Liposomal Irinotecan Plus Enlonstobart for Platinum-Resistant Recurrent Ovarian Cancer

An Exploratory Clinical Study of Liposomal Irinotecan Combined With Enlonstobart in Patients With Platinum-Resistant Recurrent Ovarian Cancer

This is a prospective, single-center, single-arm exploratory clinical study designed to evaluate the efficacy and safety of liposomal irinotecan combined with enlonstobart in patients with platinum-resistant recurrent ovarian cancer.

Eligible female participants with histologically or cytologically confirmed epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer, FIGO stage II-IV, will receive liposomal irinotecan and enlonstobart every 2 weeks. Tumor assessment will be performed every 8 weeks. Participants may discontinue study treatment in the event of disease progression, intolerable toxicity, withdrawal of consent, or other reasons judged by the investigator.

Study Overview

• Status: Not yet recruiting
• Conditions: Epithelial Ovarian Cancer; Primary Peritoneal Cancer; Platinum-resistant Recurrent Ovarian Cancer; Fallopian Tube Cancers
• Intervention / Treatment: Drug: Liposomal Irinotecan

Detailed Description

Ovarian cancer is one of the most common gynecologic malignancies and has the highest mortality among gynecologic cancers. Most patients are diagnosed at an advanced stage, and recurrence is common after standard surgery and platinum-taxane-based chemotherapy. For patients with platinum-resistant recurrent ovarian cancer, treatment options remain limited and new therapeutic strategies are needed.

Irinotecan is a topoisomerase I inhibitor with antitumor activity in ovarian cancer. Liposomal irinotecan is a liposomal formulation designed to prolong circulation time, increase tumor drug accumulation, and reduce systemic toxicity compared with conventional irinotecan. Immune checkpoint inhibitors have shown activity in selected tumor types, and preclinical and clinical evidence suggests that irinotecan may enhance the effect of anti-PD-1 therapy. Enlonstobart is an anti-PD-1 monoclonal antibody.

This exploratory study will evaluate the objective response rate, progression-free survival, overall survival, and safety of liposomal irinotecan combined with enlonstobart in patients with platinum-resistant recurrent ovarian cancer receiving second- to fourth-line treatment.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Phase 2

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Female participants aged 18 to 75 years, inclusive, at the time of signing informed consent.
2. Histologically or cytologically confirmed epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer, FIGO stage II-IV.
3. Platinum-resistant recurrent disease, defined as disease progression within 6 months after the last platinum-containing chemotherapy, and not platinum-refractory disease, defined as disease progression within 4 weeks after initial platinum-containing chemotherapy. Participants may have received up to two prior lines of non-platinum systemic therapy. Treatment with a PARP inhibitor or anti-angiogenic therapy after platinum-resistant recurrence will be counted as one line of therapy; maintenance treatment with a PARP inhibitor or anti-angiogenic therapy will not be counted as a treatment line.
4. Ability to provide sufficient qualified formalin-fixed paraffin-embedded tumor tissue samples or slides for PD-L1 testing. Participants who are unable to provide tumor tissue slides for certain reasons may be enrolled at the investigator's discretion.
5. At least one measurable lesion at baseline according to RECIST version 1.1. The measurable lesion must not have received prior local therapy such as radiotherapy. A lesion located within a previously irradiated area may be selected as a target lesion if disease progression has been confirmed.
6. ECOG performance status of 0 or 1.
7. Expected survival of at least 3 months.

