Stipple Bio raised a $100 million Series A after emerging from stealth, targeting improved therapeutic windows in antibody-drug conjugates (ADCs) by engineering tumor-specific binders through epitope selection. The company’s lead program, STP-100, is designed to prevent off-target toxicity, with plans to enter clinical studies in early 2027. Stipple said the funding will support advancement of STP-100 into early clinical development and use its “Pointillist Platform” to identify additional tumor-specific cell-surface epitopes. The company positioned its differentiation upstream of ADC chemistry, focusing on how the binder engages the tumor surface. The financing also illustrates how investors are paying for platform capabilities that can expand ADC payload options and reduce safety liabilities, a persistent constraint in the field. Stipple reported a three-year cash runway and described flexibility for subsequent raises. For biotech dealmakers, the round is a reminder that even in a risk-sensitive market, investors continue to fund discovery platforms when there is a clear mechanistic reason to believe they can widen the ADC therapeutic window.