Sequential CD146 and GPC3 CAR-T Cell Therapy in Advanced Ovarian Cancer

Advanced ovarian cancer remains challenging to treat, especially in the relapsed or refractory setting. CD146 (also known as MUC18 or MCAM) is a cell adhesion molecule involved in tumor angiogenesis and metastasis; it is frequently overexpressed in ovarian cancer and has been associated with aggressive disease and poor prognosis. GPC3 (glypican-3) is an oncofetal antigen expressed in a subset of ovarian carcinomas (particularly clear cell histology) and has been identified as a potential immunotherapy target in ovarian cancer. By targeting both CD146 and GPC3, this dual CAR-T approach aims to address tumor heterogeneity and improve anti-tumor efficacy. Essen Biotech's CAR-T pipeline emphasizes multi-target strategies (including CD146) and innovative dual-CAR designs to overcome the solid tumor microenvironment, providing the rationale for sequentially administering two distinct CAR-T cell products in this study.

In the Phase 1 portion (dose escalation), patients will be enrolled in sequential cohorts to receive escalating doses of CD146 CAR-T cells followed by GPC3 CAR-T cells. A standard 3+3 dose escalation design may be used to identify the maximum tolerated dose (MTD) and any dose-limiting toxicities. Lymphodepleting conditioning with cyclophosphamide and fludarabine will be given prior to CAR-T infusion to enhance T-cell engraftment. Arm A consists of an infusion of CD146-targeted CAR-T cells at the assigned dose; after a short interval (e.g. 1-7 days), Arm B consists of an infusion of GPC3-targeted CAR-T cells. Patients are closely monitored during and after each infusion for acute toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The DLT observation period is typically the first 28 days following the sequential CAR-T infusions. If DLTs occur, dose levels may be adjusted accordingly. Once the Phase 1 portion establishes a recommended Phase 2 dose, the trial will expand into the Phase 2 portion.

In the Phase 2 expansion, additional patients will be treated at the established dose to further evaluate efficacy outcomes. Tumor response will be assessed by imaging (e.g. RECIST 1.1 criteria) at regular intervals. The primary endpoints in Phase 2 include Objective Response Rate (the proportion of patients achieving a complete or partial response). Secondary efficacy endpoints include Progression-Free Survival (time from CAR-T infusion to disease progression or death) and Overall Survival (time from CAR-T infusion to death from any cause). Patients will also be evaluated for duration of response and immunological correlative endpoints (such as CAR-T cell persistence in blood), as applicable. All participants will be followed for up to 36 months post-treatment for long-term safety surveillance and survival status. This trial design will provide critical initial data on the feasibility, safety profile, and potential anti-tumor activity of a sequential dual-CAR T-cell therapy in ovarian cancer patients who have exhausted standard therapies.

Inclusion criteria

• Expected survival time ≥3 months;
• Diagnosis: Histologically or cytologically confirmed epithelial ovarian carcinoma (including fallopian tube or primary peritoneal carcinoma considered as ovarian cancer) that is relapsed or refractory to standard therapies. Patients must have received and progressed on or after at least one line of platinum-based chemotherapy (or be platinum-resistant) and have no curative standard treatment options.
• Target Antigen Expression: Tumor must demonstrate positive expression of CD146 and GPC3 by immunohistochemistry (IHC) on a recent tumor tissue sample. Expression of both targets is required for eligibility (to ensure the presence of the CAR-T targets in the patient's cancer).
• Disease Status: Measurable disease as defined by RECIST 1.1 criteria (at least one measurable lesion on imaging).
• Age: Adults aged ≥18 years. (Patients must be legally adult and able to provide informed consent. Upper age limit may not be specified, but patients must meet other health criteria.)
• Performance Status: Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 (indicative of fully active or restricted in physically strenuous activity only).
• Organ Function: Adequate organ and bone marrow function, including: absolute neutrophil count (ANC) above a minimum threshold, platelet count above threshold, hemoglobin above threshold (transfusion allowed), serum AST/ALT and bilirubin ≤2× upper limit of normal (unless due to liver involvement by tumor), and adequate renal function (e.g. creatinine clearance ≥50 mL/min or per protocol criteria).
• Consent: Ability to understand and sign informed consent, and willing to comply with trial procedures and follow-up. Women of child-bearing potential must have a negative pregnancy test and agree to use effective contraception during the study and for a defined period after CAR-T cell infusion (due to unknown risks to a fetus).

Exclusion criteria

• Prior Therapy: Previous treatment with any CAR-T cell therapy or other gene-engineered T-cell therapy targeting CD146 or GPC3. (Patients who received prior immunotherapies such as checkpoint inhibitors are allowed if a washout period is met, but prior CAR-T could confound results or pose increased risk.)
• CNS Involvement: Active central nervous system (CNS) metastases or carcinomatous meningitis. (Patients with a history of CNS metastases that have been effectively treated and are radiographically stable off steroids may be eligible, per protocol specifics.)
• Comorbid Illness: Uncontrolled intercurrent illness including, but not limited to, active uncontrolled infection, clinically significant heart failure (e.g. NYHA Class III-IV), unstable angina or arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. (Patients with controlled chronic conditions may be eligible at the investigator's discretion.)
• Immunosuppression: Active hepatitis B or C infection with viremia, or known HIV infection with uncontrolled viral load. Patients requiring chronic systemic immunosuppressive therapy (e.g. for an autoimmune condition or organ transplant) are excluded, except for physiologic dose steroids.
• Pregnancy or Breastfeeding: Pregnant or breastfeeding women are excluded due to potential risks to the fetus or infant from the study treatment. Women of child-bearing potential who are unwilling or unable to use adequate contraception are not eligible.
• Other Malignancy: Presence of another active malignancy requiring treatment (with the exception of certain early-stage cancers or those in remission for a specified period, per protocol). This is to avoid confounding outcomes and ensure patient safety.
• Hypersensitivity: Known severe hypersensitivity to any component of the investigational CAR-T cell products or to the lymphodepletion chemotherapy drugs (cyclophosphamide, fludarabine).
• Other Exclusions: Any condition that, in the opinion of the investigator, would make the patient unsuitable for the study (such as life expectancy limited by comorbid illness, or significant laboratory abnormalities not covered above).