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AzTrials

Cervical CancerPhase 1/2NCT03495882

A Study of Zalifrelimab and Balstilimab for Treatment of Participants With Metastatic or Locally Advanced Solid Tumors, and Expansion Into Select Solid Tumors (Cervical)

A Phase 1/2 study testing Zalifrelimab and Balstilimab in people with Cervical Cancer, run by Agenus Inc. at 47 sites in 9 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

This is a Phase 1/2, open-label study of zalifrelimab (AGEN1884) in combination with balstilimab (AGEN2034) in participants with locally advanced, recurrent and/or metastatic solid tumors including cervical cancer. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Cervical Cancer
What is being tested?
Zalifrelimab and Balstilimab
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
175 participants
Where
47 sitesin 9 countries
Study dates
18 Dec 2017to 15 Jul 2022
Phase
Phase 1/2
Are there results?
Yes, posted in the registrySummary in the doctors' view

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
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • To be eligible for participation in this trial the participant must:
  • Voluntarily agree to participate by giving written informed consent (participation in pharmacogenomics testing is optional).
  • Be ≥18 years of age.
  • Diagnosis:
  • Phase 1: Male or female having a histologically or cytologically confirmed diagnosis of a locally advanced, recurrent, and/or metastatic solid tumor for which no standard therapy is available or standard therapy has failed.
  • Phase 2:
Show all 26Show fewer
  • Female having (1) a histologically or cytologically confirmed diagnosis of squamous cell carcinoma, adenosquamous carcinoma, or adenocarcinoma of the cervix, and (2) locally advanced, recurrent, and/or metastatic disease at the time of enrollment. Histologic confirmation of the original primary tumor is required via pathology report. Note: The following cervical tumors are not eligible: minimal deviation/adenoma malignum, gastric type adenocarcinoma, clear cell carcinoma, and mesonephric carcinoma.
  • Has cervical cancer and has relapsed after a platinum-based treatment (first line) regimen for locally advanced, recurrent, and/or metastatic disease. Note: Participants who only received platinum-based chemotherapy concurrently with primary radiation (for example, weekly cisplatin) or adjuvant chemotherapy following completion of radiation therapy (for example, paclitaxel and carboplatin for ≤4 cycles) and progressed within 6 months after treatment completion will be eligible as this systemic therapy will be considered first line.
  • Measurable Disease:
  • Phase 1: Have objective evidence of disease; the presence of measurable disease is not required.
  • Phase 2: Have measurable disease on imaging based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Note: Participants must have at least one "target lesion" to be used to assess response, as defined by RECIST version 1.1. Tumors within a previously irradiated field will be designated as "non-target" lesions unless progression is documented, or a biopsy is obtained to confirm persistence at least 90 days following completion of radiation therapy. Note: Measurable disease by RECIST 1.1 must be confirmed by independent central radiologic review prior to first dose. Participants without centrally confirmed measurable disease at baseline will not be eligible for this trial.
  • Have a life expectancy of at least 3 months and an Eastern Cooperative Oncology Group performance status of 0 or 1.
