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Prostate CancerPhase 2POSTPONENCT07226713

Pacritinib in Participants With Metastatic Castrate-Resistant Prostate Cancer That Progressed on or After Prior Treatment With Androgen Receptor Signaling Inhibitors

A Phase 2 study testing Pacritinib in people with Prostate Cancer, run by Medical College of Wisconsin at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

This is a single-arm, open-label phase 2 study to evaluate the role of pacritinib for patients with metastatic castrate-resistant prostate cancer that have progressed on ARSI. Patients will receive pacritinib 200 mg twice daily. Read more about this study

Who is it for?
Ages 18 years and older, men only
Conditions the study is for
Prostate Cancer
What is being tested?
Pacritinib
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
32 participants
Where
1 siteUnited States
Study dates
3 Sep 2026to 1 Mar 2031
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Men only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • To be eligible for screening:
  • Patients aged ≥ 18 years.
  • Histologically or cytologically confirmed prostate adenocarcinoma.
  • Have current evidence of metastatic disease documented by either bone scan, CT/MRI and/or PSMA PET scan
  • Have disease that progressed while receiving androgen deprivation therapy (ADT) (or post bilateral orchiectomy) and during or after treatment with at least one androgen receptor signaling inhibitor (ARSI) (e.g., abiraterone acetate, enzalutamide, apalutamide, darolutamide) for metastatic hormone-sensitive prostate cancer (HSPC) (mHSPC or nmHSPC) or mCRPC.
  • Note: Participants may have received abiraterone acetate and docetaxel or darolutamide and docetaxel for HSPC. However, participants must have received no more than 6 cycles of docetaxel and had no radiographic disease progression while receiving docetaxel. Disease progression could be prostate-specific antigen (PSA) based or radiographic progression per Prostate Cancer Working Group 3 (PCWG3) guidelines.
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  • Screening serum testosterone < 50 ng/dL.
  • Eastern Cooperative Oncology Group (ECOG), Performance Status grade 0-1 or Karnofsky Performance Status ≥ 70
  • No prior janus kinase2 (JAK2) inhibitor treatment.
  • Left ventricular cardiac ejection fraction of ≥ 50% by echocardiogram or multigated acquisition (MUGA) scan.
  • Adequate organ function as defined by the following laboratory values at screening:
  • Serum aspartate transaminase (AST), serum glutamic oxaloacetic transaminase (SGOT), serum alanine transaminase (ALT) and serum glutamic pyruvic transaminase (SGPT) < 2.5 x upper limit of normal (ULN).
  • Total serum bilirubin ≤ 1.5 x ULN. In subjects with Gilbert's syndrome, if total bilirubin is >1.5 × ULN, measure direct and indirect bilirubin and if direct bilirubin is ≤ 1.5 × ULN, the subject may be eligible).
  • Serum potassium ≥ 3.5 mmol/L. Supplementation and re-screening is allowed.
  • Estimated glomerular filtration rate (GFR) > 45 ml/min using the Cockroft-Gault equation.
  • Platelets ≥ 100,000/mL independent of transfusion and/or growth factors within three months
  • Hemoglobin ≥ 9.0 g/dL independent of transfusion and/or growth factors within three months
  • Absolute neutrophil count ≥ 500/µL.
  • Serum albumin ≥ 3.0 g/dL.
  • Adequate coagulation defined by prothrombin time (PT)/international normalized ratio (INR) and PTT ≤ 1.5 ULN.
  • Male patients, even if surgically sterilized (i.e., status post-vasectomy), must agree to one of the following:
  • Practice effective barrier contraception and another effective method of birth control if he is having sex with a woman of childbearing potential during the entire study period and through 30 calendar days after the last dose of study agent
  • Ability to understand a written informed consent document, and the willingness to sign it.
  • To be eligible for treatment:
  • Patients must meet all screening criteria described above.
  • Patients must provide tumor tissue from a fresh core or excisional biopsy from soft tissue not previously irradiated. Samples from tumors progressing at a prior site of radiation are allowed. Participants with bone-only or bone-predominant disease may provide a bone biopsy sample. A tumor sample must be obtained within 30 days of treatment.
  • STAT5 activation levels need to be high, with positive STATA5 activation status defined as detectable nuclear localized Stat5 in >5% of cancer cells from tissue obtained within 30 days of treatment.

