A Study to Evaluate the Safety, Pharmacokinetics, Pharmacodynamics and Clinical Activity of Imetelstat in Combination With Ruxolitinib in Participants With Myelofibrosis

An Open Label, Phase 1/1b Study to Evaluate the Safety, Pharmacokinetics, Pharmacodynamics and Clinical Activity of Imetelstat in Combination With Ruxolitinib in Patients With Myelofibrosis

The purpose of the study is to identify the recommended Part 2 dose (R2PD) of imetelstat sodium in combination with ruxolitinib in participants with myelofibrosis (MF) in Part 1, and to evaluate the safety and preliminary clinical activity of the R2PD of imetelstat sodium in combination with ruxolitinib in participants with MF in Part 2.

Study Overview

• Status: Recruiting
• Conditions: Myelofibrosis
• Intervention / Treatment: Drug: Imetelstat sodium; Drug: Ruxolitinib

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Judy Ho; Phone Number: 650-473-7793; Email: myf1001-info@geron.com
• Study Contact Backup: Name: Michelle Mudge-Riley, DO; Phone Number: 650-473-7793; Email: myf1001-info@geron.com

Study Locations

• United States
  • California
    • Duarte, California, United States, 91010
      • Recruiting
      • City of Hope
    • Irvine, California, United States, 92618
      • Recruiting
      • City of Hope
  • Florida
    • Coral Gables, Florida, United States, 33146
      • Recruiting
      • University of Miami
    • Tampa, Florida, United States, 33612
      • Recruiting
      • H. Lee Moffitt Cancer Center and Research Institute, Inc.
  • New York
    • New York, New York, United States, 10029
      • Recruiting
      • Icahn School of Medicine at Mount Sinai
  • Texas
    • Denison, Texas, United States, 75020
      • Withdrawn
      • Texas Oncology
    • Tyler, Texas, United States, 75702
      • Withdrawn
      • Texas Oncology
  • Washington
    • Seattle, Washington, United States, 98109
      • Recruiting
      • Fred Hutchinson Cancer Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of primary myelofibrosis (PMF) according to the revised World Health Organization (WHO) criteria or post-essential thrombocythemia-MF or post-polycythemia vera according to the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) criteria.
• Dynamic International Prognostic Scoring System (DIPSS) intermediate-1, intermediate-2 or high-risk MF.

• Candidate for ruxolitinib treatment:

  • Part 1 participants: On ruxolitinib treatment for at least 12 weeks with at least 4 consecutive weeks immediately prior to enrollment at a stable dose.
  • Part 2 participants: Candidate for ruxolitinib treatment as assessed by the investigator and has not previously been treated with a JAK inhibitor (Cohort A) OR currently receiving ruxolitinib per standard of care for at least 12 weeks with at least 4 consecutive weeks at a stable dose prior to enrollment (Cohort B). Note that the study will no longer recruit participants into Cohort A.

• Active symptoms of MF on the MFSAF v4.0 demonstrated by:

  • Part 1 participants only: At least 2 symptoms with a score ≥ 1
  • Part 2 participants only: At least 2 symptoms with a score of ≥ 3, or a total score of at least 10.
• Ineligible for or unwilling to undergo hematopoietic stem cell transplant at time of study entry.
• Hematology laboratory test values within protocol defined limits.
• Biochemical laboratory test values within protocol defined limits.
• Eastern Cooperative Oncology Group Performance Status score of 0, 1, or 2.
• Participants should follow protocol defined contraceptives procedures.
• A woman of childbearing potential must have a negative serum or urine pregnancy test at screening.

