Pressure on Pyxis despite promising PYX-201 data

Pyxis Oncology (Nasdaq: PYXS) has announced what look like encouraging early data from a Phase I trial of PYX-201, its lead antibody-drug conjugate (ADC), in solid tumors.

Investors took a different view, however, sending the company’s stock plummeting 45% on Thursday. A mixed outcome across indications may have added to concerns, with safety results also pointing to a limit on dosing levels.

PYX-201, which uniquely targets extradomain-B fibronectin (EDB+FN), is positioned as a potentially first-in-class ADC. Clinical activity was seen across six tumor types, including a 50% objective response rate in certain head and neck cancer patients.