Galectin Therapeutics Inc. announced top-line clinical data from the extension cohort of an investigator-initiated Phase 1b clinical trial of Belapectin, a galectin-3 inhibitor, in combination with KEYTRUDA® (pembrolizumab) in patients with metastatic melanoma and head and neck cancer. The study is conducted under the direction of Dr. Brendan D. Curti, M.D., a renowned cancer and melanoma expert. The extension study enrolled nine melanoma patients and five head and neck squamous cell carcinoma cancer patients. Compared to the initial phase 1b patients, reported earlier, the cohort in this extension study was heavily pretreated with systemic therapy, including chemotherapy, immunotherapy with checkpoint inhibitors and cytokines, melanoma mutation-directed therapies (BRAF inhibitors and MEK inhibitors), as well as surgery and radiation therapies (external and radio-labeled). Patients also had a high burden of metastasis, with the lungs, soft tissues, and the liver being the most frequently involved organs. Four of the nine melanoma patients had a choroidal (ocular) tumor as a primary site of their cancer and had also developed liver metastasis. The treatment consisted of Belapectin 4 mg/Kg of lean body mass administered every three weeks by infusion, after the infusion of pembrolizumab. Pembrolizumab was administered according to its label. Patients’ response was evaluated at day 85, according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. The median number of treatment cycles was four (range 3-15) for melanoma patients and five (range 4-8) for head and neck cancer patients. Melanoma patient results included one partial response, four stable disease, and four progressive disease, providing a disease control rate of 56% (five out of nine patients). Head and neck cancer patients observed included two stable disease and three progressive disease, providing a disease control rate of 40% (two out of five patients). The combination of Belapectin and pembrolizumab was well tolerated and appeared safe. The most frequent adverse event related to pembrolizumab, in six patients, was grade 1 (mild) pruritus (itching), a known and labeled side-effect of pembrolizumab. The second most frequent adverse event related to pembrolizumab was grade 2 fatigue in three patients. All other adverse events were mild (grade 1). There were no grade 3 or above adverse events. Similar to the initial phase 1 study results, the frequency and severity of toxicities related to pembrolizumab, notably immune-mediated adverse events, was less than anticipated. No adverse event was deemed related to belapectin.