Pyxis Oncology shares fall 7% despite updated MICVO trial results

Pyxis Oncology (NASDAQ:PYXS) shares fell 7% on Tuesday after the biotechnology company released updated Phase 1 data for Micvotabart Pelidotin, or MICVO, in patients with previously treated recurrent or metastatic head and neck squamous cell carcinoma.

Among 33 efficacy-evaluable patients receiving MICVO at 5.4 mg/kg intravenously once every three weeks, the study recorded a confirmed objective response rate of 36% and a disease control rate of 94%.

Median progression-free survival reached 6.2 months, while the probability of overall survival at 12 months was 79%. Median overall survival had not been reached at the time of the analysis.

MICVO shows responses across patient subgroups

Pyxis said clinical activity was observed across several patient groups, including patients differentiated by HPV status and previous treatments.

Among patients previously treated with an EGFR inhibitor, the confirmed objective response rate was 28%. For those without prior EGFR inhibitor treatment, the response rate was 47%.

The company reported no new safety signals, with treatment-related adverse events generally consistent with other antibody-drug conjugates using auristatin payloads.

Of the 35 patients included in the safety analysis, 54.3% experienced Grade 3 or higher treatment-related adverse events, while 14.3% discontinued treatment because of adverse events. No treatment-related deaths were reported.

Pyxis plans pivotal Headliner study

Pyxis intends to advance MICVO into a pivotal Phase 3 trial called Headliner, with the study expected to begin in mid-2027.

Before launching the trial, the company expects to hold an End of Phase 2 meeting with the U.S. Food and Drug Administration during the first quarter of 2027.

Headliner is expected to enrol approximately 500 patients with second- or third-line recurrent or metastatic head and neck squamous cell carcinoma.

The randomised study will compare MICVO with the investigator’s choice of cetuximab, docetaxel or methotrexate.

MICVO is a first-in-concept antibody-drug conjugate targeting extradomain-B of fibronectin, a structural component found within the tumour extracellular matrix.

Despite the reported response and disease control rates, Pyxis Oncology shares moved lower following the clinical update.

Pyxis Oncology stock price