Pyxis Oncology Announces Positive Updated Data from Phase 1 Monotherapy Study of Micvotabart Pelidotin (MICVO) in Second-Line and Beyond Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma (2L+ R/M HNSCC)

Q: What did the safety profile of MICVO look like at the 5.4 mg/kg dose with dose capping?

Among 35 safety‑evaluable patients, 91.4% experienced treatment-related adverse events (TRAEs) and 54.3% had Grade ≥3 TRAEs. Serious TRAEs occurred in 14.3%, and 14.3% discontinued treatment due to TRAEs, with median time to discontinuation of 162 days. TRAEs led to dose reductions in 40.0% of patients. ADC payload‑related events included cutaneous events in 48.6% (Grade 3 in 5.7%), peripheral neuropathy in 40.0% (Grade 3 in 17.1%), ocular events in 28.6% (Grade 3 in 5.7%), and pneumonitis in 11.4% (no Grade 3). No treatment‑related deaths occurred.

Q: How was dose capping implemented in the MICVO Phase 1 trial and why?

In December 2025, a dose cap was introduced for high body weight patients in the Phase 1 monotherapy study. Internal pharmacokinetic simulation modeling suggested that MICVO exposures achieved with dose capping and with adjusted ideal bodyweight dosing would be comparable. The company prioritized dose capping because of its operational simplicity and speed of implementation. The updated results focus on patients treated with 5.4 mg/kg every three weeks with a dose cap, where dose capping reduced the frequency and severity of adverse events in high body weight patients.

Q: What is MICVO and what regulatory designation has it received?

Micvotabart pelidotin (MICVO, formerly PYX‑201) is an antibody-drug conjugate targeting extradomain‑B of fibronectin (EDB+FN), a structural component of the tumor extracellular matrix that is selectively overexpressed in many solid tumors and largely absent from normal adult tissues. MICVO is designed to act through direct cancer cell killing, a bystander effect, and immunogenic cell death. The U.S. Food and Drug Administration has granted MICVO Fast Track Designation for adult patients with recurrent/metastatic head and neck squamous cell carcinoma whose disease has progressed following platinum-based chemotherapy and an anti‑PD‑(L)‑1 therapy.

MICVO showed notable response and PFS with a manageable safety profile in 2L+ head and neck cancer, supporting a planned Phase 3 trial in 2027.

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Rhea-AI Summary

Pyxis Oncology (PYXS) reported updated Phase 1 monotherapy data for micvotabart pelidotin (MICVO) in 2L+ recurrent/metastatic head and neck squamous cell carcinoma as of August 18, 2026.

Among 33 efficacy-evaluable patients treated at 5.4 mg/kg with dose capping, MICVO achieved a 36% confirmed objective response rate and 94% disease control rate, with 75% of responders improving by the first 6‑week scan and 83% showing >50% tumor reduction. Median progression-free survival was 6.2 months, and 12‑month overall survival probability was 79%, while median overall survival was not reached. Clinical activity was observed across HPV status and prior‑treatment subgroups.

In 35 safety-evaluable patients, no new safety signals were seen; 91.4% had treatment-related adverse events and 54.3% had Grade ≥3 events, with no treatment-related deaths. Dose capping reduced adverse events in high body weight patients. The company plans an FDA End of Phase 2 meeting in Q1 2027 and to start a pivotal ~500‑patient Phase 3 Headliner™ monotherapy trial in mid‑2027.

Positive

36% confirmed ORR and 94% DCR in 33 efficacy-evaluable 2L+ R/M HNSCC patients at 5.4 mg/kg with dose cap
Median PFS 6.2 months and 12‑month OS probability 79%, with median OS not reached as of August 18, 2026
Rapid and deep responses: 75% of responders by first 6‑week scan; 83% with >50% tumor reduction from baseline
Consistent activity across subgroups, including HPV+ oropharyngeal (35% ORR) and HPV‑unrelated (38% ORR) disease
No treatment-related deaths; serious TRAEs in 14.3% and discontinuations in 14.3% despite prolonged median treatment of 120 days
Regulatory momentum: FDA Fast Track designation for R/M HNSCC and alignment with FDA/EMA on a pivotal ~500‑patient Phase 3 design

