PRS-344

PRS-344 is a bispecific antibody-Anticalin fusion protein designed for immuno-oncology applications, specifically targeting advanced or metastatic solid tumors. It combines a PD-L1-targeting antibody with 4‑1BB-targeting Anticalin proteins fused to each arm of the antibody’s C-terminal heavy chain. The drug acts by simultaneously blocking the PD-L1 pathway (checkpoint inhibition) and providing localized co-stimulatory activation of 4‑1BB on T cells within the tumor microenvironment. This dual mechanism aims to enhance T cell activation, proliferation, and antitumor activity in a manner dependent on tumor PD-L1 expression, potentially increasing efficacy while limiting systemic toxicity. Preclinical studies have shown that this approach is more potent than combining separate anti-PD-L1 and anti–4‑1BB antibodies[2][7]. The drug was originally developed by Pieris Pharmaceuticals using its proprietary Anticalin technology and has since been further developed by Palvella Therapeutics (following a merger) in collaboration with Servier[1][6].

Other names

Solabafusp alfa