# EDGAR Filing Document

**Accession Number:** 0001865494
**File Stem:** 0001193125-25-285282
**Filing Date:** 2025-11
**Character Count:** 31481
**Document Hash:** 2ba42cf2c8da995bb223261284e3bdc0
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-285282.hdr.sgml**: 20251118

**ACCESSION NUMBER**: 0001193125-25-285282

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 41

**CONFORMED PERIOD OF REPORT**: 20251118

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251118

**DATE AS OF CHANGE**: 20251118

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** IO Biotech, Inc.
- **CENTRAL INDEX KEY:** 0001865494
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 870909276
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41008
- **FILM NUMBER:** 251492760

**BUSINESS ADDRESS:**
- **STREET 1:** OLE MAALOES VEH 3
- **CITY:** COPENHAGEN
- **STATE:** G7
- **ZIP:** 2200
- **BUSINESS PHONE:** 4570702980

**MAIL ADDRESS:**
- **STREET 1:** OLE MAALOES VEH 3
- **CITY:** COPENHAGEN
- **STATE:** G7
- **ZIP:** 2200

?xml version='1.0' encoding='ASCII'? 8-K

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### WASHINGTON, D.C. 20549

### FORM 8-K

#### CURRENT REPORT

#### PURSUANT TO SECTION 13 OR 15(D)

#### OF THE SECURITIES EXCHANGE ACT OF 1934

#### Date of Report (Date of earliest event reported): November 18, 2025

## IO BIOTECH, INC.

#### (Exact name of Registrant as Specified in its Charter)

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| | | |
|:---|:---|:---|
| **Delaware** | **001-41008** | **87-0909276** |
| **(State or other jurisdiction**<br> **of incorporation)** | **(Commission**<br> **File Number)** | **(IRS Employer**<br> **Identification No.)** |

---

#### Ole Maaløes Vej 3

#### DK-2200 Copenhagen N

#### Denmark

#### (Address of principal executive offices) (Zip Code)

#### Registrant's telephone number, including area code: +45 7070 2980

#### N/A

#### (Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (<u>see</u> General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading<br>Symbol(s)** | **Name of each exchange**<br> **on which registered** |
| Common Stock, par value $0.001 per share | IOBT | The Nasdaq Stock Market LLC |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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| | |
|:---|:---|
| **Item 7.01.** | **Regulation FD Disclosure.**  |

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Beginning on November 18, 2025, IO Biotech, Inc., a Delaware corporation (the "Company") will participate in the Jefferies Global Healthcare Conference (the "Conference"). The Company has updated the corporate presentation that it intends to use at the Conference and in meetings with investors, a copy of which was posted to the Company's website on November 18, 2025 (the "Investor Deck").

A copy of the Investor Deck is attached hereto as Exhibit 99.1 and is incorporated by reference herein.

The information contained in this Current Report on Form 8-K, including Exhibit 99.1, is being furnished and shall not be deemed to be "filed" for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

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| | |
|:---|:---|
| **Item 9.01** | **Financial Statements and Exhibits.**  |

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(d) Exhibits

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| | |
|:---|:---|
| **Exhibit**<br> **Number** | **Exhibit Description** |
| 99.1 | [IO Biotech, Inc., Investor Deck, dated as of November 18, 2025](d59895dex991.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |

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#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | |
|:---|:---|:---|
|  | **IO BIOTECH, INC.** | **IO BIOTECH, INC.** |
| Date: November 18, 2025 | By: | /s/ Mai-Britt Zocca, Ph.D. |
|  | Name: | Mai-Britt Zocca, Ph.D. |
|  | Title: | Chief Executive Officer |

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## Exhibit 99.1

![Slide 1](g59895ex99_1s1g1.jpg)

Breaking Boundaries. Igniting Change. Nasdaq: IOBT Jefferies Healthcare Conference November 2025 Exhibit 99.1

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![Slide 2](g59895ex99_1s2g1.jpg)