Negative

High overall TRAE incidence: 91.4% of 35 patients experienced treatment-related adverse events at 5.4 mg/kg with dose cap
Grade ≥3 TRAEs in 54.3% of patients, including 42.9% with non‑hematologic Grade ≥3 events
Peripheral neuropathy common: 40.0% any grade and 17.1% Grade 3, with some cases leading to treatment discontinuation
14.3% discontinued treatment due to TRAEs, with median time to discontinuation of 162 days
Differential efficacy by prior EGFRi: ORR 28% with prior EGFR inhibitor versus 47% without prior EGFR inhibitor exposure

News Explained

MICVO remains in Phase 1; a roughly 500-patient pivotal trial is planned for mid-2027, contingent on FDA dose-selection alignment.

Pyxis Oncology reported updated Phase 1 monotherapy data for MICVO as of August 18, 2026; the study remains ongoing, and the release presents a move toward a pivotal Phase 3 program as planned rather than completed.

The planned Phase 3 study would randomize approximately 500 patients 1:1 to MICVO or investigators’ choice of cetuximab, docetaxel, or methotrexate, with initiation targeted for mid-2027 after FDA alignment on dose selection.

In the 35-patient safety-evaluable group, treatment-related adverse events led to dose reductions in 40.0% of patients and discontinuation in 14.3%; no treatment-related deaths were reported.

The next specified milestones are an FDA End of Phase 2 meeting in the first quarter of 2027, updated monotherapy overall-survival data in the first half of 2027, and combination-study data in the fourth quarter of 2026.

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Market reaction after Phase 1 clinical data: PYXS -18.98%

+2.1% Peak Tracked

-34.9% Trough Tracked

$2.80 $4.49 Day Range

$262.86M Market Cap

Following this news, PYXS has declined 18.98%, reflecting a significant negative market reaction. Argus tracked a peak move of +2.1% during the session. Argus tracked a trough of -34.9% from its starting point during tracking. Our momentum scanner has triggered 23 alerts so far, indicating elevated trading interest and price volatility. The stock is currently trading at $3.15. Trading volume is exceptionally heavy at 307.6x the average, suggesting significant selling pressure.

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Market Context

The Dec 18, 2025 MICVO Phase 1 update was followed by a -48.66% 24-hour reaction; that directly comp...

Analysis

The Dec 18, 2025 MICVO Phase 1 update was followed by a -48.66% 24-hour reaction; that directly comparable earlier readout provides historical market context for today’s updated monotherapy data.

Key Figures

Efficacy-evaluable population: 33 patients Confirmed objective response rate: 36% Disease control rate: 94% +5 more

Efficacy-evaluable population: 33 patients; Phase 1 monotherapy, 5.4 mg/kg dose-cap population
Confirmed objective response rate: 36%; Phase 1 monotherapy, 5.4 mg/kg dose-cap population
Disease control rate: 94%; Phase 1 monotherapy, 5.4 mg/kg dose-cap population
Median progression-free survival: 6.2 months; Phase 1 monotherapy, 5.4 mg/kg dose-cap population
12-month overall survival probability: 79%; Phase 1 monotherapy, 5.4 mg/kg dose-cap population
Grade ≥3 treatment-related adverse events: 54.3%; 19 of 35 safety-evaluable patients
Treatment-related deaths: 0; Phase 1 monotherapy safety population
Planned Phase 3 enrollment: Approximately 500 patients; Randomized 2-arm study in second- or third-line R/M HNSCC

Previous Clinical trial Reports

2 past events · Latest: Dec 18

Same Type 2 events

Dec 18
Phase 1 clinical data

24h Move

-48.7%

Reported preliminary MICVO Phase 1 responses and safety findings in recurrent/metastatic head and neck cancer.
Nov 20
Phase 1 clinical data

24h Move

-45.0%

Reported preliminary PYX-201 Phase 1 responses and announced a KEYTRUDA combination collaboration.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

confirmed objective response rate, progression-free survival, overall survival, antibody-drug conjugate, +2 more

6 terms

confirmed objective response rate medical

"with a 36% confirmed objective response rate (cORR) and 94% disease control rate"