  • Have adequate organ function as indicated by the following laboratory values:
  • Adequate hematological function defined by absolute neutrophil count ≥1.5 x 10^9/liter (L), platelet count ≥100 x 10^9/L, and hemoglobin ≥8 grams/deciliter (without transfusions within 1 week of first dose).
  • Adequate hepatic function based on a total bilirubin level <1.5 x the institutional upper limit of normal (IULN), aspartate aminotransferase level ≤2.5 x IULN, alanine aminotransferase level ≤2.5 x IULN, and alkaline phosphatase ≤2.5 IULN.
  • Adequate renal function defined as creatinine ≤1.5 x IULN or calculated creatinine clearance ≥50 milliliters/minute for participants with creatinine levels >1.5 x IULN (if no local guideline is available, creatinine clearance should be calculated using the Cockcroft-Gault Method).
  • Adequate coagulation defined by international normalized ratio or prothrombin time ≤1.5 x IULN (unless the participant is receiving anticoagulant therapy); and activated partial thromboplastin time ≤1.5 x IULN (unless the participant is receiving anticoagulant therapy).
  • Other than the cancer for which the participant is enrolled, have no history of prior malignancy, with the exception of basal cell carcinoma of the skin, superficial bladder cancer, squamous-cell carcinoma of the skin, or has undergone potentially curative therapy with no evidence of that disease recurrence for 5 years since initiation of that therapy. Note: In Phase 2, the history and time requirement for no evidence of disease for 5 years does not apply to the cancer for which the participant is enrolled in the trial.
  • In Phase 2, participants must provide a sufficient and adequate formalin fixed paraffin embedded tumor tissue sample preferably from the most recent biopsy of a tumor lesion, collected either at the time of or after the diagnosis of locally advanced, recurrent, and/or metastatic disease has been made and from a site not previously irradiated. If no tumor tissue is available, a fresh biopsy will be required. Note: Tissue from needle or excisional biopsy or from resection is required.
  • Female participants must have a negative serum pregnancy test at screening (within 72 hours of first dose of study drug) if of childbearing potential or be of non-childbearing potential. Non-childbearing potential is defined as (by other than medical reasons):
  • ≥45 years of age and has not had menses for greater than 1 year,
  • Amenorrheic for ≥2 years without a hysterectomy and oophorectomy and a follicle-stimulating hormone value in the postmenopausal range upon pretrial (screening) evaluation,
  • Whose status is post hysterectomy, oophorectomy, or tubal ligation.
  • If of childbearing potential, female participants must be willing to use 2 highly effective contraceptive measures (defined in the informed consent form [ICF]) throughout the study, starting with the screening visit through 120 days after the last dose of study drug. Note: Abstinence is acceptable if this is the established and preferred contraception for the participant.
  • Male participants with a female partner(s) of childbearing potential must agree to use 2 highly effective contraceptive measures (defined in the ICF) throughout the trial starting with the screening visit through 120 days after the last dose of study drug is received. Males with pregnant partners must agree to use a condom; no additional method of contraception is required for the pregnant partner. Note: Abstinence is acceptable if this is the established and preferred contraception for the participant.
  • Is willing and able to comply with the requirements of the protocol.

