NCT05431270 · Phanes Therapeutics
Dose Escalation/Expansion Study of Mavrostobart (PT199), an Anti-CD73 MAb, Administered Alone and in Combination with a PD-1 Inhibitor or Chemotherapy (the MORNINGSTAR Study)
What this study is about
This is a first-in-human, Phase 1/2, where both patients and doctors know the treatment given, study designed to evaluate the safety, tolerability, how the drug moves through the body, how the drug affects the body, and preliminary effectiveness of Mavrostobart (PT199) alone and in combination with a PD-1 inhibitor or chemotherapy.
View original scientific description
This is a first-in-human, Phase 1/2, open-label, study designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of Mavrostobart (PT199) alone and in combination with a PD-1 inhibitor or chemotherapy.
Interventions
DRUG
Mavrostobart (PT199)
Mavrostobart (PT199) is an anti-CD73 mAb with a differentiated mechanism of action.
DRUG
Tislelizumab
Anti-PD-1 monoclonal antibody 200 mg Q3W, inhibits the lymphocytes PD-1 receptors, blocking the ligands that would deactivate it and prevent an immune response.
DRUG
Gemcitabine + nab-Paclitaxel
Dosing is per Standard of Care.
DRUG
Docetaxel
Dosing is per Standard of Care.
DRUG
Pemetrexed
Dosing is per Standard of Care.
DRUG
Gemcitabine
Dosing is per Standard of Care.
DRUG
Carboplatin + Pemetrexed
Dosing is per Standard of Care.
DRUG
Pembrolizumab + Carboplatin + Pemetrexed
Dosing is per Standard of Care.
Primary outcome measures
To determine the maximum tolerated dose (MTD), if reached.
Time frame: Start of the study drug till 90 days after last dose.
Recommended Phase 2 Dose of Mavrostobart (PT199) as a single agent and/or in combination with a PD-1 inhibitor.
Time frame: Start of the study drug till 90 days after last dose.
Dose Limiting Toxicity (DLT).
Time frame: Time Frame: Start of the study drug till 90 days after last dose.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- At least one measurable lesion as defined by RECIST V1.1 criteria for solid tumors. 2. For Part A: a histologically or cytologically confirmed unresectable advanced or metastatic solid tumors previously treated with therapies, or for which treatment is not available or not tolerated. For Part B: A histologically or cytologically confirmed diagnosis of NSCLC without actionable genomic alterations (AGAs) such as EGFR or ALK mutations and radiological documentation of disease progression on prior treatments, which may include a checkpoint inhibitor, or patients diagnosed with metastatic and/or advanced (m/a) PDAC who have disease progression after previously treated with therapies, or for which treatment is not available or not tolerated. For Part C: A histologically or cytologically confirmed diagnosis of NSCLC without actionable genomic alterations such as EGFR or ALK mutations and radiological documentation of disease progression on prior treatments,
Where
- Huntersville, North Carolina
- Oklahoma City, Oklahoma
- Nashville, Tennessee
- Houston, Texas
- Webster, Texas
- Fairfax, Virginia
Collaborators
BeiGene
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 19, 2026 · Source of record for eligibility and locations