The confirmed objective response rate is the percentage of patients in a clinical trial whose tumors shrink or disappear by a predefined amount and then show that same response again on a subsequent assessment, confirming the change was real and not temporary. It matters to investors because it is a standard measure of a drug’s measurable activity against disease and is often used by regulators, analysts, and partners to gauge clinical progress and commercial potential—think of it as counting only treatment successes that pass a second check.

progression-free survival medical

"Median progression-free survival (mPFS) was 6.2 months"

Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.

overall survival medical

"the 12-month overall survival (OS) probability was 79%"

Overall survival is the average or median length of time patients remain alive after starting a treatment or entering a clinical study, measured regardless of cause of death. Investors care because it is a clear, hard measure of a therapy’s real-world benefit — like timing how long a new battery actually runs — and strong improvements in overall survival can drive regulatory approval, market adoption and revenue potential.

antibody-drug conjugate medical

"is a first-in-concept antibody-drug conjugate (ADC)"

An antibody-drug conjugate is a targeted medicine that combines an antibody, which can identify specific cells, with a powerful drug designed to destroy those cells. This approach allows for precise treatment, minimizing damage to healthy tissue. For investors, developments in this area can signal advances in cancer therapies and potential growth opportunities in the biotech sector.

pharmacokinetic medical

"internal pharmacokinetic (PK) simulation modeling"

Pharmacokinetic describes how a drug moves through and leaves the body — how it is absorbed, spread to tissues, broken down and excreted — like tracking a package from pickup to delivery and disposal. For investors, these properties determine effective dose, safety risks, how often a medicine must be taken, and how reliably it works, which in turn influence clinical trial success, regulatory approval chances, production complexity and a drug’s commercial value.

fast track designation regulatory

"received Fast Track Designation from the U.S. Food and Drug Administration"

Fast track designation is a status the U.S. Food and Drug Administration grants to drugs intended to treat serious conditions and address an unmet medical need. It gives the developer more frequent communication with the FDA and can allow parts of the application to be reviewed on a rolling basis, and it may pave the way to priority review or accelerated approval. It can shorten development timelines, though it does not guarantee approval.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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09/09/2026 - 07:00 AM

MICVO demonstrated rapid and deep responses, with a 36% confirmed objective response rate (cORR) and 94% disease control rate (DCR), with clinical activity observed across HPV status and prior-treatment subgroups

Substantial survival outcomes include median progression-free survival (mPFS) of 6.2 months and 12-month overall survival (OS) probability of 79%, with clinical activity observed across HPV status and prior-treatment subgroups

No new safety signals observed; tolerability profile expected & consistent with prolonged auristatin exposure; dose capping reduced frequency and severity of adverse events in high body weight patients

MICVO potentially addresses significant unmet need in 2L+ R/M HNSCC, where evolving first-line treatment landscape is expected to create a demand for novel non-EGFRi treatment options

Data support advancement of MICVO into a pivotal program in 2L+ R/M HNSCC, with initiation of Phase 3 Headliner™ trial planned for mid-2027

Company to host webcast today at 7:30 a.m. ET

BOSTON, Sept. 09, 2026 (GLOBE NEWSWIRE) -- Pyxis Oncology, Inc. (Nasdaq: PYXS), a clinical-stage company developing next-generation therapeutics for difficult-to-treat cancers, today announced positive updated data as of the August 18, 2026 data cutoff date from its ongoing global Phase 1 monotherapy study evaluating micvotabart pelidotin (MICVO) in patients with second-line and beyond (2L+) recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC).

The updated results represent a population (N=33 efficacy evaluable) dosed at 5.4 mg/kg intravenously once every three weeks with a dose equivalent to or below a dose cap. These data demonstrated rapid and deep responses, with a 36% confirmed objective response rate (cORR) and 94% disease control rate (DCR). Median progression-free survival (mPFS) was 6.2 months, and the 12-month overall survival (OS) probability was 79% while median OS (mOS) has not yet been reached. Clinical activity was observed across key patient subgroups, including HPV status and prior treatment. No new safety signals were observed (N=35 safety evaluable), and dose capping reduced the frequency and severity of adverse events in high body weight patients.