Who cannot join

  • The participant must be excluded from participating in the trial if the participant:
  • Is currently participating and receiving trial therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks of the first dose of treatment.
  • Has an inadequate washout period prior to first dose of study drug defined as:
  • Received systemic cytotoxic chemotherapy or biological therapy within 3 weeks before first dose,
  • Received radiation therapy within 3 weeks before first dose, or
  • Had major surgery within 4 weeks before first dose.
Show all 26Show fewer
  • Has received prior therapy with:
  • Any antibody/drug targeting T-cell co-regulatory proteins (immune checkpoints) such as anti-PD-1, anti-ligand 1 of programmed cell death protein 1, or anti-CTLA-4 antibodies
  • For Phase 2: >1 systemic treatment regimen for the locally advanced recurrent, and/or metastatic cervical cancer for which the participant is considered for the study. Participants who received a systemic regimen immediately after progressing within 6 months of completing chemotherapy concurrent with primary radiation or adjuvant chemotherapy after radiation will only be considered as having 1 prior systemic regimen for the purpose of this criterion. Note: In Phase 1, prior treatment with a CTLA-4 antibody is permissible for subjects with metastatic melanoma.
  • Has persisting toxicity related to prior therapy of National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 (NCI-CTCAE) Grade >1 severity. Note: Sensory neuropathy or alopecia of Grade ≤2 is acceptable.
  • Is expected to require any other form of systemic or localized antineoplastic therapy while on trial (including maintenance therapy with another agent, radiation therapy, and/or surgical resection).
  • Has known severe hypersensitivity reactions to fully human monoclonal antibodies (NCI-CTCAE Version 4.03 Grade ≥3), any history of anaphylaxis, or uncontrolled asthma.
  • Is receiving systemic corticosteroid therapy ≤7 days prior to first dose of study treatment or receiving any other form of systemic immunosuppressive medication (corticosteroid use on study for management of immune-related adverse events, and/or a premedication for intravenous (IV) contrast allergies/reactions is allowed). Participants who are receiving daily corticosteroid replacement therapy are an exception to this rule. Examples of permitted therapy are daily prednisone at doses of 5 to 7.5 mg or equivalent hydrocortisone dose, and steroid therapy administered by topical, intraocular, intranasal, and/or inhalation routes.
  • Has a central nervous system tumor, metastasis(es), and/or carcinomatous meningitis identified either on the baseline brain imaging obtained during the screening period or identified prior to consent. Note: Participants with history of brain metastases that have been treated may participate provided they show evidence of stable supra-tentorial lesions at screening (based on 2 sets of brain images performed ≥4 weeks apart and obtained after the brain metastases treatment). In addition, any neurologic symptoms that developed either as a result of the brain metastases or their treatment must have resolved or be minimal and be expected as sequelae from treated lesions. For individuals who received steroids as part of brain metastases treatment, steroids must be discontinued ≥7 days prior to first dose of study drug.
  • Has active or history of autoimmune disease that has required systemic treatment within 2 years of the start of study treatment (that is, with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (that is, thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, et cetera) is not considered a form of immunosuppressive systemic treatment. Note: Participants with diabetes type 1, vitiligo, psoriasis, hypo-, or hyperthyroid disease not requiring immunosuppressive treatment are eligible.
  • Has had an allogeneic tissue/solid organ transplant.
  • Has or had interstitial lung disease or has had a history of pneumonitis that has required oral or IV corticosteroids.
  • Has an active infection requiring IV systemic therapy.
  • Has known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies).
  • Has known active hepatitis B, hepatitis C, or tuberculosis. Active hepatitis B is defined as a known positive hepatitis B surface antigen result. Active hepatitis C is defined by a known positive hepatitis C antibody result and known quantitative hepatitis C virus RNA results greater than the lower limits of detection of the assay.
  • Has clinically significant (that is, active) cardiovascular disease: cerebral vascular accident/stroke or myocardial infarction within 6 months of enrollment, unstable angina, congestive heart failure (New York Heart Association class ≥II), or serious uncontrolled cardiac arrhythmia requiring medication.
  • Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the participant's participation for the full duration of the study, or is not in the best interest of the participant to participate, in the opinion of the treating investigator.
  • Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
  • Is, at the time of signing informed consent, a regular user (including "recreational use") of any illicit drugs or had a recent history (within the last year) of substance abuse (including alcohol).
  • Is legally incapacitated or has limited legal capacity.
  • Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of balstilimab and/or zalifrelimab.

Trial locations and contacts

47 sites in 9 countries.

47 sites in 9 countries

United States13 sites

  • Providence Regional Cancer System

    Aberdeen, Washington, 98520

  • Augusta University

    Augusta, Georgia, 30912

  • CliniCore International

    Baytown, Texas, 77521

  • Chattanooga's Program In Women's Oncology

    Chattanooga, Tennessee, 37403

  • City of Hope National Medical Center

    Duarte, California, 91010

  • Comprehensive Care and Research Center

    Goodyear, Arizona, 85338

  • West Michigan Cancer Center

    Kalamazoo, Michigan, 49007

  • University of Miami

    Miami, Florida, 33136

  • Ochsner Cancer Institute

    New Orleans, Louisiana, 70121

  • University of Oklahoma

    Oklahoma City, Oklahoma, 73104

  • BRCR Medical Center, Inc

    Plantation, Florida, 33322

  • Swedish Cancer Institute

    Seattle, Washington, 98104

  • Cancer Treatment Centers of America

    Zion, Illinois, 60099

Other trials in United States

Ukraine10 sites

  • CI Dnipropetrovsk CMCH #4 of Dnipropetrovsk RC Dept of Chemotherapy SI Dnipropetrovsk MA of MOHU

