On April 17, 2026 Pyxis Oncology, Inc. (Nasdaq: PYXS), a clinical-stage company developing next-generation therapeutics for difficult-to-treat cancers, reported that it will present new preclinical data highlighting that a mouse analogue of MICVO (maMICVO) demonstrates anti-tumor activity in a preclinical head and neck squamous cell carcinoma (HNSCC) model as monotherapy, and synergistic anti-tumor activity in combination with anti-mouse PD-1. These data will be presented in a poster session at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026 in San Diego, California, held April 17 – April 22, 2026.

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"These new preclinical data are particularly compelling as they further reinforce MICVO’s clinical development in HNSCC, both as a novel monotherapy treatment and in combination with anti-PD-1," said Tom Civik, Interim Chief Executive Officer and Director of Pyxis Oncology. "An important finding from the data is that combination treatment with maMICVO and anti-mouse PD-1 demonstrated synergistic anti-tumor activity and greater tumor control than either treatment alone in an immunotherapy-refractory preclinical HNSCC model, highlighting MICVO’s novel three-pronged mechanism of action and its potential to meaningfully enhance response to immunotherapy. Following our mid-year 2026 MICVO Phase 1 monotherapy update in 2L+ R/M HNSCC, we look forward to sharing updated data from the ongoing Phase 1/2 combination dose escalation study of MICVO in combination with pembrolizumab for 1L/2L+ R/M HNSCC patients in the second half of 2026."

Micvotabart pelidotin (MICVO), is a first-in-concept antibody drug conjugate (ADC) that targets extradomain-B of fibronectin (EDB+FN), a non-cellular structural component of the tumor extracellular matrix (ECM). MICVO is designed to treat solid tumors through a three-pronged mechanism of action: direct cancer cell killing, bystander effect and immunogenic cell death. MICVO is currently being evaluated as monotherapy in a Phase 1 clinical study in patients with recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC) and in combination with Merck’s anti-PD-1 therapy, KEYTRUDA (pembrolizumab), in a Phase 1/2 clinical study in patients with R/M HNSCC and other solid tumors.

Poster Key Highlights:

Monotherapy with maMICVO inhibited tumor outgrowth in MOC2, a syngeneic preclinical model of HNSCC
maMICVO produced dose-dependent inhibition of EDB+FN-expressing MOC2 tumor outgrowth, with 6 mg/kg showing the strongest tumor growth inhibition
Treatment with maMICVO modulated the immune compartment of MOC2 tumors toward a more favorable immune-permissive environment for immunotherapy
Treatment with maMICVO reduced the overall abundance of immune-suppressive regulatory T cells (Tregs) in MOC2 tumors
maMICVO also increased the CD8 T cell-to-Treg ratio and enhanced the abundance of a progenitor exhausted T cell subset that is highly responsive to anti-PD-1 therapy

Combination treatment with maMICVO and anti-mouse PD-1 acted synergistically to produce greater tumor control than either treatment alone
The combination of maMICVO and anti-mouse PD-1 resulted in greater tumor control and tumor growth inhibition than monotherapy with either maMICVO or anti-mouse PD-1
Bliss independence analysis confirmed that maMICVO acted synergistically with anti-mouse PD-1 in a preclinical model unresponsive to anti-mouse PD-1 monotherapy
Poster Information:

Title: Mouse analog of micvotabart pelidotin, an antibody-drug conjugate targeting extradomain-B of fibronectin, demonstrates anti-tumor efficacy in an immunotherapy-refractory syngeneic head and neck squamous cell carcinoma model
Session Title: Antibody Technologies and Platforms 2
Date/Time: April 21, 2026 | 9:00 AM – 12:00 PM PT
Location: Poster Section 11
Poster Board Number: 14
Presentation Number: 4406

This poster presentation will also be available on the Pyxis Oncology website on the Scientific publications page following the event.

(Press release, Pyxis Oncology, APR 17, 2026, View Source [SID1234664507])