Recruiting
Phase 1
Phase 2

Mavrostobart & PD-1 Inhibitor

Sponsor:

Phanes Therapeutics

Code:

NCT05431270

Conditions

Non Small Cell Lung Cancer

Pancreatic Ductal Adenocarcinoma

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Mavrostobart (PT199)

Tislelizumab

Gemcitabine + nab-Paclitaxel

Docetaxel

Pemetrexed

Study Details

Brief summary:

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.

Conditions

Non Small Cell Lung Cancer

Pancreatic Ductal Adenocarcinoma

Study ID

NCT05431270

Start date

Aug 11, 2022

Status verified date

May, 2026

Completion date

Aug, 2028

Anticipated

Primary completion date

Dec, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Key Inclusion Criteria

1. 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, which may include a checkpoint inhibitor.

For Part D:
  • Cohort D1: a histologically or cytologically confirmed diagnosis of pancreatic ductal adenocarcinoma (PDAC), treatment naïve for advanced or metastatic disease, and eligible to receive standard of care treatment with gemcitabine plus nab-paclitaxel.
  • Cohort D2: 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. Patients have progressed under first-line (1L) SOC chemotherapy with or without ICI or later lines of therapy, or for which standard 1L therapy has proven to be ineffective, intolerable, or is considered inappropriate.
  • Cohort D3: a histologically or cytologically confirmed diagnosis of NSCLC without actionable genomic alterations (AGAs) such as EGFR or ALK mutations. Patients are treatment naïve and have no contra indication to receive carboplatin plus pemetrexed.
  • Cohort D4: a histologically or cytologically confirmed diagnosis of NSCLC without actionable genomic alterations (AGAs) such as EGFR or ALK mutations. Patients are treatment naïve and are eligible for 1L therapy with pembrolizumab and carboplatin plus pemetrexed.
3. In all Parts, should be able to provide a tumor tissue sample (archival or newly acquired biopsy) to be assessed for CD73 and other biomarkers (PD-L1), unless deemed by the Investigator to cause risk to the patient or per Investigator's discretion.
4. ECOG performance status of 0 or 1.
5. Adequate organ function confirmed at screening and within 72 hours of initiating treatment.

Key Exclusion Criteria

1. Women who are pregnant or lactating.
2. Women of child-bearing potential (WOCBP) who do not use adequate birth control.
3. Autoimmune disease requiring systemic treatment within the past twelve months. Active autoimmune disease or a history of autoimmune diseases that may relapse.
4. Condition requiring systemic treatment with either corticosteroids or other immunosuppressive medications within 14 days prior to study treatment.
5. Patients who have experienced Grade ≥ 3 immune-related events, such as (non-infectious) pneumonitis, interstitial lung disease, myocarditis.
6. Patients with untreated brain or central nervous system (CNS) metastases or brain/CNS metastases that have progressed.
7. Impaired cardiac function or significant diseases.
8. Patients who have ≥ Grade 3 neuropathy.
9. Patients who have received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation ≤ 2 weeks prior to starting study drug or who have not recovered from adverse events of prior therapy.
10. Patients who are currently receiving (last dose within 5 days from C1D1) treatment with therapeutic doses of warfarin sodium (Coumadin®) or any other coumarin-derivative anticoagulants.

Additional inclusion and exclusion criteria will apply.

Study Design

Enrollment

40 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Part A: Monotherapy Dose Escalation

A standard 3+3 dose escalation design will be employed, and 3 patients will be enrolled initially at each dose level. Mavrostobart (PT199) will be administered as a monotherapy.

experimental: Part B: Combination Therapy Dose Escalation

A standard 3+3 dose escalation design will be employed, and 3 patients will be enrolled initially at each dose level. Patients will be treated with Mavrostobart (PT199) in combination with a PD-1 inhibitor, tislelizumab.

experimental: Part C: Combination Therapy Dose Expansion

Two RDEs for Part C will be determined in Part B and will be further evaluated in two dose expansion cohorts. Patients will be treated with Mavrostobart (PT199) in combination with a PD-1 inhibitor, tislelizumab.

experimental: Part D: Chemotherapy Combination

The Chemotherapy Combination Therapy Dose Escalation and Expansion will investigate four cohorts, one in frontline PDAC, two in frontline NSCLC and one in second-line and later NSCLC patients. Patients will receive Mavrostobart (PT199) plus chemotherapy, with one cohort also receiving pembrolizumab.

Interventions

Mavrostobart (PT199)

Mavrostobart (PT199) is an anti-CD73 mAb with a differentiated mechanism of action.

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.

Gemcitabine + nab-Paclitaxel

Dosing is per Standard of Care.

Docetaxel

Dosing is per Standard of Care.

Pemetrexed

Dosing is per Standard of Care.

Gemcitabine

Dosing is per Standard of Care.

Carboplatin + Pemetrexed

Dosing is per Standard of Care.

Pembrolizumab + Carboplatin + Pemetrexed

Dosing is per Standard of Care.

Primary outcome measure

  • 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. ]

Central Contacts and Locations

Central contacts

Locations

Carolina BioOncology Institute

Recruiting

Huntersville, North Carolina, United States, 28078

Sarah Cannon Research Institute University of Oklahoma

Recruiting

Oklahoma City, Oklahoma, United States, 73104

SCRI Oncology Partners

Recruiting

Nashville, Tennessee, United States, 37203

The University of Texas MD Anderson Cancer Center

Recruiting

Houston, Texas, United States, 77030

NEXT Oncology

Recruiting

Fairfax, Virginia, United States, 22031

More Information

Sponsor

Phanes Therapeutics

Last update posted

May 19, 2026

Last verified

May, 2026

Keywords

  • Advanced
  • Metastatic
  • Refractory
  • Anti-CD73
  • Checkpoint immunotherapies
  • PD-1/PD-L1 inhibitors

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Phanes Therapeutics on 2026-05-19.