DISCLAIMER \| Forward Looking Statements Certain information contained in this presentation includes "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, related to our business plan, clinical trials and regulatory submissions. We may, in some cases, use terms such as "may," "should," "would," "expects," "plans," "anticipates," "could," "intends," "target," "projects," "contemplates," "believes," "estimates," "predicts," "potential" or "continue" or other words that convey uncertainty of the future events or outcomes to identify these forward-looking statements. Our forward-looking statements are based on current beliefs and expectations of our management team that involve risks, potential changes in circumstances, assumptions, and uncertainties. Any or all of the forward-looking statements may turn out to be wrong or be affected by inaccurate assumptions we might make or by known or unknown risks and uncertainties. These forward-looking statements are subject to risks and uncertainties including risks related to the execution of our business plan, success and timing of our clinical trials or other studies and the other risks set forth in our filings with the U.S. Securities and Exchange Commission. For all these reasons, actual results and developments could be materially different from those expressed in or implied by our forward-looking statements. You are cautioned not to place undue reliance on these forward-looking statements, which are made only as of the date of this presentation. We undertake no obligation to publicly update such forward-looking statements to reflect subsequent events or circumstances, except as required by law.

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![Slide 3](g59895ex99_1s3g1.jpg)

Cylembio is an investigational drug candidate that has not been approved for marketing by the US FDA or other regulatory authorities.

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![Slide 4](g59895ex99_1s4g1.jpg)

IO Biotech \| Breaking boundaries. Igniting change PHASE 3 RESULTS \*Statistical significance threshold for this study was p≤0.045. 1. https://gco.iarc.fr/today/en/; 2. https://seer.cancer.gov/statfacts/html/melan.html; 3. Melanoma Research Alliance; 4. Larkin et al. N Engl J Med 2019;381:1535-1546; 5. Robert et al. Lancet Oncol 2019;20:1239-1251; 6. Tawbi et al. N Engl J Med 2022;386:24-34; 7. Weber et al. Oncologist. 2016;21(10):1230-1240; 8. Evaluate Pharma 2025 Cylembio is an ideal combination partner… …potential for clinical improvement across a number of combination agents without additional systemic toxicity PLATFORM POTENTIAL OPPORTUNITY Improved clinical effect observed without significant added systemic toxicity vs. pembro alone 19.4 vs. 11.0 Months mPFS HR=0.77 (CI 0.58-1.00) (p=0.056)\* PFS improvement observed across virtually all subgroups & stratification factors Demonstrated clinical improvement; Narrow miss on statistical significance Potential broad application… … with data across 3 indications (Melanoma, SCCHN, NSCLC), and pipeline potentially addressing other difficult-to-treat cancers of patients progress within one year of treatment: novel combinations are needed to improve patient outcomes 50% 15,000 US patients with advanced melanoma $5.6 billion US market opportunity growing at 9% Plan to align on new phase 3 design with FDA & discuss submission of MAAs based on IOB-013 data with EMA 2025

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![Slide 5](g59895ex99_1s5g1.jpg)

1. Melanoma of the Skin — Cancer Stat Facts; 2. https://seer.cancer.gov/statfacts/html/melan.html; Bajaj. J Natl Cancer Inst. 2020; Leeneman. EJC. 2021; Zhang. Adv Ther. 2023; Eggermont. J of Clin Onc. 2019; Eggermont. NEJM. 2022; Wolchok. J Clin Oncol. 2022; Miller, CA Cancer J Clin, 2019; National Comprehensive Cancer Network (NCCN): Clinical Practice Guidelines in Oncology (NCCN Guidelines®); Melanoma Version 2.2025 THE MELANOMA PATIENT JOURNEY 1 Disease Presentation Primary Care Physician or Dermatologist 2 Diagnosis & Referral Newly Diagnosed Melanoma in ~100, 0001 patients annually in the U.S. 3 Resectable Melanoma ~92,000 patients2 Surgical candidate? Residual Disease Post-Surgery? Neo/adjuvant treatment and Surgical Resection 4 Unresectable or Metastatic Melanoma ~15,000 patients2: High unmet medical need still exists due to lack of efficacy and toxicity issues from available SOC 1L Treatment Selection, Insurance and Access (anti-PD1 monotherapy; anti PD1 combination with either anti-CTLA4 or anti LAG3 agents) Patient Checks in at the Infusion Center Product Preparation & Delivery to Infusion Center Product Administration Yes No Yes Cylembio has potential to address a high unmet medical need by improving clinical effect without adding systemic toxicity

