Pyxis Oncology (PYXS) Cantor Global Healthcare Conference 2025 summary

Clinical program overview

• Lead asset MICVO is an extracellular targeting ADC optimized for potency, permeability, and stability, currently in clinical trials for both monotherapy and combination with pembrolizumab in head and neck cancer.

• Phase I part one data showed significant tumor regression in six of nine tumor types, with head and neck cancer showing a 50% confirmed ORR and 100% disease control rate at the 3.6-5.4 mg/kg dose range.

• MICVO demonstrated responses in patients resistant to prior Cetuximab, platinum, PD-1, and other ADCs, indicating potential utility in refractory populations.

• No observed difference in response between HPV-positive and HPV-negative patients, suggesting broad applicability across subgroups.

• Current expansion cohort is dosing at 5.4 mg/kg, with a focus on dose optimization per Project Optimus guidelines.

Competitive landscape and positioning

• MICVO's 50% ORR in heavily pretreated (median fifth-line) head and neck patients compares favorably to Merus (37% ORR, median second-line) and Bicara (0% ORR, median second-line) in phase I.

• The agent is being positioned to address both current and emerging standards of care, with specific arms targeting platinum/PD-1-resistant and EGFR/PD-1-resistant populations.

• Ongoing efforts to enroll patients previously treated with Merus and Bicara to directly assess post-bispecific efficacy.

• Combination studies with pembrolizumab aim to compete with high response rates set by Merus and Bicara in combo settings (benchmark ~65% ORR).

• The company is leveraging a global site footprint and a mix of expert and generalist centers to optimize enrollment and access to diverse patient populations.

Safety and mechanistic insights

• Safety profile at 5.4 mg/kg shows no grade 3/4 neuropathies or ocular toxicities, with manageable neutropenia and cutaneous events, comparing favorably to other ADCs.

• One grade 5 event was deemed unrelated to treatment, occurring in a highly comorbid patient at a higher dose.

• Lower payload-related toxicities observed compared to other MMAE ADCs.

• Mechanistically, response does not correlate strictly with EDB expression; factors like protease concentration and tumor microenvironment acidity may influence efficacy.

• Bystander effect and extracellular targeting are highlighted as key differentiators, aligning with evolving ADC paradigms.