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Evaluating TL-895 for treating Myelofibrosis and Indolent Systemic Mastocytosis

A Phase 2 Multicenter Study of TL-895 in Subjects With Relapsed/Refractory Myelofibrosis, Janus Kinase Inhibitor Intolerant Myelofibrosis, Janus Kinase Inhibitor Treatment Ineligible Myelofibrosis, or Indolent Systemic Mastocytosis

Phase 2 Interventional Telios Pharma, Inc. · NCT04655118

This study is testing a new pill called TL-895 to see if it helps people with Myelofibrosis or Indolent Systemic Mastocytosis who haven't had success with other treatments.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment121 (estimated)
Ages18 Years and up
SexAll
SponsorTelios Pharma, Inc. Industry-sponsored
Drugs / interventionsAvapritinib, bezuclastinib, elenestinib
Locations52 sites (Aurora, Colorado and 51 other locations)
Trial IDNCT04655118 on ClinicalTrials.gov

What this trial studies

This clinical trial assesses the efficacy of TL-895, an oral and selective irreversible tyrosine kinase inhibitor, in patients diagnosed with Myelofibrosis or Indolent Systemic Mastocytosis. Participants must have relapsed or refractory Myelofibrosis, be intolerant, or ineligible for JAK inhibitor treatment, or have a confirmed diagnosis of Indolent Systemic Mastocytosis. The study includes multiple cohorts to evaluate the drug's effectiveness and safety compared to a placebo.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with confirmed Myelofibrosis or Indolent Systemic Mastocytosis who meet specific eligibility criteria.

Not a fit: Patients who have previously received treatment with BTK or BMX inhibitors or JAK inhibitors within the specified time frame may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with Myelofibrosis or Indolent Systemic Mastocytosis who have limited treatment alternatives.

How similar studies have performed: While this approach is novel in the context of TL-895, similar studies evaluating tyrosine kinase inhibitors have shown promise in treating related conditions.

Eligibility criteria

Show full inclusion / exclusion criteria 
Cohorts 1-3

Key Inclusion Criteria:

* Adults ≥18 years of age
* Confirmed diagnosis of PMF, post-PV MF, or post-ET MF, as assessed by treating physician according to the World Health Organization (WHO) criteria
* Eastern Cooperative Oncology Group (ECOG) performance status of ≤2
* Adequate hematologic, hepatic, and renal functions
* MF symptoms as defined by having at least 2 symptoms with an average baseline (Day -7 to Day -1) score of at least 1 for each of the 2 symptoms per MFSAF v4.0
* Cohort 3 only: Ineligibility for JAKi treatment with a platelet count of ≥ 25 and \< 50 x 10\^9/L

Key Exclusion Criteria:

* Prior treatment with any BTK or BMX inhibitors
* Prior treatment with JAKi within 28 days prior to study treatment
* Prior splenectomy or splenic irradiation within 24 weeks prior to first dose of study treatment

Cohort 5

Key Inclusion Criteria:

* Adults ≥18 years of age
* Confirmed diagnosis of ISM as defined by WHO diagnostic criteria based on review of bone marrow biopsy pathology report results
* Subject must have moderate-to-severe symptoms

Key Exclusion Criteria:

* Prior treatment with any BTK or BMX inhibitors
* Prior treatment with Avapritinib, bezuclastinib, or BLU-263/elenestinib
* Diagnosis with another myeloproliferative disorder

Where this trial is running

Aurora, Colorado and 51 other locations

+2 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions MyelofibrosisIndolent Systemic Mastocytosis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.