MICVO, the company’s lead program, is a first-in-concept antibody-drug conjugate (ADC) targeting extradomain-B of fibronectin (EDB+FN), a non-cellular structural component of the tumor extracellular matrix. MICVO’s differentiated, non-EGFR targeting mechanism of action positions it to potentially serve a significant patient population and address unmet need in 2L+ R/M HNSCC as the first-line treatment landscape continues to evolve.

“There remains significant need for effective treatment options for patients with recurrent or metastatic head and neck cancer who progress following first-line therapy, particularly as the front-line treatment landscape continues to evolve,” said Alan L. Ho, M.D., Ph.D., Chief, Head and Neck Oncology Service and Attending Medical Oncologist, Memorial Sloan Kettering Cancer Center. “In this heavily pretreated population, these results demonstrated rapid and deep responses, along with progression-free survival and preliminary overall survival results that warrant further evaluation.”

“These updated data reinforce our conviction in MICVO’s potential to become an important treatment option for patients with cancer,” said Tom Civik, Chief Executive Officer and Chairman of Pyxis Oncology. “We are particularly encouraged by the combination of rapid and deep responses, substantial survival outcomes and a manageable safety profile. The data also provide important validation of our dose capping strategy, which was intended to maintain clinical activity while mitigating the risk of safety events. Based on feedback from the FDA and EMA on the design of our pivotal Phase 3 study, Headliner™, we believe MICVO is well positioned for success in a randomized trial, which we plan to initiate in mid-2027.”

Updated MICVO Phase 1 Monotherapy Trial Results as of August 18, 2026

Demographics
Table 1: Patient Demographics and Disease Characteristics – 5.4 mg/kg Dose Cap Population (N=35)

Table 1: Patient Demographics and Disease Characteristics – 5.4 mg/kg Dose Cap Population (N=35)

^{Data as of 18-Aug-2026}
^{1. cetuximab: Eli Lilly and Company & Merck KGaA; petosemtamab: Genmab A/S; ficerafusp alpha: Bicara Therapeutics}
^{Abbreviations: HPV: human papillomavirus; SCC: squamous cell carcinoma; EGFR: epidermal growth factor receptor; IO: immuno-oncology; ECOG: Eastern Cooperative Oncology Group; BMI: body mass index; PR: partial response; N/n: number of patients.}

Efficacy Data
Table 2: Efficacy Data Summary – 5.4 mg/kg Dose Cap Efficacy-Evaluable Population (N=33)

Efficacy Measure	5.4 mg/kg Dose Cap (N=33)
Confirmed objective response rate (cORR), % (n/N)	36% (12/33)
Disease control rate (DCR), % (n/N)	94% (31/33)
Responders achieving response by the first scan at six weeks, %	75%
Responders achieving >50% tumor reduction from baseline^*, %	83%
Median progression-free survival (mPFS), months, (95% CI)	6.2 (4.8-8.8)
12-month overall survival (OS) probability, %, (95% CI)	79% (58.1,90.3)
Median overall survival (OS), months	NR (NR-NR)

^{Data as of 18-Aug-2026}
^{*Per RECIST v1.1}
^{Abbreviations: n/N: number of patients.}

Table 3: Efficacy Data Across Key Patient Subgroups

Patient Subgroup	N	5.4 mg/kg Dose Cap Confirmed ORR, %	5.4 mg/kg Dose Cap Median PFS, months
HPV Status
HPV+ oropharyngeal	17	35%	6.2
HPV-unrelated	16	38%	5.9
Prior EGFRi
Yes	18	28%	5.0
No	15	47%	8.8
Prior Novel EGFRi*
Yes	5	40%	5.8
Prior Taxane
Yes	23	35%	6.2
No	10	40%	4.9

^{Data as of 18-Aug-2026}
^{*Prior novel EGFRi subgroup is a subset of patients with prior EGFRi treatment.}
^{Abbreviations: HPV: human papillomavirus; ORR: objective response rate; EGFRi: EGFR inhibitor; n/N: number of patients.}

Safety Data
No new safety signals were observed with MICVO. The tolerability data was consistent with that of other ADCs with auristatin payloads and was generally manageable. Adverse events of interest, including peripheral neuropathy, generally occurred after patients had received evidence of benefit, and after prolonged duration of treatment.

