Pyxis Oncology Announces Positive Preliminary Phase 1 Data for Micvotabart Pelidotin (MICVO) in Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma

Rhea-AI Summary

Pyxis Oncology (NASDAQ: PYXS) reported preliminary Phase 1 data for micvotabart pelidotin (MICVO) in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) as of Nov 3, 2025. Key efficacy: 46% confirmed ORR and 92% DCR for MICVO monotherapy at 5.4 mg/kg (18 patients, 13 evaluable); 71% confirmed ORR and 100% DCR for MICVO + pembrolizumab (7 patients at 3.6/4.4 mg/kg).

Safety: no Grade 5 events; notable Grade ≥3 TRAEs in monotherapy (56%) and discontinuations in 28% linked to patients with high bodyweight; combination arm showed no TRAE-driven discontinuations. Company sold royalty rights for $11M and expects cash runway into Q4 2026. Updated monotherapy data expected mid-2026; combination updates expected 2H26.

Positive

• Monotherapy confirmed ORR of 46% at 5.4 mg/kg
• Monotherapy disease control rate 92%
• Combination confirmed ORR of 71% with pembrolizumab
• Combination disease control rate 100%
• Received $11M non-dilutive cash from royalty sale
• FDA alignment obtained on pivotal monotherapy study design

Negative

• Grade ≥3 TRAEs in 56% of monotherapy patients
• TRAEs led to treatment discontinuation in 28% of monotherapy patients
• Monotherapy dataset includes only 18 patients (13 evaluable)
• Combination dataset includes only 7 patients
• Durability and mature outcomes not yet available (updates mid-2026, 2H26)

Key Figures

Monotherapy ORR 46% Confirmed ORR in 2L+ R/M HNSCC at 5.4 mg/kg

Monotherapy DCR 92% Disease control rate in 2L+ R/M HNSCC at 5.4 mg/kg

Combo ORR 71% Confirmed ORR with MICVO + pembrolizumab (3.6/4.4 mg/kg)

Combo DCR 100% Disease control rate with MICVO + pembrolizumab

Monotherapy patients 18 patients Treated at 5.4 mg/kg IV Q3W in Phase 1 monotherapy

Combo patients 7 patients Treated at 3.6/4.4 mg/kg MICVO + 200 mg pembrolizumab

Royalty sale proceeds $11 million One-time cash payment for Enzeshu royalty rights

Cash runway Through 4Q 2026 Company’s stated operating runway post-royalty sale

Market Reality Check

$3.37 Last Close

Volume Volume 843,264 is 33% above the 20-day average of 632,876. normal

Technical Shares at $3.37 are trading above the 200-day MA of $1.99, yet 39.28% below the 52-week high.

Peers on Argus

PYXS fell 15.75% while peers showed mixed, mostly modest moves (e.g., CRBP -6.43%, KALA +5.9%). No evidence of a coordinated sector move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Nov 03	Earnings and update	Positive	+7.0%	Q3 2025 results, cash runway into 2H26, MICVO data timing.
Oct 13	Conference data	Positive	-6.8%	Translational MICVO data and three‑pronged mechanism at key meetings.
Oct 09	Management change	Neutral	+31.6%	Appointment of SVP, Investor Relations & Capital Markets.
Sep 30	Equity incentives	Neutral	-1.4%	Inducement stock option grants to seven new employees.
Aug 21	Conference participation	Positive	+13.8%	Planned presentations at September investor and ADC conferences.

Pattern Detected

News reactions have been mixed, with both substantial rallies and selloffs following corporate and scientific updates.

Recent Company History

Over the last few months, Pyxis has steadily highlighted MICVO’s development, from conference biology data to a Q3 update flagging preliminary Phase 1 results in 4Q25. Corporate items such as inducement grants and a senior IR hire have also moved the stock, with swings from -6.76% to +31.62%. Today’s clinical data provide the first detailed efficacy and safety picture in R/M HNSCC, building directly on the earlier translational and preclinical signals cited in the recent conferences and earnings updates.

Regulatory & Risk Context

Active S-3 Shelf Registration 2025-11-26

$350,000,000 registered capacity

An effective S-3 shelf filed on Nov 26, 2025 allows Pyxis Oncology to issue up to $350,000,000 of various securities over time, including a $150,000,000 at-the-market program, providing substantial financing flexibility that could be used alongside the MICVO development plan.

Market Pulse Summary

The stock is dropping -45.7% following this news. A negative reaction despite encouraging MICVO data fits a pattern where financing and balance-sheet considerations weigh heavily. Earlier filings noted substantial losses and going-concern language, while a $350,000,000 shelf adds potential future issuance overhang. Even with monotherapy DCR of 92% and combination DCR of 100%, investors may reassess risk around trial timelines, future capital needs, and execution on planned pivotal studies.

