NK521 in the Treatment of Malignant Ascites Associated With Advanced Solid Tumors

NCT07561437 | Recruiting Early Phase 1

• 1 other identifier: NK521-01
• Study Type: interventional
• Target: 18
• Locations: 1 country
• Sites: 1

Brief Summary

Study Population: Adult subjects aged 18-75 years with relapsed/refractory advanced solid tumors (including liver, gastric, colorectal, ovarian cancer, etc.) and malignant ascites confirmed by cytology, who have failed at least 2 lines of standard systemic therapy. Study Design: This is a dose-escalation, single-center, open-label, prospective Phase 1 study. A total of 18 subjects will be enrolled and assigned to 2 administration groups (9 subjects each): Group A (Intravenous infusion): For subjects with small-volume malignant ascites. Group B (Intraperitoneal perfusion): For subjects with large-volume symptomatic malignant ascites. Each group will follow a conventional "3+3" dose-escalation design with 3 dose levels (1×10⁹, 3×10⁹, 6×10⁹ NK cells per dose), administered once weekly, 3 weeks per cycle, for 2 consecutive cycles. Primary Objectives: To evaluate the safety and tolerability, and to determine the dose-limiting toxicity (DLT) of NK521 administered intravenously and intraperitoneally. Secondary Objectives: To assess the preliminary anti-tumor efficacy including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), duration of response (DOR), puncture-free survival (PuFS), and changes in tumor markers, as well as health-related quality of life (HRQoL).

Conditions

Advanced Solid Tumors

Outcome Measures

Primary Outcomes (1)

• Incidence of Treatment-Emergent Adverse Events and dose-limiting toxicities [Safety and Tolerability]

  The incidence and severity of treatment-emergent adverse events, the occurrence of dose-limiting toxicities, and clinically significant laboratory abnormalities, to evaluate the safety and tolerability of the study treatment.

  Treatment-emergent adverse events are recorded from the first administration until the final follow-up visit, up to 24 months, and dose-limiting toxicities are monitored within the 28-day period after the last administration.

Secondary Outcomes (4)

• Objective Response Rate (ORR)

  From the first administration, assessed every 6 weeks until disease progression or death, whichever comes first, up to 24 months.

• Progression-Free Survival (PFS)

  From the first administration, assessed every 6 weeks until progression or death, up to 24 months.

• Overall Survival (OS)

  From the first administration, followed up every 3-6 months until death or study closure, up to 24 months.

• Malignant Ascites Control Rate

  From the first intraperitoneal administration, assessed every 3 weeks until the end of treatment, up to 24 months.

Study Arms (2)

Intravenous NK521

EXPERIMENTAL

Intervention: NK521 Cell Injection Route: Intravenous infusion Dose: 1×10⁹, 3×10⁹, 6×10⁹ cells

Biological: NK521 Cell Injection

Intraperitoneal NK521

EXPERIMENTAL

Intervention: NK521 Cell Injection Route: Intraperitoneal perfusion Dose: 1×10⁹, 3×10⁹, 6×10⁹ NK cells per administration Regimen: Once weekly, 3 weeks per cycle, for 2 consecutive cycles, plus investigator-selected systemic therapy

Biological: NK521 Cell Injection

Interventions

NK521 Cell Injection BIOLOGICAL

Gene-edited natural killer (NK) cell product with knockout of TIGIT, NKG2A, and TGF-β, administered via intravenous infusion or intraperitoneal perfusion for the treatment of malignant ascites associated with advanced solid tumors.