    Dnipro, 49102

  • CI Transcarpathian Cl Onc Center Dep of Surgery #1 SHEI Ivano-Frankivsk NMU

    Ivano-Frankivsk, 76018

  • Communal Non-profit Enterprise Regional Center of Oncology

    Kharkiv, 61070

  • CI of Healthcare Regional Clinical Specialized Dispensary of the Radiation Protection, Department of Surgery

    Kharkiv, 61166

  • Khmelnytskyi Regional Oncological Dispensary

    Khmelnytskyi, 29000

  • Medical Clinic Innovacia, LLC

    Kiev, 07352

  • Kyiv Сity Clinical Oncological Center

    Kyiv, 03115

  • Medical Center Oncolife

    Kyiv, 04078

  • Limited Liability Company Adonis

    Kyiv, 08114

  • Treatment-Prevention Institution Volyn Regional Oncological Dispensary

    Lutsk, 43018

Other trials in Ukraine

Hungary8 sites

  • Magyar Honvedseg Egeszsegugyi Kozpont

    Budapest, 1062

  • Orszagos Onkologiai Intezet

    Budapest, 1122

  • Debreceni Egyetem

    Debrecen, 4032

  • Bacs-Kiskun Megyei Korhaz

    Kecskemét, 6000

  • Pecsi Tudomanyegyetem

    Pécs, 7624

  • Szegedi Tudomanyegyetem Szent-Gyorgyi Albert Klinikai Kozpont

    Szeged, 6720

  • Jasz-Nagykun-Szolnok Megyei Hetenyi Geza Korhaz-Rendelointezet

    Szolnok, 5004

  • Zala Megyei Szent Rafael Korhaz

    Zalaegerszeg, 8900

Other trials in Hungary

Spain6 sites

  • ICO l'Hospitalet - Hospital Duran i Reynals

    L'Hospitalet de Llobregat, 8908

  • START Madrid. Oncology Phase I

    Madrid, 28040

  • Hospital Universitario La Paz

    Madrid, 28046

  • Clinica Universidad de Navarra

    Pamplona, 31008

  • Hospital Universitario Virgen Macarena

    Seville, 41009

  • Hospital Universitari i Politecnic La Fe

    Valencia, 46026

Other trials in Spain

Australia4 sites

  • Linear Clinical Research

    Perth, Western Australia, 6009

  • Mater Research

    South Brisbane, 4101

  • Icon Cancer Care South Brisbane

    South Brisbane

  • Scientia Clinical Research

    Sydney

Other trials in Australia

Brazil2 sites

  • Clínica de Pesquisas e Centro de Estudos em Oncologia Ginecológica e Mamária Ltda.

    São Paulo, 01317

  • IBCC - Instituto Brasileiro de Controle do Câncer

    São Paulo, 03102

Other trials in Brazil

Poland2 sites

  • BioResearch Group SP. Z O.O.

    Nadarzyn, 05-830

  • Centrum Onkologii-Instytut im.M.Sklodowskiej Curie

    Warsaw, 02-781

Other trials in Poland

Georgia1 site

  • LLC Arensia Exploratory Medicine

    Tbilisi, 0112

Other trials in Georgia

Moldova1 site

  • ARENSIA Exploratory Medicine Unit, Institute of Oncology

    Chisinau, 2025

Other trials in Moldova

About this study

Official title: A Phase 1/2, Open-Label, Multi-Arm Trial to Investigate the Safety, Tolerability, Pharmacokinetics, Biological, and Clinical Activity of AGEN1884 in Combination With AGEN2034 in Subjects With Metastatic or Locally Advanced Solid Tumors, and Expansion Into Select Solid Tumors

This is a Phase 1/2, open-label study of zalifrelimab (AGEN1884) in combination with balstilimab (AGEN2034) in participants with locally advanced, recurrent and/or metastatic solid tumors including cervical cancer. Balstilimab is a novel, fully human monoclonal immunoglobulin G4 antibody, designed to block program cell death-1 (PD-1). Zalifrelimab is a novel, fully human monoclonal immunoglobulin G1 antibody, designed to block cytotoxic T-lymphocyte antigen-4 (CTLA-4).