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![Slide 6](g59895ex99_1s6g1.jpg)

Cylembio in First-Line Advanced Melanoma

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![Slide 7](g59895ex99_1s7g1.jpg)

Primary endpoint PFS by central review Secondary/exploratory endpoints ORR, DRR, CRR, OS, DoR, TTR, DCR Incidence of AEs and SAEs Quality of life Biomarkers in blood and tumor tissue will also be assessed Stratification Endpoints Randomization 407 enrolled across >100 sites in Europe, Australia, South Africa, Israel and the US Advanced melanoma Unresectable stage III Metastatic stage IV > 6 months after neoadjuvant/ adjuvant anti-PD-1 Measurable disease (RECIST 1.1) ECOG performance status 0-1 Stable CNS disease is allowed Eligibility criteria 1L, first-line; AE, adverse event; BLA, Biologics License Application; CNS, central nervous system; CRR, complete response rate; DCR, disease control rate; DoR, duration of response; DRR, durable response rate; ECOG, Eastern Cooperative Oncology Group; IA, interim analysis; IDMC, independent data monitoring committee; mut, mutation; ORR, objective response rate; OS, overall survival; PD-1, programmed cell death protein 1; PFS, progression-free survival; ph, phase; q3w, once every 3 weeks; RECIST, Response Evaluation Criteria in Solid Tumors; SAE, serious adverse event; TTR, time to response; WT, wild-type. ClinicalTrials.gov: NCT05155254. Disease Stage (Low vs high risk)\* BRAF (mut vs WT) \*Stage III and IV M1a-b vs. stage IV M1c-d IO102-IO103 and Pembrolizumab 200mg q3w N= 203 Pembrolizumab 200mg q3w N=204 1:1 Clinical trial design Patients in both arms can be treated for up to 2 years IOB-013 CLINICAL TRIAL DESIGN \| Phase 3 Advanced Melanoma Clinical Trial Design

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![Slide 8](g59895ex99_1s8g1.jpg)

PHASE 3 TRIAL \| Cylembio demonstrated PFS improvement across virtually all pre-specified subgroups and stratification factors Topline results released August 2025 \*Statistical significance threshold for this study was p≤0.045. \*\*Post-hoc analysis. Source: Data on file. Overall Survival trend favoring Cylembio combination arm, OS not yet mature HR = 0.79 (CI 0.57, 1.10); Well-tolerated with no significant added systemic toxicity compared to pembrolizumab alone Median progression free survival, ITT analysis: Cylembio plus pembrolizumab 19.4 months vs. 11.0 months for patients treated with pembrolizumab alone, HR=0.77 (CI 0.58-1.00) (p=0.056)\* In PD-L1 negative group, mPFS was 16.6 months in patients treated with Cylembio plus pembrolizumab compared to 3.0 months in patients treated with pembro alone, HR: 0.54 (CI 0.35-0.85) (nominal p=0.006) Excluding patients with prior anti-PD1 exposure\*\* (n=36): mPFS was 24.8 months vs. 11.0 months HR: 0.74 (CI 0.56-0.98) (nominal p=0.037) (n=371)

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![Slide 9](g59895ex99_1s9g1.jpg)

PHASE 3 TRIAL \| Early Separation of PFS Curves at 3 Months – Widening Over Time Source: Company data on file. Kaplan-Meier estimate of PFS in ITT determined by BICR per RECISTv1.1 and stratified by PD-L1 status and disease stage

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![Slide 10](g59895ex99_1s10g1.jpg)

