By Kim Polacek, APR, CPRC - November 04, 2023
Uveal melanoma is a rare type of eye cancer. Less than 2,000 people are diagnosed with the disease annually in the United States. It is treatable, however, roughly half of uveal melanoma patients will develop metastatic disease, most commonly to the liver, drastically reducing their chance for survival.
Liver tumors can be difficult to treat due to physical and immunologic barriers that reduce the effectiveness of therapy. High intratumoral pressure can cause blood vessels to collapse or close off making it difficult for intravenous drugs to reach the malignant cells. There are also tumor suppressive mechanisms blocking immune response.
A new therapy and delivery system has the potential to help overcome some of the liver treatment barriers. The immunotherapy drug, a TLR-9 agonist named SD-101, is administered as a hepatic arterial infusion via a pressure enabled catheter. This allows the drug to make it through the narrowed blood vessels and into the liver tumors.
Clinical data presented at the Society for Immunotherapy of Cancer annual meeting found the therapy helped bolster an immune response in metastatic uveal melanoma patients. The phase 1 trial evaluated 56 patients who received the SD-101 treatment either alone (cohort A), in combination with nivolumab (cohort B) or in combination with nivolumab + ipilimumab (cohort C). In all cohorts, there was evidence of increased CD4+ and CD8+ T cell activity and a reduction in myeloid-derived suppressor cells within the tumor. Progression free survival, meaning the length of time between treatment and the advancement of the disease, was the highest in cohort B at 11.7 months.
“This study aims to address a clinically unmet need for this patient population. The results, both clinically and immunologically, are a promising first step, but further studies with more patients are needed to more definitively determine the efficacy of pressure-enabled drug delivery of SD-101 for uveal melanoma liver metastases,” said Dr. Ahmad Tarhini, senior member of Cutaneous Oncology and Immunology Departments and director of Cutaneous Clinical and Translational Research at Moffitt Cancer Center.
TriSalus Life Sciences, the company behind SD-101 and the pressure enabled delivery system, is opening a phase 2 study to further evaluate the therapy.