibrosis (MF) patients who have relapsed after or are refractory to JAK inhibitors. We describe the rationale and design for the phase III trial, IMpactMF (NCT04576156), an open-label evaluation of imetelstat versus best available therapy, excluding JAK inhibitors, in MF patients refractory to JAK inhibitor. Imetelstat 9.4 mg/kg is administered as an intravenous infusion every 21 days. Primary objective is to assess overall survival. Secondary objectives include symptom and spleen responses, progression-free survival, clinical response assessment, bone marrow fibrosis reduction, safety and pharmacokinetics. Biomarker, cytogenetics and mutation analyses will be performed.

Imetelstat is a new type of treatment being studied in patients with myelofibrosis (MF). Encouraging clinical benefits were seen in a phase II clinical trial of imetelstat in higher risk MF. This article discusses the ongoing phase III trial, called IMpactMF. IMpactMF is comparing imetelstat to best available therapy (BAT) in MF patients not responding to a specific type of treatment, a JAK inhibitor. Imetelstat is an intravenous infusion, given every 21 days. This study will determine if patients who receive imetelstat live longer than patients who are given BAT. It will also collect information on additional outcomes, including safety. Trial Registration Number: NCT04576156 (ClinicalTrials.gov).

Fedratinib in patients with myelofibrosis previously treated with ruxolitinib: An updated analysis of the JAKARTA2 study using stringent criteria for ruxolitinib failure.

Fedratinib is an oral, selective Janus kinase 2 (JAK2) inhibitor. The phase II JAKARTA2 study assessed fedratinib in patients with intermediate- or high-risk myelofibrosis (MF) who were resistant or intolerant to prior ruxolitinib per investigator assessment. Patients received fedratinib 400 mg/day in 28-day cycles. The JAKARTA2 outcomes were initially reported using a last-observation-carried forward (LOCF) analysis in a "Per Protocol" population. This updated analysis of JAKARTA2 employs intention-to-treat analysis principles without LOCF for all treated patients (ITT Population; N = 97), and for a patient subgroup who met more stringent definitions of prior ruxolitinib failure (Stringent Criteria Cohort; n = 79). Median duration of prior ruxolitinib exposure was 10.7 months. The primary endpoint was spleen volume response rate (SVRR; ≥35% spleen volume decrease from baseline to end of cycle 6 [EOC6]). The SVRR was 31% in the ITT Population and 30% in the Stringent Criteria Cohort. Median duration of spleen volume response was not reached. Symptom response rate (≥50% reduction from baseline to EOC6 in total symptom score [TSS] on the modified Myelofibrosis Symptom Assessment Form [MFSAF]) was 27%. Grade 3-4 anemia and thrombocytopenia rates were 38% and 22%, respectively. Patients with advanced MF substantially pretreated with ruxolitinib attained robust spleen responses and reduced symptom burden with fedratinib.

nab-Paclitaxel-Based Therapy in Underserved Patient Populations: The ABOUND.PS2 Study in Patients With NSCLC and a Performance Status of 2.

INTRODUCTION: The phase II ABOUND.PS2 study (NCT02289456) assessed safety/tolerability of a first-line modified nab-paclitaxel/carboplatin regimen for patients with advanced non-small cell lung cancer (NSCLC) and Eastern Cooperative Oncology Group (ECOG) performance status (PS) 2. METHODS: Chemotherapy-naive patients with stage IIIB/IV NSCLC and ECOG PS 2 received four cycles of nab-paclitaxel 100 mg/m2 days 1 and 8 plus carboplatin area under the curve 5 day 1 q3w (induction). Patients without progression received nab-paclitaxel monotherapy (100 mg/m2 days 1 and 8 q3w) until progression/unacceptable toxicity. Primary endpoint: percentage of patients discontinuing induction due to treatment-emergent adverse events (TEAEs). RESULTS: 11/40 treated patients (27.5%; 95% CI, 14.60-43.89) discontinued chemotherapy induction due to TEAEs; 16/40 (40.0%) continued nab-paclitaxel monotherapy. Median progression-free and overall survival were 4.4 (95% CI, 2.99-7.00) and 7.7 (95% CI, 4.93-13.17) months. Grade 3/4 TEAEs during induction included neutropenia (22.5%), anemia (17.5%), thrombocytopenia (5.0%), and peripheral neuropathy (2.5%). CONCLUSION: This nab-paclitaxel-based regimen was tolerable in patients with advanced NSCLC and ECOG PS 2, with efficacy comparable to historical chemotherapy data.

nab-Paclitaxel-Based Therapy in Underserved Patient Populations: The ABOUND.70+ Study in Elderly Patients With Advanced NSCLC.

The phase 4 ABOUND.70+ trial assessed the safety and efficacy of nab-paclitaxel/carboplatin continuously or with a 1-week break between cycles in elderly patients with advanced non-small cell lung cancer (NSCLC). Patients ≥70 years with locally advanced/metastatic NSCLC were randomized 1:1 to first-line nab-paclitaxel days 1, 8, 15 plus carboplatin day 1 of a 21-day cycle (21d) or the same nab-paclitaxel/carboplatin regimen with a 1-week break between cycles (21d + break; 28d). The primary endpoint was the percentage of patients with grade ≥ 2 peripheral neuropathy (PN) or grade ≥ 3 myelosuppression. Other key endpoints included progression-free survival (PFS), overall survival (OS), and overall response rate (ORR). A total of 143 patients were randomized (71 to 21d, 72 to 21d + break). The percentage of patients with grade ≥ 2 PN or grade ≥ 3 myelosuppression was similar between the 21d and 21d + break arms (76.5 and 77.1%; P = 0.9258). Treatment exposure was lower in the 21d arm compared with the 21d + break arm. Median OS was 15.2 and 16.2 months [hazard ratio (HR) 0.72, 95% CI 0.44-1.19; P = 0.1966], median PFS was 3.6 and 7.0 months (HR 0.48, 95% CI 0.30-0.76; P < 0.0019), and ORR was 23.9 and 40.3% (risk ratio 1.68, 95% CI 1.02-2.78; P = 0.0376) in the 21d and 21d + break arms, respectively. In summary, the 1-week break between treatment cycles significantly improved PFS and ORR but did not significantly reduce the percentage of grade ≥ 2 PN or grade ≥ 3 myelosuppression. Overall, the findings support the results of prior subset analyses on the safety and efficacy of first-line nab-paclitaxel/carboplatin in elderly patients with advanced NSCLC.