PHASE 3 TRIAL \| Trend in Overall Survival Benefiting Cylembio (not yet mature) separating early and widening HR, 0.79; 95% CI, 0.57 to 1.10 OS not mature HR 0.79 is in line with 12 month OS data reported from other IO combinations Source: Company data on file. Kaplan–Meier estimate of OS in ITT and stratified by PD-L1 status and disease stage Key takeaways

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![Slide 11](g59895ex99_1s11g1.jpg)

SAFETY DATA \| Treatment with Cylembio did not add significant systemic toxicity compared to patients treated with pembrolizumab monotherapy Source: Company data on file. Acronyms: AE, adverse event; CTCAE, common terminology criteria for adverse events; MedDRA, medical dictionary for medical regulatory activities; N, number. IO102-IO103 plus pembrolizumab, N=200 Pembrolizumab, N=198 Any grade, n (%) Grade 3–4, n (%) Any grade, n (%) Grade 3–4, n (%) Any AEs\* 194 (97.0) 75 (37.5) 187 (94.4) 69 (34.8) AE leading to discontinuation of study treatment 31 (15.5) 15 (7.5) 31 (15.7) 13 (6.6) Serious AEs 64 (32.0) 44 (22.0) 64 (32.3) 39 (19.7) Treatment-related AEs 171 (85.5) 29 (14.5) 161 (81.3) 31 (15.6) Treatment-related serious AE 19 (9.5) 13 (6.5) 25 (12.6) 15 (7.6) Immune-mediated AEs 68 (34.0) 17 (8.5) 76 (38.4) 18 (9.1) Investigator assessed immune-related AE not included in the immune-mediated AE definition 102 (51.0) 13 (6.5) 99 (50.0) 15 (7.6) Injection-site reaction (grouped term) 112 (56.0) 1 (0.5) – – \*The AEs leading to death among patients who received IO102-IO103 plus pembrolizumab (n=4) or pembrolizumab (n=5) were considered not related to the study treatment by the investigators Safety analyses conducted on all randomized patients who received ≥1 dose of assigned trial medication; AEs classified by the MedDRA version 28.0 and graded by CTCAE version 5.0 Treatment-related AE: events possibly or probably related to either IO102-IO103 or Pembrolizumab Immune-mediated AE defined by KEYTRUDA adverse events of special interest list version 28.0 Immune-related events based on the investigator assessment

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![Slide 12](g59895ex99_1s12g1.jpg)

MARKET OPPORTUNITY IN ADVANCED MELANOMA \| Cylembio® profile has potential to fulfill significant unmet needs and drive market leadership 1. https://gco.iarc.fr/today/en/; 2. https://seer.cancer.gov/statfacts/html/melan.html; 3. Melanoma Research Alliance; 4. Larkin et al. N Engl J Med 2019;381:1535-1546; 5. Robert et al. Lancet Oncol 2019;20:1239-1251; 6. Tawbi et al. N Engl J Med 2022;386:24-34; 7. Weber et al. Oncologist. 2016;21(10):1230-1240; 8. Evaluate Pharma 2025 Melanoma incidence is increasing1-3 ~331,000 patients newly diagnosed annually (global) ~58,000 patient deaths annually (global) 30% 5-year survival rate for patients in stage IV Cylembio® profile has potential to drive market leadership8 2030 2024 14 12 10 8 6 4 2 +9% 13.2 9.4 Forecast global Melanoma Drug Sales in USD billions US CAGR Patients and physicians seek more effective treatment options4-7 ~50% of patients progress within one year of treatment; novel combinations are needed to improve patient outcomes

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![Slide 13](g59895ex99_1s13g1.jpg)