Read the detailed description

The trial consists of 2 phases:

  • Phase 1: Dose escalation
  • Phase 2: Expansion in advanced cervical cancer

Phase 1: Dose Escalation:

The enrollment to the Phase 1 portion of the study is completed. The trial will consist of a 3+3 dose escalation that will evaluate different combination dose levels (CDL) of zalifrelimab and balstilimab in participants with locally advanced, recurrent and/or metastatic solid tumors.

Participants may be enrolled to the following CDL cohorts:

  • CDL1 - zalifrelimab 1 milligram/kilogram (mg/kg) every 6 weeks + balstilimab 1 mg/kg every 2 weeks (starting CDL)
  • CDL2 - zalifrelimab 1 mg/kg every 6 weeks + balstilimab 3 mg/kg every 2 weeks (maximum planned CDL)
  • CDL-1 - zalifrelimab 0.3 mg/kg every 6 weeks + balstilimab 1 mg/kg every 2 weeks (potential de-escalation CDL)

CDL1 will be the first to be tested. Dose escalation will continue until the maximum planned CDL (CDL2) is shown to be safe or the maximum tolerated dose (MTD) is reached. The MTD is defined as the CDL below which ≥33% of participants develop dose-limiting toxicities (DLT). The decision to escalate to the next cohort will be made by a safety monitoring committee (SMC), based on safety assessments after all participants of a cohort reached the end of the DLT observation period of 21 days. Should ≥2 DLTs be observed in CDL1, the SMC may open enrollment to CDL-1. The SMC will also select the CDL for Phase 2.

Each participant will receive the combination treatment for a maximum of 24 months or until confirmed disease progression, unacceptable toxicity, or any criterion for withdrawal from the trial or the investigational medicinal products occur. Participants who do not complete the DLT observation period of 21 days after the first dose, for reasons other than a DLT will be replaced. Additional participants will be backfilled, concurrently with the 3+3 dose escalation schema at the lower cleared CDL, to ensure that each cohort enrolls at least 10 participants. These additional participants at each dose level will have the purpose of generating additional safety, pharmacokinetics, and receptor occupancy data, and will not undergo formal DLT observation.

The SMC selected CDL2 (zalifrelimab 1 mg/kg every 6 weeks + balstilimab 3 mg/kg every 2 weeks) as the recommended phase 2 dose (RP2D).

Phase 2: Expansion in Select Tumors

To further characterize safety and efficacy, the following expansion cohort will be enrolled:

Advanced cervical cancer In Phase 2, the RP2D of balstilimab and zalifrelimab will be administered for a maximum of 2 years or until confirmed progression, unacceptable toxicity, or any criterion for stopping the study drugs or withdrawal from the trial occurs.

For the Phase 2 portion of the trial, an independent data monitoring committee will be established to evaluate safety and efficacy and an independent endpoint review committee will be established to adjudicate tumor response.

Conditions
Cervical Cancer
Being tested
Zalifrelimab, Balstilimab
Medical subject headings
Uterine Cervical Neoplasms

What participants receive

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

  • ZalifrelimabDrug

    Also called AGEN1884

    Zalifrelimab was administered over 30 minutes and following the infusion of balstilimab.

  • BalstilimabDrug

    Also called AGEN2034

    Balstilimab infusion was administered over 30 minutes.

