Pembrolizumab/Lenvatinib With and Without Healthy Donor FMT (hdFMT) in Relapsed/ Refractory (R/R) Melanoma

Despite treatment advances, 40-60% of melanoma patients do not respond or fail to respond durably; and the management of relapsed/refractory (R/R) disease remains an important problem for the field. The importance of intact immune surveillance function in controlling outgrowth of neoplastic transformations has been known for decades. Accumulating evidence shows a correlation between tumor-infiltrating lymphocytes in cancer tissue and favorable prognosis in various malignancies. In particular, the presence of CD8+ T-cells and the ratio of CD8+ effector T cells/FoxP3+ regulatory T-cells (T-regs) correlates with improved prognosis and long-term survival in solid malignancies, such as ovarian, colorectal, and pancreatic cancer; hepatocellular carcinoma; malignant melanoma; and renal cell carcinoma. Tumor-infiltrating lymphocytes can be expanded ex vivo and reinfused, inducing durable objective tumor responses in cancers such as melanoma. Targeting TAMs (tumor associated macrophages, which are innate immune cells of heterogeneous origins that accumulate within the tumor microenvironment (TME) as tumors progress and interfere with antitumor T cell mediated responses) via targeted depletion, inhibition of active migration, and/or promotion of activation and differentiation have been pursued as therapeutic strategies to increase efficacy of ICI therapy clinically and preclinically. The pembrolizumab/lenvatinib combination has been explored in several clinical settings and been granted approval for two indications including advanced endometrial carcinoma and RCC. In addition to tumor-intrinsic mechanisms supporting resistance to anti-PD-1, the gut microbiome is a major tumor-extrinsic regulator of responses to anti-PD-1; In this trial, that will be in the form of hdFMT (healthy donor fecal-microbiota transplant).