8. Adequate organ function, meeting all of the following criteria without blood transfusion, hematopoietic stimulating factors, or medication correction of blood cell counts within 14 days before the first dose:

   1. Absolute neutrophil count ≥1.5 × 10^9/L;
   2. Platelet count ≥75 × 10^9/L;
   3. Hemoglobin ≥9 g/dL;
   4. Serum creatinine ≤1.5 × the upper limit of normal or creatinine clearance ≥50 mL/min;
   5. Total bilirubin ≤1.5 × the upper limit of normal, or ≤3 × the upper limit of normal for participants with Gilbert's syndrome;
   6. Alanine aminotransferase and aspartate aminotransferase ≤2.5 × the upper limit of normal, or ≤5 × the upper limit of normal for participants with liver metastases;
   7. Activated partial thromboplastin time and international normalized ratio ≤1.5 × the upper limit of normal, without anticoagulants or other drugs affecting coagulation function within 14 days before the first dose, except for participants requiring long-term anticoagulation due to underlying disease.
9. Toxicities caused by prior antitumor therapy must have recovered to Grade 1 or lower according to CTCAE version 5.0, except for residual alopecia and fatigue.
10. Participants must understand the study and voluntarily sign written informed consent before study entry.

Exclusion Criteria:

1. History of severe hypersensitivity reaction to monoclonal antibody preparations or uncontrolled allergic asthma.
2. Known untreated central nervous system metastases, or treated but still symptomatic central nervous system metastases. Participants with residual signs or symptoms related to central nervous system treatment may be eligible if neurological symptoms have been stable or improved for at least 2 weeks before screening.
3. History of primary immunodeficiency.
4. Active autoimmune disease or history of autoimmune disease. Participants with well-controlled type 1 diabetes mellitus, well-controlled hypothyroidism requiring only hormone replacement therapy, skin diseases not requiring systemic treatment such as vitiligo, psoriasis, or alopecia, or conditions not expected to recur without external triggers may be eligible for further screening.
5. Serious arterial or venous thrombotic events within 3 months before screening, such as transient ischemic attack, cerebral hemorrhage, cerebral infarction, deep venous thrombosis, or pulmonary embolism.
6. History of interstitial lung disease, except localized radiation-induced interstitial pneumonia, or noninfectious pneumonia requiring glucocorticoid therapy.
7. Prior treatment with any antibody or drug targeting T-cell costimulatory or immune checkpoint pathways, including PD-1, PD-L1, PD-L2, CTLA-4, OX40, or CD137 inhibitors.
8. Prior immune-related adverse event of CTCAE version 5.0 Grade 3 or higher after immunotherapy.
9. Major surgery or radical radiotherapy within 28 days before the first dose; palliative radiotherapy within 14 days before the first dose; or use of radiopharmaceuticals such as strontium or samarium within 56 days before the first dose.
10. Systemic antitumor therapy within 28 days before the first dose, including but not limited to chemotherapy, immunotherapy, macromolecular targeted therapy, or biological therapy such as tumor vaccines, cytokines, or growth factors used to control cancer. Small-molecule targeted therapy or oral fluoropyrimidines within 14 days before the first dose or within 5 half-lives, whichever is longer; or mitomycin C or nitrosoureas within 6 weeks before the first dose.
11. Receipt of a live attenuated vaccine within 28 days before the first dose or planned receipt of a live attenuated vaccine during the study.
12. Any active infection requiring systemic treatment by intravenous infusion within 28 days before the first dose.
13. Treatment within 14 days before the first dose with traditional Chinese patent medicines approved by the NMPA whose package inserts clearly state antitumor indications, or traditional Chinese herbal medicine documented in the medical record as being used for antitumor purposes.
14. Whole blood or blood component transfusion within 14 days before the first dose.
15. Treatment with glucocorticoids equivalent to prednisone >10 mg/day or other immunosuppressive agents within 14 days before the first dose.
16. Participation in another clinical trial and receipt of investigational treatment within 28 days before the first dose, calculated from the date of the last treatment in the previous clinical study, except participation in overall survival follow-up of a study.
17. Positive human immunodeficiency virus antibody or Treponema pallidum antibody; positive hepatitis B surface antigen and/or hepatitis B core antibody with hepatitis B virus DNA above the upper limit of normal of the testing laboratory; or positive hepatitis C antibody with hepatitis C virus RNA above the upper limit of normal of the testing laboratory.
18. History of active tuberculosis.
19. Pregnancy or breastfeeding.
20. Other malignancy that progressed or required treatment within 5 years before screening, except adequately treated basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, or cured carcinoma in situ such as breast carcinoma in situ.
21. Any other condition that may increase the risk associated with study treatment, interfere with interpretation of study results, affect study compliance, or otherwise make the participant unsuitable for the study in the investigator's judgment.
22. Any clinically significant gastrointestinal disease, including liver disease, bleeding, inflammation, obstruction, or diarrhea greater than Grade 2.
23. Current use or use within the past 2 weeks of strong CYP3A enzyme inducers or inhibitors and/or strong UGT1A inhibitors.
24. Prior use of liposomal irinotecan formulation or irinotecan.
25. Any condition that, in the investigator's judgment, makes the participant unsuitable for this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Experimental: Liposomal Irinotecan Plus Enlonstobart; Participants will receive liposomal irinotecan 70 mg/m^2 by intravenous infusion every 2 weeks and enlonstobart 240 mg by intravenous infusion every 2 weeks. Each treatment cycle is 14 days. Tumor assessment will be performed every 8 weeks, or every 4 cycles. Participants with disease progression or intolerable toxicity may discontinue study treatment and receive other antitumor therapy at the investigator's discretion.