Table 4: Safety Data Summary – 5.4 mg/kg Dose Cap Population (N=35)

TRAEs	5.4 mg/kg with Dose Cap (N=35)
Treatment duration – median days (range)	120 (21-470)
All TRAEs, n (%)	32 (91.4%)
TRAEs of CTCAE Grade ≥ 3, n (%)	19 (54.3%)
Non-Hematologic TRAEs of CTCAE Grade ≥ 3, n (%)	15 (42.9%)
Serious TRAEs, n (%)	5 (14.3%)
TRAEs leading to treatment discontinuation*, n (%)	5 (14.3%)
TRAEs leading to treatment discontinuation days, median (min-max)	162 (104-212)
TRAEs leading to dose reduction, n (%)	14 (40.0%)
Treatment related deaths (Grade 5)	0
ADC Payload TRAEs of Interest	5.4 mg/kg with Dose Cap (N=35)
	Gr1/2	Gr3
Cutaneous, n (%)	17 (48.6%)	2 (5.7%)
Peripheral Neuropathy, n (%)	14 (40.0%)	6 (17.1%)
Peripheral Neuropathy days to onset, median (min-max)	82 (3-151)	166 (85-197)
Ocular, n (%)	10 (28.6%)	2 (5.7%)
Pneumonitis, n (%)	4 (11.4%)	0

^{Data as of 18-Aug-2026}
^{*TRAEs leading to discontinuation, N=1 Ocular, N=1 Muscle Weakness, N=3 Peripheral Neuropathy}
^{Abbreviations: ADC: antibody-drug conjugate; TRAE: treatment-related adverse event; CTCAE: Common Terminology Criteria for Adverse Events; Gr: grade; N: number of patients.}

MICVO Next Steps

Monotherapy
Pyxis Oncology is advancing the clinical development of MICVO through Project Optimus, a U.S. Food and Drug Administration (FDA) initiative focused on dose optimization and dose selection in oncology drug development. An End of Phase 2 meeting with the FDA to align on dose selection is anticipated in the first quarter of 2027. Updated overall survival data from the MICVO monotherapy study are expected in the first half of 2027.

The Company has aligned with the feedback from the FDA and the European Medicines Agency (EMA) on the design of the planned pivotal Phase 3 monotherapy study of MICVO in patients with second- or third-line R/M HNSCC who have progressed following treatment with both a platinum-based therapy and an anti-PD-1 therapy. The randomized, open-label, 2-arm study will enroll approximately 500 patients who will be randomized 1:1 to receive MICVO or investigators’ choice of cetuximab, docetaxel, or methotrexate. The co-primary endpoints of the study will be overall response rate and overall survival. Pyxis Oncology plans to initiate the study in mid-2027 following alignment with the FDA on dose selection.

Combination with KEYTRUDA® (pembrolizumab)
Pyxis Oncology expects to report updated data from the ongoing Phase 1/2 combination dose escalation study of MICVO and Merck’s (known as MSD outside of the US and Canada) anti-PD-1 therapy KEYTRUDA® (pembrolizumab) for 1L R/M HNSCC patients in the fourth quarter of 2026. Preliminary positive results for the treatment of 1L/2L+ R/M HNSCC were shared in December 2025. Additional data evaluating initial durability and selection of the recommended Phase 3 dose (RP3D) for the 1L combination are expected in the second half of 2027.

Webcast Information
Pyxis Oncology will host a live webcast today at 7:30 a.m. Eastern Time. To participate in the live event, please register using this link. The event and accompanying slides can be accessed by visiting the investor relations section of the Company's website at https://ir.pyxisoncology.com. An archived webcast will be available on the Company's website following the event.

About the MICVO Phase 1 Monotherapy Trial
The ongoing Phase 1 monotherapy study of MICVO is a multi-part study. Part 1 was a dose escalation study across multiple doses and tumor types, with initial results shared in November 2024. Part 2 is a dose expansion study in 2L+ R/M HNSCC. Preliminary Phase 1 study results in 2L+ R/M HNSCC were shared in December 2025.

The dose expansion portion of the study includes two arms: post-platinum and anti-PD-(L)1 patients (Arm 1) and post-EGFR inhibitor and anti-PD-(L)1 patients (Arm 2). Target enrollment for each arm was approximately 20 patients, and the Company completed target enrollment in the Phase 1 Part 2 monotherapy dose expansion study in the first quarter of 2026.

