Solstice Oncology secured $225 million in a Series A to develop a next-generation immunotherapy targeting CTLA-4, advancing a medicine sourced from Harbour BioMed. The startup said its approach is designed to address limitations seen in prior CTLA-4 strategies, positioning the program for further clinical development in immunogenic tumor settings. The financing underscores continued capital intensity for immune checkpoint innovation, even as investors scrutinize differentiation versus existing CTLA-4 or combination regimens. The raise adds to a cluster of recent immuno-oncology funding designed to overcome established checkpoint biology constraints with updated modalities or targeting concepts.