Exclusion Criteria:

• Peripheral blood blast count of ≥10% or bone marrow blast count of ≥10%.
• Prior treatment with JAK inhibitor (except for participants being dosed optimized on ruxolitinib treatment prior to screening and enrollment in part 1 or Part 2 Cohort B).
• Known allergies, hypersensitivity, or intolerance to imetelstat or ruxolitinib or excipients.
• Prior treatment with imetelstat.
• Major surgery within 28 days prior to enrollment.
• Any investigational drug regardless of class or mechanism of action, hydroxyurea, chemotherapy, (except for ruxolitinib for participants being dose optimized prior to enrollment), immunomodulatory or immunosuppressive therapy, corticosteroids >30 mg/day prednisone or equivalent ≤14 days prior to enrollment.
• Prior history of hematopoietic stem cell transplant.

• Diagnosis or treatment for malignancy other than MF, except:

  • Malignancy treated with curative intent and with no known active disease present for ≥3 years before enrollment.
  • Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease.
  • Adequately treated cervical carcinoma in situ without evidence of disease.
• Clinically significant cardiovascular disease.
• Known history of human immunodeficiency virus (HIV) or any uncontrolled active systemic infection requiring IV antibiotics.
• Active systemic hepatitis infection requiring treatment or any known acute or chronic liver disease unless related to MF. Carriers of hepatitis virus are permitted to enter the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part 1: Imetelstat sodium + Ruxolitinib; Participants who have received ruxolitinib orally (PO) as part of standard of care (SOC) for at least 12 weeks prior to Screening will be enrolled. After enrollment, participants will initiate imetelstat sodium therapy. Dose levels of imetelstat sodium may include 4.7, 6, 7.5, 9.4 mg/kg, until a RP2D is established.	Drug: Imetelstat sodium; Imetelstat sodium will be administered as intravenous (IV) every 28 days.; Other Names: GRN163L; Drug: Ruxolitinib; Ruxolitinib will be administered, orally (PO), twice daily (BID) in cohort B as the standard of care per local prescribing guidelines.
Experimental: Part 2: Imetelstat sodium + Ruxolitinib; Cohort A: Janus Kinase (JAK) inhibitor naive participants will receive initial treatment with ruxolitinib on study for at least 12 weeks, including 4 consecutive weeks at a stable dose, prior to the addition of imetelstat sodium. Participants can begin imetelstat sodium treatment after sponsor review and approval and meet the following requirements: platelet value is ≥75 x 10^9/L for two consecutive measurements, at least 1 week apart, and the participant does not meet criteria for dose delay. Note that the study will no longer recruit participants into Cohort A. Cohort B: Participants will receive treatment with ruxolitinib for 12 weeks with at least 4 consecutive weeks at a stable dose prior to enrollment and will start combination treatment with imetelstat on study.	Drug: Imetelstat sodium; Imetelstat sodium will be administered as intravenous (IV) every 28 days.; Other Names: GRN163L; Drug: Ruxolitinib; Ruxolitinib will be administered, orally (PO), twice daily (BID) in cohort B as the standard of care per local prescribing guidelines.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1: Incidence, Type, and Severity of Adverse Events, Including Dose-limiting Toxicity (DLT) During the DLT Observation Period and/or Study Treatment		28 days after first dose
Part 2: Number of Participants With Treatment-emergent Adverse Event (AE)	Safety will be assessed based on incidence and severity (according to Common Terminology Criteria for Adverse Events) of treatment emergent adverse events from the first dose of study treatment until 30 days after completion of treatment.	First dose of study treatment until 30 days after the last dose of study treatment (up to approximately 5 years)
Part 2: Symptom Response Rate at Week 24	Symptom response rate is defined as percentage of participants with >=50% reduction in the Total Symptom Score (TSS) measured by the Myelofibrosis Symptom Assessment Form (MFSAF) v4.0 e-diary at 24 week compared to baseline.	Week 24

