A Phase 1/2 interventional study of Retifanlimab and Gemcitabine in Soft Tissue Sarcoma, Sarcoma,Soft Tissue and Sarcoma, sponsored by Memorial Sloan Kettering Cancer Center. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-08.
Sponsored by Memorial Sloan Kettering Cancer Center · Phase 1/2, Interventional, and Treatment
This study is being done to find out whether the study drug Retifanlimab, a monoclonal antibody against the PD-1 protein, combined with gemcitabine and docetaxel, is a safe and effective treatment for your disease. Gemcitabine and docetaxel are chemotherapy drugs that are commonly used to treat soft tissue sarcoma. Retifanlimab is an experimental drug that boosts the immune system's ability to fight cancer cells. The study researchers think that Retifanlimab may help gemcitabine and docetaxel work better against soft tissue sarcoma that is either locally advanced or has spread beyond its original location (metastasized), and it cannot be removed with surgery (unresectable).
Diagnosis of metastatic or locally advanced and unresectable high-grade soft tissue sarcoma. Unresectable is defined as:
Presence of measurable disease per RECIST v1.1
Patients with chronic HBV (HBsAg-positive with undetectable or low HBV DNA and normal ALT, or HBsAg-negative with anti-HBc-positive serology) and HCV (completed curative antiviral treatment with HCV viral load below the limit of quantification) may be eligible
Table 2: Laboratory Parameters Required for Study Inclusion
Hematological Absolute neutrophil count (ANC): ≥ 1,500 /mcL Platelets: ≥ 75,000 / mcL Hemoglobin: ≥ 9g/dL or ≥ 5.6 mmol/L
Renal Serum creatinine: ≤ 1.5 X upper limit of normal (ULN) OR Measured or calculated creatinine clearance: ≥ 60 mL/min for patient with creatinine levels > 1.5 X institutional ULN (GFR can also be used in place of creatinine orCrCl)
Hepatic Serum total bilirubin: ≤ 1.5 X ULN OR Direct bilirubin ≤ ULN for patients with total bilirubin levels > 1.5 ULN except patients with Gilbert's disease (≤ 3x ULN) AST (SGOT) and ALT (SGPT): ≤ 2.5 X ULN OR ≤ 5 X ULN for patients with liver metastases
Exclusion Criteria:
Received any systemic therapy in the advanced or metastatic setting
Unstable or deteriorating cardiovascular disease within the previous 6 months, including:
Current use of immunosuppressive medication, EXCEPT for the following:
Evidence of clinically significant immunosuppression such as the following:
History or evidence of symptomatic autoimmune disease in past 2 years prior to enrollment.
Uncontrolled HIV infection, as defined by one or more of the following:
A safety run-in (dose level 0 in Table 1, below) will be performed and enroll 6 patients with advanced high-grade sarcoma who are treatment naïve. Cycle one will consist of gemcitabine plus docetaxel at the institution's standard dose and schedule: 900 mg/m2 of gemcitabine on days 1 and 8, and 75 mg/m2 of docetaxel on day 8. Intravenous Retifanlimab at a flat dose of 210 mg will be administered every 3 weeks starting on C2D1 for a total of two cycles (cycles 2 and 3). All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
If ≤ 1 patient out of 6 at dose level 0 has a dose-limiting toxicity during this safety run-in, then the dose de-escalation portion of the protocol will commence. Dose Level 1: Retifanlimab (Day 1) - 375 mg (flat dose) Gemcitabine (Days 1 and 8) - 900 mg/m2 Docetaxel (Day 8) - 75 mg/m2 All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
Dose Level -1: Retifanlimab (Day 1) - 375 mg (flat dose) Gemcitabine (Days 1 and 8) - 750 mg/m2 Docetaxel (Day 8) - 60 mg/m2 All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
Dose Level -2: Retifanlimab (Day 1) - 375 mg (flat dose) Gemcitabine (Days 1 and 8) - 675 mg/m2 Docetaxel (Day 8) - 50 mg/m2 All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
(UPS/MFS) After the RP2D is determined, 5 histology-specific cohorts (10 patients each), including UPS/MFS, LPS, LMS, vascular sarcoma, and other STS, will open for enrollment. Patients will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375 mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles), after which treatment with Retifanlimab will continue until unacceptable toxicity, disease progression, or the completion of 35 cycles (105 weeks) of Retifanlimab treatment. All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