Who cannot join

  • Patient does not have positive STAT5 activation status in PC core biopsies.
  • Previously treated with pacritinib.
  • Use of investigational agents within 28 days prior to randomization.
  • Use of other prohibited medications within seven days prior to Cycle 1, Day 1 or 5x half-life of the drug, whichever is longer.
  • Systemic treatment with a strong CYP3A4 inhibitor or inducer within 14 days prior to the start of treatment.
  • Uncontrolled hypertension.
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  • Baseline severe hepatic impairment (Child-Pugh Class B \& C).
  • An intercurrent illness that is not controlled, such as active infection, psychiatric illness, or social situations that would limit compliance with study requirements.
  • Any chronic medical condition requiring a higher dose of corticosteroid than an equivalent of 10 mg prednisone/prednisolone per day.
  • Significant recent bleeding history, as defined as National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v5.0 Grade ≥ 2 within three months prior to start of treatment, unless precipitated by an inciting event (e.g., surgery, trauma, or injury).
  • Systemic treatment with medications that increase the risk of bleeding, including anticoagulants (warfarin, direct oral anticoagulant, etc.), antiplatelet agents (except for aspirin dosages of ≤ 100 mg/day), anti-vascular endothelial growth factor (anti-VEGF) agents, and daily use of COX-1 inhibiting nonsteroidal anti-inflammatory agents (NSAIDs) within 14 days prior to the start of treatment.
  • Systemic treatment with medications that can prolong the QT interval within 14 days prior to the start of treatment. Shorter washout periods may be permitted with the approval of the PI, provided that the washout period is at least five half-lives of the drug prior to the start of treatment.
  • Any history of CTCAE v5.0 Grade ≥ 2 cardiac conditions within six months before treatment Day 1. Patients with asymptomatic Grade 2 non-dysrhythmia cardiovascular conditions may be considered for inclusion, with the approval of the principal investigator, if stable and unlikely to affect patient safety.
  • QT corrected for heart rate by Fridericia's cube root formula (QTcF) prolongation > 450 ms or other factors that increase the risk for QT interval prolongation (e.g., heart failure, hypokalemia [defined as serum potassium < 3.0 mEq/L that is persistent and refractory to correction]), or history of long QT interval syndrome.
  • New York Heart Association Class II, III, or IV congestive heart failure.
  • Any active gastrointestinal or metabolic condition that could interfere with absorption of oral medication.
  • Active or uncontrolled inflammatory or chronic functional bowel disorder, such as Crohn's disease, inflammatory bowel disease, chronic diarrhea, or chronic constipation.
  • Other malignancy within three years prior to the start of treatment, other than curatively treated basal cell or squamous cell skin
  • Uncontrolled intercurrent illness, including, but not limited to, ongoing active infection, psychiatric illness, or social situation that, in the judgment of the treating physician, would limit compliance with study requirements.
  • Known seropositivity for human immunodeficiency virus.
  • Known active hepatitis A, B, or C virus infection.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Medical College of Wisconsin Cancer Center Clinical Trials Office contact

866-680-0505 ext. 8900

cccto@mcw.edu

United States1 site, 1 recruiting
  • Froedtert & the Medical College of Wisconsin

    Milwaukee, Wisconsin, 53226

    Deepak Kilari, MD, 414-805-4600, dkilari@mcw.edu

    Deepak Kilari, MD

    Recruiting

Other trials in United States

About this study

Official title: A Single-Arm, Open-label, Phase II Study Evaluating Pacritinib in Participants With Metastatic Castrate-Resistant Prostate Cancer That Progressed on or After Prior Treatment With Androgen Receptor Signaling Inhibitors - (POSTPONE)

This is a single-arm, open-label phase 2 study to evaluate the role of pacritinib for patients with metastatic castrate-resistant prostate cancer that have progressed on ARSI. Patients will receive pacritinib 200 mg twice daily. To be eligible, patients must have a biopsy of a metastatic site within 30 days of treatment that demonstrates positive STAT5 activation status

Conditions
Prostate Cancer
Being tested
Pacritinib
Medical subject headings
Prostatic Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PacritinibDrug

    Also called SB1518

    Pacritinib is an oral drug which will be taken daily at a dose of 200 mg twice a day (BID).

Study groups in NCT07226713
Study groupRoleWhat they receive
PacritinibExperimentalPacritinib is an oral drug.
Receives: Drug: Pacritinib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Progression-free Survival

    Six-month radiographic progression-free survival is defined as the probability that a given subject will be alive and free from radiographic progression per Prostate Cancer Working Group 3 guidelines at 24 weeks.

    Measured: Six months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Nov 2025
  2. Study start3 Sep 2026
  3. Primary completion1 Mar 2029 (estimated)
  4. Study completion1 Mar 2031 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
32 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07226713
Sponsor's protocol ID
PRO00059128
Acronym
POSTPONE
Status last verified
Sep 2026
First submitted
6 Nov 2025
Last updated
9 Sep 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Pacritinib in people with Prostate Cancer, run by Medical College of Wisconsin at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 27 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 9 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Medical College of Wisconsin Cancer Center Clinical Trials Office (866-680-0505 ext. 8900, cccto@mcw.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Progression-free Survival (time frame: Six months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Sep 2026.

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