Intraperitoneal NK521; Intravenous NK521

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Pathologically diagnosed with relapsed/refractory advanced solid tumors, including but not limited to liver cancer, gastric cancer, colorectal cancer, ovarian cancer, etc.
• Complicated with malignant ascites with identifiable tumor cells in ascites. Patients with advanced solid tumors who have failed at least 2 lines of standard therapy.
• At least one measurable lesion on CT or MRI per RECIST v1.1.
• ECOG performance status 0-2.
• Life expectancy ≥3 months.
• All toxicities from prior antineoplastic therapy have resolved to Grade 1 (CTCAE v5.0) or baseline except alopecia and fatigue; subjects with long-term stable sequelae from prior therapy (e.g., platinum-induced neuropathy) are allowed.
• Women of childbearing potential must be non-lactating with a negative serum pregnancy test within 1 week before enrollment; all subjects must agree to use contraception from signing informed consent until 6 months after the last NK521 infusion.
• Able to comply with the study protocol and follow-up procedures.
• Voluntarily signed and provided written informed consent.

You may not qualify if:

• Symptomatic central nervous system (CNS) metastasis and/or carcinomatous meningitis.
• History of other malignancies within the past 3 years.
• Active, known or suspected autoimmune disease, excluding hypothyroidism requiring only hormone replacement therapy, skin diseases not requiring systemic therapy (e.g., vitiligo, psoriasis, alopecia), or diseases not expected to relapse without external triggers.
• History of immunodeficiency, including positive HIV test, other acquired or congenital immunodeficiency diseases, or organ transplantation.
• History of severe cardiovascular and cerebrovascular diseases, including but not limited to: severe cardiac arrhythmia or conduction abnormality requiring clinical intervention (e.g., ventricular arrhythmia, third-degree atrioventricular block); QTc interval \>480 ms on 12-lead ECG at rest; acute coronary syndrome, congestive heart failure, aortic dissection, stroke, or other Grade ≥3 cardiovascular/cerebrovascular events within 6 months before enrollment; NYHA Class ≥II heart failure or left ventricular ejection fraction (LVEF) \<50%; uncontrolled hypertension.
• Received radical radiotherapy within 4 weeks before enrollment; received local palliative radiotherapy within 2 weeks before enrollment.
• Not fully recovered from major surgery or trauma within 2 weeks before enrollment.
• Participated in another investigational drug trial and received investigational therapy or used an investigational device within 4 weeks before enrollment.
• Received cellular antineoplastic therapy within 1 year before dosing; received other antineoplastic therapy outside this protocol within 4 weeks before dosing, including but not limited to chemotherapy, molecular targeted therapy, hormonal therapy, immunotherapy, biotherapy, or Chinese herbal patent medicine with antineoplastic indications.
• Received blood transfusion, erythropoietin, granulocyte colony-stimulating factor (G-CSF), or granulocyte-macrophage colony-stimulating factor therapy within 2 weeks before enrollment.
• Received systemic therapy with corticosteroids (prednisone \>10 mg/day or equivalent) or other immunomodulatory agents (e.g., thymosin, interleukin-2, interferon) within 2 weeks before enrollment. Inhaled or topical corticosteroids are allowed in subjects without active autoimmune disease.
• Positive virology test for hepatitis B or hepatitis C at screening, meeting any of the following:
• HBsAg positive with positive HBV-DNA titer or above upper limit of normal (ULN);
• HCV antibody positive.
• Known hypersensitivity or intolerance to PD-1 monoclonal antibody.

Sponsors & Collaborators

• Base Therapeutics (Shanghai) Co., Ltd.: lead

Study Sites (1)

Cancer Hospital, Chinese Academy of Medical Sciences

Beijing, Beijing Municipality, 010, China

RECRUITING

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Arm 1: Intravenous NK521 Intervention: NK521 Cell Injection Route: Intravenous infusion Dose: 1×10⁹, 3×10⁹, 6×10⁹ cells Arm 2: Intraperitoneal NK521 Intervention: NK521 Cell Injection Route: Intraperitoneal perfusion Dose: 1×10⁹, 3×10⁹, 6×10⁹ cells

Study Record Dates

• First Submitted: April 22, 2026
• First Posted: May 1, 2026
• Study Start: March 9, 2026
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): October 1, 2028
• Last Updated: May 1, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)