After the RP2D is determined, 5 histology-specific cohorts (10 patients each), including UPS/MFS, LPS, LMS, vascular sarcoma, and other STS, will open for enrollment. Patients will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375 mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles), after which treatment with Retifanlimab will continue until unacceptable toxicity, disease progression, or the completion of 35 cycles (105 weeks) of Retifanlimab treatment. All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
After the RP2D is determined, 5 histology-specific cohorts (10 patients each), including UPS/MFS, LPS, LMS, vascular sarcoma, and other STS, will open for enrollment. Patients will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375 mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles), after which treatment with Retifanlimab will continue until unacceptable toxicity, disease progression, or the completion of 35 cycles (105 weeks) of Retifanlimab treatment. All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
After the RP2D is determined, 5 histology-specific cohorts (10 patients each), including UPS/MFS, LPS, LMS, vascular sarcoma, and other STS, will open for enrollment. Patients will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375 mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles), after which treatment with Retifanlimab will continue until unacceptable toxicity, disease progression, or the completion of 35 cycles (105 weeks) of Retifanlimab treatment. All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
After the RP2D is determined, 5 histology-specific cohorts (10 patients each), including UPS/MFS, LPS, LMS, vascular sarcoma, and other STS, will open for enrollment. Patients will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375 mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles), after which treatment with Retifanlimab will continue until unacceptable toxicity, disease progression, or the completion of 35 cycles (105 weeks) of Retifanlimab treatment. All visits are to be done +/-3 days of the scheduled timepoints.
Drug: Retifanlimab · Drug: Gemcitabine · Drug: Docetaxel
Participants will have advanced sarcoma who have progressed on prior treatment and have an immune-enriched/non-fibrotic TME
Drug: Retifanlimab
Phase I: Dose Level 1 - 375 mg (flat dose) Dose Level 0 - 210 mg (flat dose) Dose Level -1 - 375 mg (flat dose) Dose Level -2 - 375 mg (flat dose) Phase II: 375 mg (flat dose)
Also known as: INCMGA00012
Phase I: Dose Level 1 - 900 mg/m2 Dose Level 0 - 900 mg/m2 Dose Level -1 - 750 mg/m2 Dose Level -2 - 675 mg/m2 The dose level with ≤ 1 DLT seen per patients will be declared the RP2D. Phase II: Participants will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab ) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles),
Phase I: Dose Level 1 - 75 mg/m2 Dose Level 0 - 75 mg/m2 Dose Level -1 - 60 mg/m2 Dose Level -2 - 50 mg/m2 The dose level with ≤ 1 DLT seen per patients will be declared the RP2D. Phase II: Participants will be treated with the RP2D of gemcitabine/docetaxel (when administered in combination with Retifanlimab) for cycle 1, with Retifanlimab added on cycle 2 day 1 at a flat dose of 375mg. Gemcitabine/docetaxel will continue for 5 additional cycles (total of 6 cycles),
Phase II: proportion of patients that are progression-free at 24 weeks by RECIST v1.1
The primary objective of the phase II portion of this study is to determine the proportion of patients that are progression-free at 24 weeks by RECIST v1.1. Progressive disease is declared when there is an increase in sum of target disease ≥ 20%, stable disease when the change is \> -30% and ≤ 20%, partial response when there is a decrease in sum of target disease ≥ 30%, and complete response when all lesions have disappeared or all lesions have disappeared and all nodal disease is \< 10 mm each.
Time frame: 24 weeks
Plan to share: Yes — Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.
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