In December 2025, a dose cap was implemented for high body weight patients. Based on internal pharmacokinetic (PK) simulation modeling indicating that MICVO exposures with dose capping and adjusted ideal bodyweight (AIBW) dosing are expected to be comparable, dose capping was prioritized due to its operational simplicity and speed of implementation. The updated results reported today focus on patients treated at 5.4 mg/kg Q3W with a dose cap.

About Micvotabart Pelidotin (MICVO)
Micvotabart pelidotin (MICVO, formerly PYX-201) is an antibody-drug conjugate (ADC) that uniquely targets extradomain-B of fibronectin (EDB+FN), a non-cellular structural component of the tumor extracellular matrix. MICVO is designed to generate a multi-pronged attack on difficult-to-treat cancers by directly killing cancer cells, reducing extra-cellular matrix density, inhibiting tumor angiogenesis and mobilizing an anti-tumor immune response.

MICVO received Fast Track Designation from the U.S. Food and Drug Administration for the treatment of adult patients with R/M HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-PD-(L)-1 therapy.

About Pyxis Oncology, Inc.
Pyxis Oncology, Inc. is a clinical-stage biopharmaceutical company developing therapeutics for difficult-to-treat cancers. The Company’s lead candidate, 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). EDB+FN is selectively overexpressed in the tumor microenvironment of a wide range of solid tumors and largely absent from normal adult tissues. 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. Pyxis Oncology is focused on advancing MICVO, with the goal of improving outcomes for patients living with R/M HNSCC and contributing to meaningful progress in cancer treatment.

To learn more, visit www.pyxisoncology.com or follow us on LinkedIn.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Forward-Looking Statements

This press release contains forward-looking statements for the purposes of the safe harbor provisions under the Private Securities Litigation Reform Act of 1995 and other federal securities laws. All statements other than statements of historical facts contained in this press release, including without limitation statements regarding the Company’s plans to develop, manufacture and commercialize its product candidate, including micvotabart pelidotin (‘MICVO’); preliminary data, timing and progress of the Company’s ongoing clinical trials; the expected results of the Company’s clinical trials; the ability of preliminary, initial and topline clinical data to de-risk MICVO and be confirmed with clinical trial progression, including the safety, tolerability, and potential efficacy of MICVO; the potential differentiation, advantage or effectiveness of MICVO compared to other approved products or products in development; the dosage and treatment potential of MICVO; the size and future of the market; the plans and objectives of management, and the future results of operations and financial position of the Company, are forward-looking statements. These statements are neither promises nor guarantees, but are statements that involve known and unknown risks, uncertainties and other important factors that are in some cases beyond the Company’s control that may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: the risks inherent in drug research and development, the Company’s projected cash runway and potential needs for additional funding; the lengthy, expensive, and uncertain process of clinical drug development, including potential delays in or failure to obtain regulatory approvals; the Company’s reliance on third parties and collaborators to conduct clinical trials, manufacture its product candidate, and develop and commercialize its product candidate; and the Company’s ability to compete successfully against other drug candidate. Accordingly, investors should not rely upon forward-looking statements as predictions of future events. Except as required by applicable law, the Company undertakes no obligation to update publicly or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. Additionally, investors should read risk factors in the section titled “Risk Factors” set forth in Part II, Item 1A. of the Company’s Quarterly Report on Form 10-Q filed on August 13, 2026, and the Company’s other filings, each of which is on file with the Securities and Exchange Commission.

Pyxis Oncology Contact
IR@pyxisoncology.com

A photo accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/f0e9ef4e-0fec-44af-b949-8e3588e22e42

FAQ

What were MICVO’s efficacy results across key patient subgroups in the Phase 1 study?

In the 5.4 mg/kg dose-cap cohort, HPV+ oropharyngeal patients (N=17) had a 35% confirmed ORR and median PFS of 6.2 months. HPV‑unrelated patients (N=16) had a 38% ORR and median PFS of 5.9 months. Patients with prior EGFR inhibitor therapy (N=18) had a 28% ORR and median PFS of 5.0 months, while those without prior EGFR inhibitor (N=15) had a 47% ORR and median PFS of 8.8 months. Among patients with prior novel EGFR inhibitors (N=5), ORR was 40% with median PFS of 5.8 months. Prior taxane‑treated patients (N=23) had a 35% ORR and median PFS of 6.2 months, versus 40% ORR and 4.9‑month PFS in those without prior taxane (N=10).