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1: Pharmacokinetic Profile of Ruxolitinib (Maximum Observed Plasma Concentration [Cmax]		From first dose of Ruxolitinib treatment up to approximately 5 years
Part 1: Pharmacokinetic Profile of Ruxolitinib Time to Reach Maximum Plasma Concentration [Tmax])		From first dose of imetelstat treatment up to approximately 5 years
Part 1 and Part 2: Pharmacokinetic Profile of Imetelstat Sodium Maximum Observed Plasma Concentration [Cmax]		From first dose of imetelstat treatment up to approximately 5 years
Part 1 and Part 2: Pharmacokinetic Profile of Imetelstat Time to Reach Maximum Plasma Concentration [Tmax])		From first dose of imetelstat treatment up to approximately 5 years
Part 1 and Part 2: Percentage of Participants with Anti-imetelstat Antibodies		From first dose of imetelstat treatment up to approximately 5 years
Part 1: Symptom Response at Week 24	Symptom response rate is defined as percentage of participants with >50% reduction in the TSS measured by the MFSAF v4.0 e-diary at 24 week compared to baseline.	Baseline, Week 24
Part 1 and Part 2: Absolute Change From Baseline in TSS at Week 24	Absolute change is defined as change in total symptom score from baseline to week 24 as measured by the MFSAF v4.0 e-diary.	Baseline, Week 24
Part 1 and Part 2: Average Absolute Change in TSS Over 24 weeks	Average absolute change in TSS is defined as change in the average of absolute change in total symptom score from week 1(baseline) to week 24 as measured by the MFSAF v4.0 e-diary.	Baseline, Week 24
Part 1 and Part 2: Spleen Response at Week 24	Spleen response is the proportion of participants who achieve a reduction in spleen volume of ≥35% from baseline confirmed by magnetic resonance imaging (MRI) or computed tomography (CT).	Week 24
Part 1 and Part 2: Progression Free Survival (PFS)	The time interval from start of study treatment date to the first date of disease progression or death from any cause, whichever occurs first.	From start of study treatment date to the disease progression or death (up to approximately 5 years)
Part 1 and Part 2: Percentage of Participants With Complete Remission (CR), Partial Remission (PR), Clinical Improvement (CI) Per the Modified 2013 International Working Group - Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) Criteria.		From first dose to end of the treatment (up to approximately 5 years)
Part 1 and Part 2: Time to Response	Time to response was defined as the duration from first dose of study treatment to the earliest date that a response is first documented. The response CI/CR/PR was assessed by IWG-MRT criteria.	From first dose of study treatment to the earliest date that a response was first documented (Up to approximately 5 years)
Part 1 and Part 2: Duration of Response (DOR) Per IWG-MRT Criteria	DOR measured from time of initial response (CR/PR/CI) until documented PD or death whichever occurs first.	From time of initial response to PD or death whichever occurs first (up to approximately 5 years)
Part 1 and Part 2: Reduction of Bone Marrow Fibrosis	Reduction of bone marrow fibrosis is defined as the percentage of participants with a post-baseline bone marrow fibrosis degree smaller than the baseline fibrosis degree prior to start of subsequent anticancer therapy.	From first dose to end of the treatment (up to approximately 5 years)
Part 1 and Part 2: Time to Progression to Acute Myeloid Leukemia (AML)	Time to progression to AML, defined as the time interval from the start of study treatment date to the first date of documented progression to AML or death from any cause, whichever occurs first.	From first dose to end of the treatment (up to approximately 5 years)

Collaborators and Investigators

• Sponsor: Geron Corporation
• Investigators: Study Director: Michelle Mudge-Riley, DO, Geron Corporation

Study record dates

Study Major Dates

• Study Start (Actual): May 4, 2022
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): August 1, 2028

Study Registration Dates

• First Submitted: May 5, 2022
• First Submitted That Met QC Criteria: May 10, 2022
• First Posted (Actual): May 12, 2022

Study Record Updates

• Last Update Posted (Estimated): January 6, 2026
• Last Update Submitted That Met QC Criteria: December 31, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Hematologic Diseases; Bone Marrow Diseases; Myeloproliferative Disorders; Hemic and Lymphatic Diseases; Primary Myelofibrosis; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Protein Kinase Inhibitors; ruxolitinib; imetelstat; GRN163L peptide
• Other Study ID Numbers: MYF1001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No