PYXS - BUY - 1Q26 Recap: Mid-2026 Ph1 2L HNSCC Dose Cap Data Could Define Pivotal Path If Efficacy Is Maintained With Safe, Durable Treatment

Research evidence excerpt

PYXS - BUY - 1Q26 Recap: Mid-2026 Ph1 2L HNSCC Dose Cap Data Could Define Pivotal Path If Efficacy Is Maintained With Safe, Durable Treatment

BIOTECHNOLOGY

PYXIS ONCOLOGY, INC. May 14, 2026

reduce Grade 3+ neuropathy, allowing them to be maintained durably on therapy and

adjunct care that are standard with other successful ADCs. Additionally, investors previously

expressed concern that the 4-5m of follow-up from the Dec 2025 data was not enough to

fully interrogate peripheral neuropathy which may be cumulative in nature. However, longer

follow-up from PFE's Padcev's Phase 1/2 EV-103 and Phase 3 EV-302 demonstrates that

onset of peripheral neuropathy is 2-6m and rates plateau from initial analyses all the way

out to 5yr follow-up (Exhibit 2). Other literature corroborates this, demonstrating that the

cumulative ramp-up occurs <4m before plateauing (Exhibit 1). As a result, safety follow-up

out to 6m for dose-capped patients should be sufficient to obtain comfort over a reduced

discontinuation rate.

What are the next steps for MICVO 2L+ HNSCC? Management believe the broad 2L

+ HNSCC opportunity of ~21K patients is underappreciated, particularly as 1L treatment

evolves toward EGFR + PD-1 for the majority that will leave a meaningful 2L population

with no established standard of care. Management consider the n=40 dose expansion

to be sufficient to define a pivotal population and plan next steps for a pivotal trial. The

enrolled patients include all PD-L1 CPS scores and both HPV-pos and HPV-neg. MICVO

has already demonstrated activity regardless of prior treatment and HPV-status, which

increases management’s confidence that MICVO is broadly relevant in HNSCC. Future 1L

development also remains a priority, with management set to report a data update in 2H26