Key Terms

objective response rate (ORR) medical

"46% confirmed objective response rate (ORR) and 92% disease control rate..."

The objective response rate (ORR) is the percentage of patients in a clinical trial whose tumors shrink by a pre-set amount for a minimum time, counting both complete disappearance and meaningful partial shrinkage. Investors watch ORR because it gives an early, quantitative signal that a treatment is having a direct effect on disease—like the percent of people whose fever drops after taking a medicine—which can influence expectations for later trial success, regulatory approval, and market potential.

disease control rate (DCR) medical

"46% confirmed objective response rate (ORR) and 92% disease control rate (DCR)..."

The disease control rate (DCR) is the share of patients in a clinical trial whose cancer either shrinks, disappears, or does not get worse for a predefined period after treatment. For investors, DCR is a practical measure of a drug’s ability to halt disease progression — akin to counting how many cars in a fleet are kept running or fixed after a repair — and can influence a therapy’s regulatory prospects, market potential, and perceived risk.

antibody-drug conjugate (ADC) medical

"a first-in-concept antibody-drug conjugate (ADC) targeting extradomain-B..."

An antibody-drug conjugate (ADC) is a targeted medical treatment that combines an antibody, which acts like a guided missile seeking out specific cells, with a powerful drug to destroy those cells. It is designed to deliver medication directly to diseased cells, minimizing damage to healthy tissue. For investors, ADCs represent innovative therapies with potential for high growth, especially if they prove effective in treating difficult-to-cure conditions.

RECIST v1.1 medical

"including 1 complete response by RECIST v1.1 (Response Evaluation Criteria in Solid Tumors v1.1)."

RECIST v1.1 is a standardized set of rules used in cancer trials to measure how solid tumors change over time, defining when tumors shrink, grow, or stay the same based on imaging scans. Investors care because these consistent measurements determine key trial results and regulatory decisions—like whether a drug is seen as effective—so RECIST-based outcomes directly affect a therapy’s approval prospects, market potential, and company valuation.

ClinicalTrials.gov regulatory

"amended the ClinicalTrials.gov record for its first-in-human, open-label Phase 1 monotherapy trial..."

clinicaltrials.gov is a publicly accessible U.S. government database that lists details, timelines and status updates for medical studies testing drugs, devices or procedures. For investors it acts like a public calendar and scoreboard—showing when trials start, are delayed, or report results—so it helps gauge a company’s development progress, regulatory risk and potential value impact before official earnings or approvals are announced.

AI-generated analysis. Not financial advice.

• 46% confirmed objective response rate (ORR) and 92% disease control rate (DCR) observed with MICVO as monotherapy in 2L+ R/M HNSCC at 5.4 mg/kg
  
  
• 71% confirmed ORR and 100% DCR observed with MICVO in combination with KEYTRUDA^® (pembrolizumab) in 1L/2L+ R/M HNSCC at 3.6 mg/kg and 4.4 mg/kg
  
  
• Updated data from ongoing Phase 1 monotherapy study in 2L+ R/M HNSCC expected mid-2026; updated data from ongoing Phase 1/2 study evaluating MICVO in combination with KEYTRUDA^®, including in 1L/2L+ R/M HNSCC and other tumor types, expected 2H26
  
  
• Company to host webcast and conference call today at 8:30 a.m. ET
  

BOSTON, Dec. 18, 2025 (GLOBE NEWSWIRE) -- Pyxis Oncology, Inc. (Nasdaq: PYXS), a clinical-stage company developing next-generation therapeutics for difficult-to-treat cancers, today announced positive preliminary data from its ongoing Phase 1 clinical studies evaluating micvotabart pelidotin (MICVO), 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 (ECM), in patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). The update includes preliminary data from both the Phase 1 monotherapy study in 2L+ R/M HNSCC and the Phase 1/2 study evaluating MICVO in combination with Merck’s (known as MSD outside of the US and Canada) anti-PD-1 therapy, pembrolizumab, in 1L/2L+ R/M HNSCC.

“The preliminary data for MICVO as monotherapy and in combination with pembrolizumab add to the growing body of evidence supporting MICVO’s therapeutic potential and highlight its agility as a novel potential treatment option across the recurrent/metastatic head and neck squamous cell carcinoma landscape,” said Lara S. Sullivan, M.D., President, Chief Executive Officer and Chief Medical Officer of Pyxis Oncology. “The emerging response rates and disease control observed across these studies are highly encouraging, and the lack of early disease progression supports confidence in the durability profile as we advance MICVO in clinical development. We look forward to sharing mature data from the ongoing trials next year.”