Study groups in NCT03495882
Study groupRoleWhat they receive
Phase 1 - Dose 1: Zalifrelimab + BalstilimabExperimentalParticipants received zalifrelimab (1 mg/kg every 6 weeks [Q6W]) in combination with balstilimab (1 mg/kg every 2 weeks [Q2W]).
Receives: Drug: Zalifrelimab; Drug: Balstilimab
Phase 1 - Dose 2: Zalifrelimab + BalstilimabExperimentalParticipants received zalifrelimab (1 mg/kg Q6W) in combination with balstilimab (3 mg/kg Q2W).
Receives: Drug: Zalifrelimab; Drug: Balstilimab
Phase 2: Zalifrelimab + BalstilimabExperimentalParticipants received the RP2D of zalifrelimab (1 mg/kg Q6W) in combination with balstilimab (3 mg/kg Q2W).
Receives: Drug: Zalifrelimab; Drug: Balstilimab

What is being measured

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

  1. Phase 2: Objective Response Rate (ORR) - Independent Endpoint Review Committee (IERC)

    The ORR was defined as the percentage of participants with a confirmed best overall response (BOR) of partial response (PR) or complete response (CR), as determined by an IERC per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1).

    Measured: Up to 2 years

  2. Phase 1: Number of Participants Experiencing Dose-limiting Toxicities (DLTs)

    The number of participants with an occurrence of a DLT during dose escalation during the first 21 days of treatment in Phase 1 are reported. Any DLT immediately led to permanent withdrawal of zalifrelimab and balstilimab.

    Measured: First 21 days of treatment

Secondary outcomes (12)

  1. Phase 1: Maximum Drug Concentration Observed Postdose at Steady-state (Cmax-ss) of Balstilimab and Zalifrelimab

    Blood samples were collected for serum balstilimab and zalifrelimab concentration analyses. Each cycle was 6 weeks (42 days) long. Results are reported as micrograms/milliliter (ug/mL).

    Measured: Pre-dose, up to 4 hours post-dose (Day 1 of Cycle 2 and Cycle 3)

  2. Phase 2: Cmax-ss of Balstilimab and Zalifrelimab

    Blood samples were collected for serum balstilimab and zalifrelimab concentration analyses. Each cycle was 6 weeks (42 days) long.

    Measured: Pre-dose, up to 4 hours post-dose (Day 1 of Cycle 4)

  3. Phase 1: Area Under the Drug Concentration-time Curve From Day 0 to Day 14 at Steady-state (AUC0-14d-ss) of Balstilimab and Zalifrelimab

    Blood samples were collected for serum balstilimab and zalifrelimab concentration analyses. Each cycle was 6 weeks (42 days) long. Results are reported as day times ug/mL (day*ug/mL).

    Measured: Day 1 through Day 15 (Cycle 2 and Cycle 3)

  4. Phase 2: AUC0-14d-ss of Balstilimab and Zalifrelimab

    Blood samples were collected for serum balstilimab and zalifrelimab concentration analyses. Each cycle was 6 weeks (42 days) long.

    Measured: Day 1 through Day 15 (Cycle 4)

  5. Phase 1/2: Number of Participants With Serum Anti-drug Antibodies (ADAs) for Balstilimab and Zalifrelimab

    Blood samples were collected for serum balstilimab and zalifrelimab ADA determination.

    Measured: Pre-dose through Month 27

  6. Phase 2: ORR - Investigator

    The ORR was defined as the percentage of participants with a confirmed BOR of PR or CR, as determined by the investigator per RECIST 1.1.

    Measured: Up to 2 years

  7. Phase 2: Duration of Response (DOR)

    DOR was defined as time from first observation of response to first observation of documented disease progression (or death within 12 weeks after last tumor assessment), as determined by an IERC and investigator, per RECIST 1.1. Participants without an event at the analysis cutoff date were censored on date of last tumor assessment. DOR data are reported as 25th percentile estimated from Kaplan-Meier curve.

