Adoptive cell therapy with tumor-infiltrating lymphocytes supported by checkpoint inhibition across multiple solid cancer types

Abstract

Background: Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) has shown remarkable results in malignant melanoma (MM), while studies on the potential in other cancer diagnoses are sparse. Further, the prospect of using checkpoint inhibitors (CPIs) to support TIL production and therapy remains to be explored.

Study design: TIL-based ACT with CPIs was evaluated in a clinical phase I/II trial. Ipilimumab (3 mg/kg) was administered prior to tumor resection and nivolumab (3 mg/kg, every 2 weeks ×4) in relation to TIL infusion. Preconditioning chemotherapy was given before TIL infusion and followed by low-dose (2 10e6 international units (UI) ×1 subcutaneous for 14 days) interleukin-2 stimulation.

Results: Twenty-five patients covering 10 different cancer diagnoses were treated with in vitro expanded TILs. Expansion of TILs was successful in 97% of recruited patients. Five patients had sizeable tumor regressions of 30%-63%, including two confirmed partial responses in patients with head-and-neck cancer and cholangiocarcinoma. Safety and feasibility were comparable to MM trials of ACT with the addition of expected CPI toxicity. In an exploratory analysis, tumor mutational burden and expression of the alpha-integrin CD103 (p=0.025) were associated with increased disease control. In vitro tumor reactivity was seen in both patients with an objective response and was associated with regressions in tumor size (p=0.028).

Conclusion: High success rates of TIL expansion were demonstrated across multiple solid cancers. TIL ACTs were found feasible, independent of previous therapy. Tumor regressions after ACT combined with CPIs were demonstrated in several cancer types supported by in vitro antitumor reactivity of the TILs.

Trial registration numbers: NCT03296137, and EudraCT No. 2017-002323-25.

Keywords: adoptive; immunotherapy; lymphocytes; tumor-infiltrating.

Figure 1

Therapy regimen. Overview of the scheduled adoptive cell therapy in combination with conditioning chemotherapy, low-dose interleukin-2 and checkpoint inhibition. Created with BioRender.com. TIL, tumor-infiltrating lymphocyte.

Figure 2

Clinical efficacy and OS. (A) Best change in target lesion sum of all patients. The patients with disease control (PR and/or SD >4.5 months) are marked with light gray and listed with cancer diagnoses. (B) Swimmer’s plot showing the duration of response in the individual patients and indicating start of tumor regressions >30% of target lesions. (C) Kaplan-Meier plot of the OS in the benefit and non-benefit groups. The survival curves are compared with a log-rank test. *The patients with antitumor reactive cells in vitro. BOR, best overall response; CC, cholangiocarcinoma; CRC, colorectal cancer; HNSCC, head-and-neck squamous cell carcinoma; MM, malignant melanoma; OS, overall survival; PD, progressive disease; PR, partial response; SD, stable disease.

Figure 3

Computerized tomography (CT) scan images from patients with an objective response to therapy. Two patients had a partial response according to RECIST V.1.1. Images from baseline and 6 weeks after cell infusion in patient 8 with cholangiocarcinoma and patient 19 with HNSCC are shown. HNSCC, head-and-neck squamous cell carcinoma.

Figure 4

Phenotype analysis of TILs throughout expansion. (A) Single marker expression analysis of the unstimulated TILs before (unstimulated TILs), after initial in vitro expansion (young TILs) and after the REP TILs. Expression is shown as the fraction of CD3+ cells. (B) Comparison of CD103+ and CD8+CD103+TILs during the in vitro expansion according to disease control (partial response and/or stable disease >4.5 months). The difference was tested for significance with a non-parametric Mann-Whitney U test. CD4 expression is low in unstimulated TILs as the dissociation agent (collagenase IV) is known to cleave CD4. CM, central memory; EM, effector memory; EMRA, terminally differentiated effector memory; ns, not significant; REP, rapid expansion protocol; TIL, tumor-infiltrating lymphocyte.

Figure 5

In vitro antitumor reactivity of infusion product. Expression of reactivity markers in REP TILs from eight patients where antitumor in vitro reactivity was seen in more than 0.5% of CD3+ cells. The REP TILs are divided according to the dominant T-cell subset: either CD4 or CD8. Reactivity was assessed with intracellular flow cytometry after coculture with unstimulated autologous tumor material. REP TILs with expression of at least two markers (TNF-α, IFN-γ, CD107a or CD137) in more than 0.5% of all CD3+ cells were considered reactive. *Patients in the disease control group. **Patients in the disease control group with an objective response. CC, cholangiocarcinoma; CRC, colorectal cancer; HNSCC, head-and-neck squamous cell cancer; IFN-γ, interferon gamma; MM, malignant melanoma; REP, rapid expansion protocol; TIL, tumor-infiltrating lymphocyte; TNF-α, tumor necrosis factor-alpha.

Figure 6

TMB versus disease control of ACT. The resected tumor sample used for in vitro TIL expansion was examined for TMB. The TMB of 24/25 of the patients treated with ACT is shown together with the best overall response and the patients are divided according to disease control rate (PR and/or SD >4.5 months). Non-PR indicates SD or PD. ACC, adrenocorticocarcinoma; ACT, adoptive cell therapy; CC, cholangiocarcinoma; CRC, colorectal cancer; HNSCC, head-and-neck squamous cell carcinoma; MM, malignant melanoma; NCSLC, non-small cell lung cancer; PD, progressive disease; PR, partial response; SD, stable disease; TIL, tumor-infiltrating lymphocyte; TMB, tumor mutational burden.