“The current paradigm for treatment of recurrent/metastatic head and neck squamous cell carcinoma offers limited options and therapeutic mechanisms for our patients, so we are particularly pleased to observe a novel mechanism providing emerging evidence of such compelling benefit-risk profile,” said Glenn J. Hanna, M.D., Director, Center for Cancer Therapeutic Innovation and Center for Salivary and Rare Head and Neck Cancers at Dana-Farber Cancer Institute, and Associate Professor of Medicine, Harvard Medical School. “As we look ahead to where the treatment landscape may include next-generation EGFR combination therapies as first-line options for select patients, many will still lack effective treatments, particularly in later lines – which remains a significant unmet clinical need. MICVO monotherapy presents an intriguing potential option for these later-line patients, while the initial data in combination with pembrolizumab also shows promising potential synergies in first-line patients.”

The cutoff for all data reported below is as of November 3, 2025. Key findings are as follows:

Monotherapy
The ongoing MICVO Phase 1 monotherapy study is a two-part study. Part 1 was a dose escalation study across multiple doses and tumor types, with initial data shared in November 2024. Part 2, a dose expansion cohort at 5.4 mg/kg in 2L+ R/M HNSCC, is currently ongoing. The data below incorporate all R/M HNSCC patients dosed at 5.4 mg/kg in the MICVO Phase 1 monotherapy study.

• 18 patients were treated at 5.4 mg/kg; intravenous (IV) dosed every three weeks (Q3W)
  • 13 patients were evaluable for response (≥1 post-baseline scan within protocol limits, or discontinued early due to disease progression)
  • All patients treated had prior systemic therapy, including:
    • Median of 3 prior lines of therapy
    • 100% (18/18) had prior platinum-based therapy
    • 100% (18/18) had prior checkpoint inhibitor therapy
    • 67% (12/18) had prior taxane therapy
    • 50% (9/18) had prior EGFR targeting therapy
• Confirmed overall response rate (ORR) of 46% (6/13)¹, including 1 complete response by RECIST v1.1 (Response Evaluation Criteria in Solid Tumors v1.1).
  • Confirmed responses observed in both arms of dose expansion: post platinum & anti-PD(L)-1 experienced patients (Arm 1) and post EGFRi and/or anti-PD(L)-1 experienced patients (Arm 2)
    • Arm 1: 60% confirmed ORR (N=5)
    • Arm 2: 25% confirmed ORR (N=4)
  • Confirmed responses observed in patients with HPV-positive, HPV-negative, and HPV-not applicable tumors
• Disease control rate (DCR) of 92% (12/13)
  • 12 patients demonstrated significant tumor regression or tumor control
  • 1 patient with progressive disease had a verrucous subtype of HNSCC, which is often resistant to chemotherapy and typically managed surgically
• MICVO was generally well tolerated, with no Grade 4 ADC payload treatment-related adverse events (TRAEs) of interest observed. No Grade 5 events occurred.
  • TRAEs were observed in 89% (16/18) of patients
  • Grade ≥3 TRAEs occurred in 56% (10/18) of patients
  • TRAEs leading to treatment discontinuation were observed in 28% (5/18) of patients
    • 100% (5/5) of patients who had TRAEs leading to treatment discontinuation had “high bodyweight” (defined as at least 10% above adjusted-ideal bodyweight)
    • Adjusted Ideal Bodyweight (AIBW) dosing, which has demonstrated improved tolerability without sacrificing activity in clinical studies of other ADCs, is planned to be implemented in ongoing and future clinical studies

Combination Therapy
The ongoing MICVO Phase 1/2 study evaluating MICVO in combination with KEYTRUDA^® is part of a Clinical Trial Collaboration Agreement with Merck (known as MSD outside the US and Canada) and is currently in dose escalation across multiple doses and tumor types, including 1L/2L+ R/M HNSCC. The data below incorporate all R/M HNSCC patients dosed in the MICVO Phase 1/2 combination study at 3.6 mg/kg and 4.4 mg/kg.

