The feasibility of tumor-infiltrating lymphocyte expansion in non-clear cell renal cell carcinoma.

580 Background: The treatment landscape for non-clear cell renal cell carcinoma (nccRCC) lacks personalized therapeutic options. Although adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) has been explored in the treatment of other solid tumors, its potential feasibility and role in nccRCC remains unclear. This study aims to evaluate the feasibility of TIL expansion in nccRCC tumors. Methods: In this IRB-approved study conducted at Moffitt Cancer Center, tumor fragments collected from patients with nccRCC were cultured for 4 weeks in media supplemented with high-dose IL-2 (6000 IU/mL). After the 4-week period, assessments were made of TIL expansion, TIL phenotype, and reactivity to autologous tumor, measured by IFNγ secretion. The percent of T-cell phenotypes among expanded TILs were compared using a paired Student's t-test for normally distributed data and a Wilcoxon signed-rank test for non-normally distributed data. Differences in TIL measures by histologic subtype and TNM staging were analyzed using Kruskal-Wallis testing, while tumor size and patient clinicodemographic data were evaluated with standard linear regression. Results: A total of 16 patients underwent nephrectomy with curative intent for high risk, localized nccRCC. Most patients were male (68.8%) with a median age at time of surgery of 60.3 years (Interquartile Range [IQR]: 50.4-63.9). Histologically, 9 tumors were classified as papillary type 1, two as papillary type 2, one as chromophobe, one as Xp11.2 translocation, and three as unclassified. TILs were successfully grown in all 16 samples, with an average of 47.3% (range: 6.25-100.0) of fragments successfully expanded. The average TIL yield per fragment was 1.24 x 10 7 cells (range: 1.60 x 10 6 – 2.75 x 10 7 ). Reactivity of TILs to autologous tumors was observed in 81.25% of samples. Across each TIL measure, no differences were noted among nccRCC histology subtypes, TNM status, or tumor size. A histologic breakdown of TIL and phenotypic data is provided in the table. Conclusions: In this study, all 16 nccRCC tumor fragments expanded TILs with viable reactivity and marked predominance of T-cells. These results suggest the novel potential for TIL-based therapy in nccRCC histologic subtypes and warrant further investigation. nccRCC TIL expansion measures and phenotype breakdown. Primarily CD3 + T-cells expanded (p=0.01), with a higher proportion of CD4 + T-cells than CD8 + T-cells (p=0.004). Measure, mean ± SD Papillary nccRCC (n=11) Non-Papillary nccRCC (n=5) % Fragment Expanded 54.8 ± 26.7 29.3 ± 19.8 Total TIL Per Fragment 1.2 x 10 7 ± 8.2 x 10 6 1.4 x 10 7 ± 1.0 x 10 7 % Reactive Fragments 65.2 ± 26.8 43.0 ± 46.2 % CD56 + of TIL Expansion 14.1 ± 26.2 9.8 ± 4.6 % CD3 + of TIL Expansion 80.7 ± 26.3 88.5 ± 3.4 % CD4 + of TIL Expansion 50.3 ± 22.6 66.9 ± 18.1 % CD8 + of TIL Expansion 22.5 ± 17.5 12.0 ± 10.2