What did the safety profile of MICVO look like at the 5.4 mg/kg dose with dose capping?

Among 35 safety‑evaluable patients, 91.4% experienced treatment-related adverse events (TRAEs) and 54.3% had Grade ≥3 TRAEs. Serious TRAEs occurred in 14.3%, and 14.3% discontinued treatment due to TRAEs, with median time to discontinuation of 162 days. TRAEs led to dose reductions in 40.0% of patients. ADC payload‑related events included cutaneous events in 48.6% (Grade 3 in 5.7%), peripheral neuropathy in 40.0% (Grade 3 in 17.1%), ocular events in 28.6% (Grade 3 in 5.7%), and pneumonitis in 11.4% (no Grade 3). No treatment‑related deaths occurred.

How is the planned Phase 3 Headliner™ monotherapy trial of MICVO in R/M HNSCC designed?

The planned pivotal Phase 3 monotherapy study will enroll approximately 500 patients with second- or third-line R/M HNSCC who have progressed after both platinum-based therapy and an anti‑PD‑1 therapy. It will be a randomized, open-label, 2‑arm trial with patients randomized 1:1 to receive MICVO or investigator’s choice of cetuximab, docetaxel, or methotrexate. The co‑primary endpoints will be overall response rate and overall survival. Pyxis Oncology plans to initiate this trial in mid‑2027, following alignment with the FDA on dose selection.

What are the next regulatory and clinical development milestones for MICVO monotherapy?

Pyxis Oncology is advancing MICVO under the FDA’s Project Optimus initiative for dose optimization. An End of Phase 2 meeting with the FDA to align on dose selection is anticipated in the first quarter of 2027. Updated overall survival data from the MICVO Phase 1 monotherapy study are expected in the first half of 2027. Initiation of the pivotal Phase 3 Headliner™ trial is planned for mid‑2027, after dose selection is finalized with the FDA.

What is the status of MICVO in combination with KEYTRUDA for head and neck cancer?

MICVO is being evaluated in an ongoing Phase 1/2 combination dose escalation study with KEYTRUDA (pembrolizumab) for first-line R/M HNSCC. Pyxis Oncology expects to report updated data from this study in the fourth quarter of 2026. Additional data on initial durability and selection of the recommended Phase 3 dose for the first‑line combination are expected in the second half of 2027. Preliminary positive results for MICVO plus KEYTRUDA in 1L/2L+ R/M HNSCC were shared in December 2025.

How was dose capping implemented in the MICVO Phase 1 trial and why?

In December 2025, a dose cap was introduced for high body weight patients in the Phase 1 monotherapy study. Internal pharmacokinetic simulation modeling suggested that MICVO exposures achieved with dose capping and with adjusted ideal bodyweight dosing would be comparable. The company prioritized dose capping because of its operational simplicity and speed of implementation. The updated results focus on patients treated with 5.4 mg/kg every three weeks with a dose cap, where dose capping reduced the frequency and severity of adverse events in high body weight patients.

What is MICVO and what regulatory designation has it received?

Micvotabart pelidotin (MICVO, formerly PYX‑201) is an antibody-drug conjugate targeting extradomain‑B of fibronectin (EDB+FN), a structural component of the tumor extracellular matrix that is selectively overexpressed in many solid tumors and largely absent from normal adult tissues. MICVO is designed to act through direct cancer cell killing, a bystander effect, and immunogenic cell death. The U.S. Food and Drug Administration has granted MICVO Fast Track Designation for adult patients with recurrent/metastatic head and neck squamous cell carcinoma whose disease has progressed following platinum-based chemotherapy and an anti‑PD‑(L)‑1 therapy.

Pyxis Oncology Announces Positive Updated Data from Phase 1 Monotherapy Study of Micvotabart Pelidotin (MICVO) in Second-Line and Beyond Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma (2L+ R/M HNSCC)