Cylembio is an ideal combination partner candidate that we believe could deliver clinical activity without tolerability issues: IO102-IO103 has demonstrated improvement in PFS, trend towards long and durable response including in hard-to-treat subgroups, with favorable safety across a number of combination agents in clinical studies IO102-IO103 + nivolumab Clinically meaningful data in all patients, even those with poor prognostic factors Biomarkers linked to responding patients IO102-IO103 + pembrolizumab Clinically meaningful improvement in PFS across subgroups; narrow miss on statistical significance\* Early separation of PFS curves and durability Induction of T-cells; Dual seems to follow clinical response IO102-IO103 + nivolumab + relatlimab Three sites, enrollment completed Preliminary data as of Sept. 2025 shows early PFS trend suggestive of improved clinical activity vs. historic data with a-PD-1/ a-Lag-3 combination; PFS data (n=32) is not yet mature No new safety signal, safety profile consistent with a-PD-1/a-Lag-3 data IO102-IO103 + anti PD-1 + Lag-3 inhibitor Adaptive Ph3 study designed to be relevant for evolving/future landscape (SoC) Futility analysis to determine effect size & trial sample size Goal: Long/durable benefit across sub-groups including poor prognostic population, favorable safety profile MM1636 (n=30) IOB-023 – New Proposed Adaptive Ph3 study (n=550-800) IOB-013 (n=407) IIT (NCT05912244) (n=43) IO102-IO103 in 1L ADVANCED MELANOMA \| Cylembio is at the forefront of triplet combination therapy development \*Statistical significance threshold for this study was p≤0.045. Source: Data on file. Comparisons across clinical trials should be interpreted with caution. Differences in study design, patient populations, endpoints, and other factors limit the ability to draw direct or reliable conclusions between separate trials.

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![Slide 14](g59895ex99_1s14g1.jpg)

Primary endpoint PFS by central review Secondary/exploratory endpoints OS, DoR, TTR, DCR Incidence of AEs and SAEs Quality of life Biomarkers in blood and tumor tissue will also be assessed Stratification Endpoints Phase 2 (step 1) Randomization Advanced melanoma Unresectable stage III Metastatic stage IV Patients with acral or mucosal melanoma (TBD) Patients > 6 months after neoadjuvant/ adjuvant anti-PD-1 (TBD) Measurable disease (RECIST 1.1) ECOG performance status 0-1 Stable CNS disease is allowed Eligibility criteria 1L, first-line; AE, adverse event; BLA, Biologics License Application; CNS, central nervous system; CRR, complete response rate; DCR, disease control rate; DoR, duration of response; DRR, durable response rate; ECOG, Eastern Cooperative Oncology Group; IA, interim analysis; IDMC, independent data monitoring committee; mut, mutation; ORR, objective response rate; OS, overall survival; PD-1, programmed cell death protein 1; PFS, progression-free survival; ph, phase; q3w, once every 3 weeks; RECIST, Response Evaluation Criteria in Solid Tumors; SAE, serious adverse event; TTR, time to response; WT, wild-type. ClinicalTrials.gov: NCT05155254. \*Stage III and IV M1a-b vs. stage IV M1c-d IO102-IO103 and aPD-1+LAG-3 inhibitor N=200 aPD-1+LAG-3 inhibitor N=200 PD-L1 status Prior aPD1/aPD-L1 exposure 1:1 PROPOSED IOB-023 ADAPTIVE PHASE 3 CLINICAL TRIAL DESIGN \| Leading the future triplet treatment landscape in 1L advanced melanoma @ ~150 PFS events Size of second phase to be determined by observed HR Will also include a futility assessment Sample Size Re-estimation (expected mid 2028) Continue Enrolling Phase 3 (step 2) IO102-IO103 and aPD-1+LAG-3 inhibitor N= up to 200 additional aPD-1+LAG-3 inhibitor N= up to 200 additional 1:1 Proposed IOB-023 Clinical Trial Design Trial Initiation Subject to Raising Additional Capital

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![Slide 15](g59895ex99_1s15g1.jpg)

Our Pipeline: NSCLC, SCCHN, Neoadjuvant/adjuvant

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![Slide 16](g59895ex99_1s16g1.jpg)

