Cell-Based Immunotherapy for HCC: Our Experiences and Future Directions

Study

Treatment arm

Control arm

Number of patients

Outcomes

Treatment arm vs control arm (%)

p-value

Takayama et al. [9]

CIK

Radical resection

150

5-year DFS

38 vs 22

p < 0.05

Radical resection

5-year OS

68 vs 62

p>0.05

Weng et al. [11]

CIK

TACE + RFA

1-year recurrence

9 vs 30

p < 0.05

TACE + RFA

1.5-year OS

100 vs 100

p>0.05

Hui et al. [10]

CIK + IL-2

Radical resection

127

5-year DFS

23 vs 11

p < 0.05

Radical resection

5-year OS

38 vs 37

p > 0.05

Kawata et al. [8]

LAK + IL-2

adriamycin

3-year DFS

50 vs 25

p>0.05

Adriamycin

3-year OS

71 vs 74

p>0.05

CIK cytokine-induced killer cells, DFS disease-free survival, HCC hepatocellular carcinoma, IL-2 interleukin-2, LAK lymphokine-activated killer cells, OS overall survival, RFA radio-frequency ablation, TACE trans-catheter arterial chemoembolization

Clinical trials of immunotherapy using other cells than CIK or LAK are ongoing or were completed according to the databases of clinical trials. According to ClinicalTrial.gov, eight cell-based immunotherapies were conducted as clinical trials so far (Table 5.2). Innate lymphoid cells including NK cells, NKT cells and γδT cells were used as effector cells in 3 trials. No evidence was demonstrated by phase III clinical trials with those innate lymphoid cells so far in any types of cancer, but in theory NK cells, NKT cells or γδT cells can target lack of MHC class I on cancer cells or phosphate antigen induced by abnormal metabolism in the tumor microenvironment. Tumor-infiltrating lymphocytes in 2 trials or dendritic cells in 2 trials were used to target cancers by tumor-specific immune responses.

Table 5.2

Clinical trials of immunotherapy for HCC registered in ClinicalTrial.gov

Cell type	Cancer	Phase	Facility	ID
γδT	HCC	I	Rennes University Hospital	NCT00562666
NK, IL-2-activated	HCC	I	University of Miami	NCT01147380
NK & NKT	Various cancers including HCC	I	Envita Medical Center, Inc.	NCT00909558
TIL	HCC, nasopharyngeal, breast	I	Sun Yat-sen University	NCT01462903
DC loaded with AFP peptides	HCC	I/II	Nantes University Hospital	NCT01128803
DC	HCC, melanoma, renal cell	II	Clinica Universidad de Navarra	NCT00610389
CD8⁺ TIL	Metastatic cancers including HCC	II	National Cancer Institute, NIH	NCT01174121
CIK	HCC	III	Sun Yat-sen University	NCT01749865

AFP alpha feto protein, CIK cytokine-induced killer cells, DC dendritic cells, HCC hepatocellular carcinoma, IL-2 interleukin-2, NK natural killer cells, NKT natural killer T cells, TIL tumor-infiltrating lymphocytes

In Japan, seven cell-based immunotherapies were conducted as clinical trials so far according to UMIN (Table 5.3). Two trials were γδT cell-based immunotherapy. Four trials were DC-based immunotherapy which intended to induce HCC-specific immune responses. As tumor antigen, tumor lysate was pulsed in DC in 1 trial (UMIN000005820). To load more specific tumor antigen in DC, tumor antigen mRNA-encoding DC was used in 1 trial (UMIN000005836). DC stimulated with OK-432, inactivated streptococcus pyogenes, were used in 1 trial to activate DC (UMIN000001701). Thus, various cell types and techniques were examined in the current clinical trials to enhance anti-tumor immune responses against HCC.

Table 5.3

Clinical trials of immunotherapy for HCC registered on UMIN in Japan

Cell type	Cancer	Phase	Facility	UMIN ID
Naïve T cells	HCC	II	Kyoto Prefectural University of Medicine	UMIN000003861
γδT	HCC	pilot	Tokyo Medical University	UMIN000004583
γδT	HCC	pilot	The University of Tokyo	UMIN000001418
DC	HCC	pilot	Tokyo Medical University/The University of Tokyo	UMIN000000971
DC, encoding cancer antigen mRNA	HCC, pancreatic	pilot	Yamaguchi University	UMIN000005836
DC, OK432-stimulated	HCC	I/II	Kanazawa University	UMIN000001701
DC, tumor lysate-pulsed	Various cancers including HCC	I/II	Tokyo Women’s Medical University	UMIN000005820

DC dendritic cells, HCC hepatocellular carcinoma

5.3 DC-Based Immunotherapy for HCC

Among various types of cell-based immunotherapy, sipuleucel-T is the only therapy which was verified to prolong overall survival of prostate cancer in phase III trial [7]. Sipuleucel-T comprises DC pulsed with tumor-specific antigen, PAP. If tumor-antigen is known, DC-based immunotherapy is a promising therapy to treat HCC according to the success in sipuleucel-T. Palmer reported that phase II trial of tumor lysate-pulsed DC infusion for patients with unresectable advanced HCC achieved disease control rate 28 % (combined partial response and stable disease) [15]. In the trial, hepatocellular carcinoma cell line HepG2 was used for source of tumor lysate. What is the best to load in DC, autologous tumor lysate, cell line-derived lysate, or HCC-specific peptides, is still controversial and to be determined in future.

We activated autologous DC from cancer patients with OK-432 before the infusion [16]. OK432-activated DC expressed high level of co-stimulatory molecules like CD80, CD83, and CD86. OK-432-stimulated DC also highly produced IL-12p40 and IFN-γ and revealed high tumoricidal activity against HCC cell lines like Hep3B and PLC/PRF/5 in in vitro assay. After TAE OK-432-stimulated DC were injected in hepatic artery via catheter. OK432-stimulated DC significantly prolonged recurrence-free survival compared to historical TAE control (P = 0.0017; Fig. 5.1). Although IFN-γ responses with PBMC specific to hTERT which is highly expressed by HCC as tumor antigen didn’t significantly increase after the OK-432-stimulated DC treatment, serum level of TNF, IL-9 and IL-15 was significantly higher in OK-DC group than TAE control patients. In mouse model of OK-DC treatment for HCC, OK-DC clearly induced tumor-specific immune responses against colon cancer cells [17]. It is still controversial that under which mechanism OK-432-stimulated DC exerts anti-tumor effect, tumor-specific immunity or non-specific direct killing. Although the mechanisms underlying the prolonged DFS caused by OK-432-stimulated DC treatment should still be elucidated, DC-based immunotherapy is a promising treatment for HCC.