In situ delivery of allogeneic natural killer cell (NK) combined with Cetuximab in liver metastases of gastrointestinal carcinoma: A phase I clinical trial

Abstract

Despite successful introduction of NK-based cellular therapy in the treatment of myeloid leukemia, the potential use of NK alloreactivity in solid malignancies is still elusive. We performed a phase I clinical trial to assess the safety and efficacy of in situ delivery of allogeneic NK cells combined with cetuximab in liver metastasis of gastrointestinal origin. The conditioning chemotherapy was administrated before the allogeneic NK cells injection via hepatic artery. Three escalating doses were tested (3.10⁶, 8.10⁶ and 12.10⁶ NK cells/kg) following by a high-dose interleukin-2 (IL-2). Cetuximab was administered intravenously every week for 7 weeks. Nine patients with liver metastases of colorectal or pancreatic cancers were included, three per dose level. Hepatic artery injection was successfully performed in all patients with no report of dose-limiting toxicity. Two patients had febrile aplasia requiring a short-term antibiotherapy. Grade 3/4 anemia and thrombopenia were also observed related to the chemotherapy. Objective clinical responses were documented in 3 patients and among them 2 occurred in patients injected with cell products harboring two KIR ligand mismatches and one in a patient with one KIR ligand mismatch. Immune monitoring revealed that most patients presented an increase but transient of IL-15 and IL-7 cytokines levels one week after chemotherapy. Furthermore, a high expansion of FoxP3⁺regulatory T cells and PD-1⁺ T cells was observed in all patients, related to IL-2 administration. Our results demonstrated that combining allogeneic NK cells transfer via intra-hepatic artery, cetuximab and a high-dose IL-2 is feasible, well tolerated and may result in clinical responses.

Keywords: NK cell; adoptive cell transfer; cetuximab; intrahepatic infusion.

Figure 1.

Cytotoxic activity of expanded NK cells. A. Adoptive NK cell transfer schedule. B-C, Expanded NK cell products from 7 donors were stimulated by K562 or Cetuximab coated-HT29 cell line for 4 h at effector to target ratio 2:1 before CD107 a staining. Expression of CD107 a was assessed by flow cytometry on CD3- CD56+ NK cells. B. Representative dot plot of one donor's NK cell product is shown (patient 2). Percentages refer to the percentage of CD107 a+ CD56+ cells among CD3- NK cells. Rituximab coated-HT29 cell line was used as control mAb (ctrl mAb). C. Each column indicates the percentage of CD107 a+ CD56+ CD3- NK cells from a single donor.

Figure 2.

Blood parameters recovery. Kinetic of lymphocytes (A), neutrophils (B), platelets (C) count and concentration of hemoglobulin (D) during the treatment period are shown. Each symbol represents an individual patient.

Figure 3.

Clinical activity. A Representative tumor responses evaluation by CT-scan and PET-scan before (left) and after (right) 2 months of NK cell transfer in patient 6 (PR). B, Objective responses according to the number of KIR ligand mismatch. PD, progressive disease; PR, partial response; Rd, dissociated response; SD, stable disease.

Figure 4.

Plasmatic cytokines levels. Plasma was collected from patients at the indicated times. Kinetics of IL-15 (A), IL-7 (B) IL-10 (C) and IFN-γ (D) are shown. Each symbol represents an individual patient.

Figure 5.

Monitoring of FoxP3⁺T_regs and PD-1+T through treatment. Flow cytometry analysis was performed from PBMC collected in each patient at the indicated time points. A. T_regs representative plot from one patient (#5). The kinetic of percentage (B) and absolute count of FoxP3⁺ T_regs are shown. The percentage of PD-1⁺ CD4 (D) and CD8 (E) T cells are shown. Baseline (BI)