• 7 patients were treated in total, 4 at 3.6 mg/kg and 3 at 4.4 mg/kg of MICVO, plus fixed dose 200 mg of pembrolizumab; IV Q3W
  • All patients were evaluable for response (≥1 post-baseline scan within protocol limits, or discontinued early due to disease progression)
  • All patients treated to date were HPV-positive  
    • Enrollment of HPV-negative and HPV-not applicable patients is anticipated as additional global clinical trial sites are activated
  • All patients treated had prior systemic therapy, including:
    • N=4, 1L HNSCC, median of 1 prior therapy
      • 100% (4/4) had prior platinum-based therapy administered with radiation in the adjuvant or definitive setting
      • 25% (1/4) had prior taxane administered in the neoadjuvant setting
    • N=3, 2L+ HNSCC, median of 3 prior lines of therapy
      • 100% (3/3) had prior platinum-based therapy
      • 100% (3/3) had prior checkpoint inhibitor therapy
      • 33% (1/3) had prior taxane therapy
• Confirmed overall response rate (ORR) of 71% (5/7)¹
  • Responses occurred across a range of PD(L)-1 CPS scores (CPS ≥1 to CPS >20)
  • Responses were observed in patients who received and had disease progression following prior checkpoint inhibitor treatment
• DCR of 100% (7/7)
  • All 7 patients demonstrated significant tumor regression
• MICVO was generally well tolerated, with no Grade 3 or Grade 4 ADC payload TRAEs of interest observed. No Grade 5 events occurred.
  • TRAEs were observed in 86% (6/7) of patients
  • There were no TRAEs leading to treatment discontinuation
  • Lack of overlapping toxicities between MICVO and KEYTRUDA^® observed to date
    

MICVO Next Steps
In mid-2026, Pyxis Oncology plans to present updated data from the ongoing Phase 1 monotherapy study in 2L+ R/M HNSCC, which is expected to include additional patients and initial durability data. In the second half of 2026, the company also plans to present updated data from the ongoing Phase 1/2 study evaluating MICVO in combination with pembrolizumab, including in 1L/2L+ R/M HNSCC and other tumor types.

Pyxis Oncology has received FDA alignment on the clinical trial design for a planned pivotal monotherapy study in 2L + R/M HNSCC. The Company is currently evaluating the path forward to pivotal studies for MICVO as monotherapy and in combination with pembrolizumab, respectively, and expects to provide additional detail in 2026.
  
Company Update
Pyxis Oncology completed sale of its rights to royalties from the commercialization of Enzeshu^® (Suvemcitug for Injection) for a one-time cash payment of $11 million. This non-dilutive funding will support the development of MICVO. As part of Pyxis Oncology's acquisition of Apexigen, Inc. in August 2023, the Company acquired rights to royalties on Enzeshu and another asset discovered using APXiMAB, Apexigen's proprietary antibody discovery platform. The Company’s current cash runway is expected to fund operations through data milestones and into the fourth quarter of 2026.

Conference Call Information
Pyxis Oncology will host a live conference call and webcast at 8:30 a.m. ET today to review the preliminary Phase 1 clinical trial data. Participants may register for the conference call here. A webcast of the call will also be available under "Events and Presentations" in the Investors section of the Pyxis Oncology website at https://ir.pyxisoncology.com/. The archived webcast will be available on Pyxis Oncology’s website approximately two hours after the conference call and will be available for 30 days following the call.

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 tumor cell killing, bystander effect and immunogenic cell death. MICVO is currently being evaluated in Phase 1 clinical studies in patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) and other solid tumors, both as monotherapy and in combination with Merck’s anti-PD-1 therapy, KEYTRUDA^® (pembrolizumab). 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 and follow us on LinkedIn.

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.

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

Dr. Hanna receives institutional research support and funding from, and has served in a consulting or advisory role for, Pyxis Oncology.

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 presentation, 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 their product candidates, and develop and commercialize their 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 November 3, 2025, and our other filings, each of which is on file with the Securities and Exchange Commission.

Pyxis Oncology Contact
Alex Kane
IR@pyxisoncology.com

Media
Cailyn McCutcheon
Real Chemistry
cmccutcheon@realchemistry.com

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¹ One patient for monotherapy and one patient for combination therapy confirmed response after November 3, 2025 data cutoff

FAQ

What were the confirmed ORR and DCR for PYXS MICVO monotherapy in R/M HNSCC?

Confirmed overall response rate was 46% with a disease control rate of 92% at 5.4 mg/kg.

What efficacy did PYXS report for MICVO plus KEYTRUDA (pembrolizumab) in R/M HNSCC?

The combination showed a confirmed ORR of 71% and a DCR of 100% across 7 treated patients.

When will Pyxis (PYXS) provide updated MICVO monotherapy data?

Updated Phase 1 monotherapy data are expected in mid-2026, including additional patients and initial durability.

How much cash did Pyxis (PYXS) raise from the royalty sale and how long will runway last?

Pyxis received a $11 million one-time payment and expects cash runway into the fourth quarter of 2026.

Were there any treatment-related deaths or severe ADC payload toxicities reported for MICVO?

No Grade 5 events occurred and no Grade 4 ADC payload TRAEs of interest were reported.

Did the MICVO monotherapy study identify any dosing or tolerability concerns for PYXS investors?

Monotherapy saw Grade ≥3 TRAEs in 56% of patients and discontinuations in 28%, with discontinuations concentrated in patients classified as high bodyweight.