Product candidates Line of therapy/ indication Pre-clinical Phase 1 Phase 2 Phase 3 Takeaways & next steps Cylembio® IO102-IO103 Targets: IDO1, PD-L1 IOB-013, IOB-023: First Line Advanced Melanoma\* Cylembio demonstrated clinical improvement in PFS, narrowly missed statistical significance in IOB-013 Potential to discuss MAA submissions based on IOB-013 with EU regulators Plan to align on IOB-023 trial design with FDA IO102–IO103 IOB-022: First Line Solid Tumors\* Lung (NSCLC) Head & Neck (SCCHN) SCCHN: Primary endpoint met NSCLC: Encouraging data IOB-032: Neoadjuvant / Adjuvant Solid Tumors\* Melanoma Head & Neck (SCCHN) Enrollment completed in January 2025 Initial data available 2H25; presented in 2026 IO112 Target: Arginase 1 Solid Tumors Indications TBD Next pipeline candidate expected to enter clinical development IO170 Target: TGFb Solid Tumors Indications TBD Early-stage pipeline candidate PIPELINE \| 3 T-win product candidates being evaluated in multiple cancer indications Cylembio® (imsapepimut and etimupepimut, adjuvanted) \* In combination with pembrolizumab; NSCLC, non-small cell lung cancer, PFS, progression-free survival; SCCHN, squamous cell carcinoma of the head and neck; IOB-013: ClinicalTrials.gov: NCT05155254; IOB-022: ClinicalTrials.gov: NCT05077709; IOB-032: ClinicalTrials.gov: NCT05280314 IOB-013 IOB-023 – proposed seamless phase 2/3

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![Slide 17](g59895ex99_1s17g1.jpg)

FIRST-LINE METASTATIC NSCLC Results from Phase 2 (SITC 2024) ORR 55% unconfirmed/48% confirmed; mPFS 8.1 months Benchmark\*\* ORR 39%, mPFS 6.5 months Status Encouraging ORR and PFS and no progression in nearly half of patients FIRST-LINE RECURRENT/ METASTATIC SCCHN Results from Phase 2 (ESMO 2024) ORR 44.4%; mPFS 6.6 months Irrespective of HPV status Benchmark\*\* ORR 23%, mPFS 3.4 months Status Primary endpoint ORR met with encouraging PFS FIRST-LINE ADVANCED MELANOMA Results from Phase 3 (IOB-013): 19.4 months mPFS; HR=0.77 (CI 0.58-1.00) (p=0.056)\*; narrow miss on statistical significance; demonstrated clinical improvement observed across virtually all subgroups & stratification factors; Next Steps: Plan to align on new phase 3 design with FDA & discuss submission of MAAs based on IOB-013 data with EMA TOTALITY OF CLINICAL DATA IS COMPELLING \| Clinical meaningful activity demonstrated across three indications …expanding the body of evidence across three indications and settings \*Statistical significance threshold for this study was p≤0.045; \*\* KEYNOTE-048 (pembro alone in 1L SCCHN PD-L1 CPS ≥20%): ORR 23%; KEYNOTE-042 (pembro alone in 1L NSCLC PD-L1 TPS ≥50%): ORR 39%; 1. Kjeldsen JW, et al. Nat Med 2021;27:2212–23. Erratum in: Nat Med 2022;28:871; 2. Lorentzen CL, et al. J Immunother Cancer 2023;11:e006755; 3. ClinicalTrials.gov: NCT05155254; 4. Riess JW, et al. Presented at ESMO 2024. Poster 1022P; 5. Riess JW, et al. Presented at STIC 2024. Poster 756 Starting with advanced melanoma…

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![Slide 18](g59895ex99_1s18g1.jpg)