    Measured: Up to 3 years

  8. Phase 2: Disease Control Rate (DCR)

    DCR was defined as the percentage of participants with CR, PR, or stable disease (SD) without progressive disease (PD) within 81 days of study start, or durable SD following PD, as determined by an IERC and investigator, per RECIST 1.1.

    Measured: Up to 3 years

  9. Phase 2: Time to Response (TTR)

    TTR was defined as the time interval between the date of treatment initiation and the earliest date of first documented confirmed complete response or partial response based on independent radiologic review, as determined by an IERC per RECIST 1.1.

    Measured: Up to 2 years

  10. Phase 2: Progression-free Survival (PFS)

    PFS was defined as the interval from the date of first dose of investigational agent until the earliest date of PD, as determined by IERC and investigator assessment of objective radiographic disease assessments per RECIST 1.1, or death due to any cause if occurring sooner than progression.

    Measured: Up to 2 years

  11. Phase 2: Overall Survival (OS)

    OS was defined as the interval from the date of first dose of investigational agent until the date of death.

    Measured: Up to 2 years

  12. Phase 1: Receptor Occupancy (RO) on Circulating T Cells

    A validated flow cytometry-based assay was used to evaluate programmed cell death protein-1 (PD-1) RO on circulating T cells as an indication of target engagement of balstilimab. Blood samples were collected for the assay. Results are reported as a percentage of available drug receptors occupied (%RO) by balstilimab; the higher the percentage, the greater the engagement of balstilimab with the target receptor. Initial testing revealed technical limitations of the sample isolation procedure prior to the PD-1 RO assessment, causing the PD-1 RO assay to inaccurately reflect the actual PD-1 RO status in response to balstilimab/zalifrelimab combination treatment. As a result, further sample collection and subsequent testing was not conducted. Only initial test results are reported. Results reported as mean percentage of receptors occupied based upon data collected on Days 8, 15, 22, and 29 of Cycle 1 and Days 1 and 8 of Cycle 2 (each cycle was 6 weeks/42 days long).

    Measured: Days 8, 15, 22, and 29 (Cycle 1); Days 1 and 8 (Cycle 2)

Timeline

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

  1. First posted12 Apr 2018
  2. Study start18 Dec 2017
  3. Primary completion15 Jul 2022
  4. Study completion15 Jul 2022

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 1/2
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
175 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03495882
Sponsor's protocol ID
C-550-01
Status last verified
Jul 2026
First submitted
19 Jan 2018
Last updated
11 Aug 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • O'Malley DM, Neffa M, Monk BJ, Melkadze T, Huang M, Kryzhanivska A, Bulat I, Meniawy TM, Bagameri A, Wang EW, Doger de Speville Uribe B, Hegg R, Ortuzar Feliu W, Ancukiewicz M, Lugowska I. Dual PD-1 and CTLA-4 Checkpoint Blockade Using Balstilimab and Zalifrelimab Combination as Second-Line Treatment for Advanced Cervical Cancer: An Open-Label Phase II Study. J Clin Oncol. 2022 Mar 1;40(7):762-771. doi: 10.1200/JCO.21.02067. Epub 2021 Dec 21.

    PubMed 34932394

Questions about this trial

What is this clinical trial studying?

A Phase 1/2 study testing Zalifrelimab and Balstilimab in people with Cervical Cancer, run by Agenus Inc. at 47 sites in 9 countries.

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 26 inclusion and 26 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: finished, as of the sponsor's last update on 11 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 47 sites in United States, Ukraine, Hungary, Spain, Australia and 4 more countries. 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 combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

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?

Yes. Results are posted in the registry (first posted 11 Aug 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Phase 2: Objective Response Rate (ORR) - Independent Endpoint Review Committee (IERC) (time frame: Up to 2 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03495882, which also lists 1 linked publication.

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 11 Aug 2026; AzTrials last refreshed its copy on 8 Nov 2026.

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