BOSTON — September 9, 2026
Pyxis Oncology, Inc. announced positive updated data from its ongoing Phase 1 monotherapy study of micvotabart pelidotin (MICVO) in patients with second-line and beyond recurrent/metastatic head and neck squamous cell carcinoma (2L+ R/M HNSCC). In the 5.4 mg/kg dose-cap efficacy-evaluable population, MICVO demonstrated a 36% confirmed objective response rate and 94% disease control rate, with rapid responses observed across key patient subgroups. Median progression-free survival was 6.2 months, while the 12-month overall survival probability reached 79% and median overall survival had not yet been reached. The updated findings strengthen the clinical development rationale for MICVO and support Pyxis Oncology’s plans to advance the program into a pivotal Phase 3 study, with the Headliner™ trial planned for initiation in mid-2027.
MICVO Demonstrates Activity Across HNSCC Patient Groups
MICVO showed clinically meaningful activity across HPV status and prior-treatment subgroups, supporting the potential breadth of its non-EGFR-targeted approach in heavily pretreated R/M HNSCC. Among 33 efficacy-evaluable patients treated at or below the 5.4 mg/kg dose cap, 75% of responders achieved a response by the first six-week scan and 83% of responders experienced more than 50% tumor reduction from baseline. Confirmed response rates were 35% in HPV-positive oropharyngeal cancer and 38% in HPV-unrelated disease, while patients with prior EGFR inhibitor treatment achieved a 28% response rate compared with 47% among those without prior EGFR inhibitor exposure. Pyxis Oncology said the results are particularly relevant as the first-line treatment landscape for HNSCC evolves and creates a potential need for additional treatment options following progression. MICVO’s activity in patients previously exposed to established therapies supports further evaluation in the 2L+ setting.
Dose Capping Supports MICVO Safety Strategy
The updated safety findings reinforce Pyxis Oncology’s dose-optimization strategy for MICVO, with no new safety signals identified in the 35-patient safety-evaluable population. Treatment-related adverse events were generally consistent with the prolonged auristatin exposure expected from an antibody-drug conjugate, while dose capping was implemented to reduce the frequency and severity of adverse events in patients with higher body weight. The company reported no treatment-related deaths, although treatment-related adverse events occurred in 91.4% of patients and Grade 3 or higher events occurred in 54.3%. Peripheral neuropathy was observed in 40% of patients, with higher-grade events occurring in 17.1%, and generally emerged after patients had received evidence of clinical benefit and prolonged treatment. Pyxis is advancing MICVO through Project Optimus, with an End of Phase 2 meeting with the FDA anticipated in the first quarter of 2027 to align on dose selection before the pivotal program begins.
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Pyxis Oncology Prepares Headliner Phase 3 Program
Pyxis Oncology plans to initiate the randomized Headliner Phase 3 study in mid-2027 following regulatory alignment on dose selection, marking the next major development milestone for MICVO. The planned study is expected to enroll approximately 500 patients with 2L+ R/M HNSCC whose disease has progressed following platinum-based therapy and anti-PD-1 treatment. Patients will be randomized to MICVO or investigator’s choice of cetuximab, docetaxel or methotrexate, with overall response rate and overall survival serving as co-primary endpoints. MICVO is a first-in-concept ADC targeting extradomain-B of fibronectin (EDB+FN), a non-cellular structural component of the tumor extracellular matrix, rather than EGFR. Pyxis also expects updated data from its Phase 1/2 MICVO combination study with KEYTRUDA® (pembrolizumab) in the fourth quarter of 2026. With regulatory planning underway and additional clinical data expected, Pyxis Oncology is positioning MICVO as its lead development program for addressing unmet treatment needs in recurrent and metastatic head and neck cancer.
Source: Pyxis Oncology, ,press release