ADDRESSABLE PATIENTS \| Cylembio with potential to redefine treatment of hard-to-treat solid tumors and expanding beyond 1L advanced melanoma Total addressable patients (US) >100,000 patients1 ~40,000 patients2 ~15,000 patients3 Expand to earlier lines 3 Peri-operative SCCHN Peri-operative melanoma Advance to other hard-to-treat tumors 2 1L metastatic NSCLC 1L advanced SCCHN Anchor in 1L advanced melanoma 1 1. 2025 estimated incidence of resectable Melanoma and SCCHN patients in the US . SEER; For melanoma refer to references in footnote #3; Ko C, Citrin D. Radiotherapy for the management of locally advanced squamous cell carcinoma of the head and neck. Oral Dis. 2009 Mar;15(2):121-32.) 2. 2023 estimated 1L mSCCHN CPS>20 patients in the US. SEER; Bhat. Adv Cancer Res. 2021; Fakhry. ACS Journals, 2018; Gallo Cancers, 2023 special issue; Placa J of Cancer Treatment and Diagnosis, 2021; Barsouk. Med Sci. 2023; Cramer. Oral Oncol. 2019; Siegel. CA Cancer J Clin. 2023; Wusiman. Pathol Res Prac. 2022; estimated 1L addressable mNSCLC PD-L1≥50%: SEER; American Cancer Society; Mack Cancer, 2020; Evans Pathology and Oncology Research, 2018; Ganti. JAMA. 2021; Rodak. Cancers. 2021; ASCO; GlobalData; NCI; Karacz. Clin Lung Cancer. 2019; Shah. Cancer Treatment and Research Communications. 2023; Herbst. Lancet. 2016; 3. 2025 estimated addressable 1L advanced melanoma patients in the US. SEER Melanoma of the Skin; Bajaj. J Natl Cancer Inst. 2020; Bensimon. J Med Econ. 2019; Leeneman. EJC. 2021; Luke. ASCO Presentation. 2023; Zhang. Adv Ther. 2023; Eggermont. J of Clin Onc. 2019; Eggermont. NEJM. 2022

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![Slide 19](g59895ex99_1s19g1.jpg)

PLATFORM POTENTIAL \| The proposed adaptive Phase 3 trial aims to give IOBT the potential to jump ahead with the goal of becoming the first triple combination therapy New proposed Phase 3 study (IOB-023) Designed to be well positioned in evolving/future landscape (SoC) Goal is to demonstrate long/durable benefit across sub-groups including poor prognostic population, favorable safety profile Future 2026 - 2029 Broadly applicable platform Potential for multiple cancer indications and novel combination strategies for treatment Potential use of the T-Win technology into other types of diseases, such as infectious, inflammatory, and auto-immune diseases Expand the T-win platform in 3 dimensions Immune-modulating cancer vaccine targeting both the tumor and the immune suppressive cells Randomized data confirming activity in patients with advanced melanoma; POC established in NSCLC and SCCHN 2022 - 2025 Validated platform with compelling clinical data Positioning Cylembio as the leading combination partner

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![Slide 20](g59895ex99_1s20g1.jpg)

T-win platform can be used outside oncology with opportunity to investigate infectious diseases Two preclinical programs in solid tumors showing evidence of anti-tumor activity as monotherapy or in combination PRE-CLINICAL PIPELINE \| Expanding the clinical portfolio with Arginase 1 program; IND filing expected in 2026 Pre-clinical pipeline opportunities IO112 Target Arg 1 IO170 Target TGFβ TGFβ inhibits tumor growth in animal models The novel approach to TGFβ+ cells provides opportunities in oncology and fibrotic diseases T-win applications outside IO (future potential) Arginase 1 vaccine candidate controls tumor growth in animal models via direct targeting of Arg1+ cells (both tumor and myeloid cells) IND planned in 2026

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Our T-win® Platform

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![Slide 22](g59895ex99_1s22g1.jpg)

MECHANISM OF ACTION \| IO Biotech's T-win® vaccine approach supported by improvement in PFS demonstrated with Cylembio in IOB-013\* Subcutaneous injection with T-win® therapeutic cancer vaccine T-win vaccine activates T cells with a dual mechanism of action T cells attack both target expressing tumor cells and immune-suppressive cells (e.g., IDO1, PD-L1) The modulated and inflamed TME becomes immune permissive, enabling further tumor cell killing by the T cells IO Biotech's T-win cancer vaccine platform is designed to provide a new therapeutic strategy with the potential to improve outcomes for patients with cancer by killing tumor cells and turning the tumor micro-environment hostile to cancer cells \*Narrowly missed on statistical significance Kjeldsen JW, et al. Nat Med 2021;27:2212–23. Erratum in: Nat Med 2022;28:871; Munir S, et al. PLoS One 2012;7:e34568; Munir S, et al. Oncoimmunology 2013;2:e23991; Ahmad SM, et al. Blood Cancer J 2014;4:e230; Andersen MH. Semin Immunopathol 2019;41:87–95; IO Biotech and Lankenau Institute (unpublished data); Andersen MH, et al. Semin Immunopathol 2023;45:253–64.