Drug: Liposomal Irinotecan; Liposomal irinotecan 70 mg/m^2 will be administered by intravenous infusion every 2 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate	Objective response rate is defined as the proportion of participants who achieve complete response or partial response according to RECIST version 1.1.	Every 8 weeks, up to 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression-Free Survival	Progression-free survival is defined as the time from enrollment to the first occurrence of disease progression or death from any cause, whichever occurs first.	From enrollment to disease progression or death, up to 24 months
Overall Survival	Overall survival is defined as the time from enrollment to death from any cause. Participants who are alive at the end of the study will be censored at the date they were last known to be alive.	From enrollment to death from any cause, up to 24 months
Incidence and Severity of Adverse Events	Safety will be assessed by the incidence and severity of adverse events, including overall adverse events, adverse events by grade, Grade 3 or higher adverse events, and serious adverse events. Adverse events will be graded according to NCI CTCAE version 5.0.	From first dose to 30 days after the last dose, up to 13 months

Collaborators and Investigators

• Sponsor: Tianjin Medical University Cancer Institute and Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): May 30, 2026
• Primary Completion (Estimated): May 30, 2027
• Study Completion (Estimated): May 30, 2030

Study Registration Dates

• First Submitted: April 29, 2026
• First Submitted That Met QC Criteria: May 15, 2026
• First Posted (Actual): May 18, 2026

Study Record Updates

• Last Update Posted (Actual): May 18, 2026
• Last Update Submitted That Met QC Criteria: May 15, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Platinum-resistant ovarian cancer; Recurrent ovarian cancer; PD-1 inhibitor; Primary peritoneal cancer; Fallopian tube cancer; Overall survival; Epithelial ovarian cancer; Objective response rate; Progression-free survival; Liposomal irinotecan; Enlonstobart
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Endocrine System Diseases; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Neoplasms by Histologic Type; Genital Diseases, Female; Endocrine Gland Neoplasms; Neoplasms, Glandular and Epithelial; Ovarian Diseases; Adnexal Diseases; Genital Neoplasms, Female; Gonadal Disorders; Carcinoma; Fallopian Tube Diseases; Carcinoma, Ovarian Epithelial; Ovarian Neoplasms; Fallopian Tube Neoplasms; irinotecan sucrosofate
• Other Study ID Numbers: CSPC-DNY-CC-TJ01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data underlying the results reported in future publications will be shared, including demographic and baseline characteristics, treatment exposure, efficacy outcome data, safety data, quality-of-life data, and follow-up data. Data that could directly or indirectly identify participants, signed informed consent forms, raw source documents, and other confidential medical records will not be shared.
• IPD Sharing Time Frame: Data will be available beginning 6 months after publication of the main study results and for 5 years thereafter.
• IPD Sharing Access Criteria: Data will be available to qualified researchers who submit a scientifically sound research proposal. Requests will be reviewed and approved by the sponsor and principal investigator. Data will be shared after approval of the proposal and signing of a data use agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No