Multispecific nanobody degraders co-deplete membrane receptors and enable targeted delivery of diverse payloads

Abstract Targeting membrane receptors underlies the success of antibody-drug conjugates (ADCs), yet single-receptor formats can be limited by heterogeneous expression, compensatory signaling, and variable internalization. Here we developed Multivalent Interchangeable Nanobody Degradation System (MINDS), a modular nanobody-Fc chassis that co-engages multiple membrane receptors, promotes their lysosomal co-depletion, and enables delivery of diverse intracellular payloads. As a proof of concept, we generated Tritazumab, a trispecific nanobody-Fc targeting three oncogenic receptors EGFR, cMET, and TfR1. Tritazumab incorporates a high-affinity, non-transferrin-competing anti-TfR1 nanobody that drives efficient uptake and lysosomal trafficking, enabling coordinated depletion of all three receptors. Across non-small cell lung cancer models, Tritazumab achieved rapid and sustained multi-receptor surface loss with picomolar degradation potency, reaching near-maximal depletion within approximately 1.5 hours. Conjugation of Tritazumab to MMAE preserved receptor binding and produced substantially greater antiproliferative activity and improved tumor selectivity relative to clinical ADCs in matched cell models, along with potent in vivo tumor growth inhibition and acceptable tolerability in a xenograft model. Extending the platform beyond cytotoxic payloads, a BRD4 molecular glue conjugate improved the selectivity window by > 100-fold and showed marked in vivo efficacy, while an EZH2-targeting PROTAC conjugate achieved an approximately 1,000-fold increase in intracellular degradation potency relative to the free PROTAC. These findings establish MINDS as a modular multispecific degrader-payload platform that integrates receptor co-depletion to enhance anticancer selectivity and efficacy. Competing Interest Statement The authors declare the following competing financial interest(s): J.J. is a cofounder and equity shareholder in Cullgen, Inc. and Valenyx Therapeutics, Inc, was a scientific cofounder and scientific advisory board member of Onsero Therapeutics, Inc., and is/was a consultant for Cullgen, Inc., EpiCypher, Inc., and Accent Therapeutics, Inc. M.K., is a cofounder and equity shareholder of Valenyx Therapeutics, Inc. The Jin laboratory received research funds from Celgene Corporation, Levo Therapeutics, Inc., Cullgen, Inc. and Cullinan Therapeutics, Inc. Y.S. is a cofounder of Antenna Biotech, and Valenyx Therapeutics, Inc. Y.Xiang. C.J. and Y.S. are co-inventors on a provisional patent covering the cMET Nb15. Y.Xiang. W.K. and Y.S. are co-inventors on a provisional patent covering the TfR1 Nb (S11 and N4). M.K., J.K., P.R.S., Z.D., Y.X., J.J., and Y.S. are co-inventors on a provisional patent covering MINDS.