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![Slide 23](g59895ex99_1s23g1.jpg)

OFF-THE-SHELF TREATMENT \| Cylembio is designed to ensure patients access to treatment without delay\* \* Compared to a personalized vaccine \*\* E.g., anti PD-1 treatment Characteristics of an off-the-shelf vaccine enhancing patients and physicians' experience Directly available… at site of care, in both community and academic settings Rapid administration… subcutaneous administration along with combination agent with no additional visits required\*\* Fast access… to the medicine ensuring patients do not have to wait\* Convenient storage… as the vaccine can be stored at 2-8°C until administration Picture for illustrative purposes only

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Outlook

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MILESTONES \| Several important milestones expected through 2026 Cylembio \| 1L Advanced Melanoma Top-line readout of primary endpoint in phase 3 study, 3Q25, narrowly missed statistical significance Enrollment completed in January 2025 Initial data from neoadjuvant/adjuvant Ph2 available 2H25; presented in 2026 Complete enrollment in neoadj/adj Ph2 cohorts Enrollment completed in January 2025 Initial data from neoadjuvant/adjuvant Ph2 available 2H25; presented in 2026 Complete enrollment in neoadj/adj Ph2 cohort IND enabling studies H1 2025 H2 2025 Continue readiness for IND submission Cylembio \| Neoadjuvant / adjuvant Melanoma Cylembio \| 1L Lung (NSCLC) Cylembio \| Head & Neck (SCCHN) IO112 \| Solid Tumors (pre-clinical) IO170 \| Solid Tumors (pre-clinical) Final data from Ph2 BLA, biologics license application; IND, investigational new drug; NSCLC, non-small cell lung cancer; SCCHN, squamous cell carcinoma of the head and neck Potentially initiate new phase 3 study Potential EU MAA submissions based on IOB-013 data 2026 IND submission Additional data Cash through 1Q2026 with 3Q cash balance of ~$31M\* \* On May 6, 2025, the Company drew on the EIB tranche A loan facility and obtained funding in the principal amount of €10.0 million and on July 4, 2025, the Company drew the second tranche of the EIB loan facility and obtained €12.5 million, before payment of certain fees and transaction related expenses; in 3Q 25, the Company sold ~$$6.6 million, after deducting fees and expenses, through an ATM facility

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IO Biotech Team

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THE TEAM \| We have a strong management team with large biopharma and biotech experience Mai-Britt Zocca, PhD President and Chief Executive Officer Amy Sullivan, MBA Chief Financial Officer Dan Mannix, PhD SVP Regulatory Devin Smith General Counsel Qasim Ahmad, MD Chief Medical Officer Faiçal Miyara, PhD Chief Business Officer Eric Faulkner, MBA Chief Technical Officer Marjan Shamsaei, PharmD SVP Commercial

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THE TEAM \| Our management team is supported by the Board of Directors and the Scientific Advisory Board Peter Hirth, Ph.D. Chairman Kathleen Sereda Glaub, M.B.A. Member Christian Elling, Ph.D. Member – Lundbeckfonden Heidi Hunter Member David V. Smith, M.B.A. Member Mai-Britt Zocca, Ph.D. Founder, President and CEO Inge Marie Svane, M.D., Ph.D. Co-founder, Clinical Advisor Alexander Eggermont, M.D., Ph.D. Sr. Clinical Advisor Kapil Dhingra, M.D. Strategic R&D Advisor Mads Hald Andersen, DMSc., Ph.D. Co-founder, Scientific Advisor Helen Collins, M.D. Member Board of Directors Scientific Advisory Board