# EDGAR Filing Document

**Accession Number:** 0001776111
**File Stem:** 0000950170-25-083447
**Filing Date:** 2025-6
**Character Count:** 33112
**Document Hash:** 169e9fc7776986ed4c69ffd4aefaf62c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950170-25-083447.hdr.sgml**: 20250609

**ACCESSION NUMBER**: 0000950170-25-083447

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 48

**CONFORMED PERIOD OF REPORT**: 20250609

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20250609

**DATE AS OF CHANGE**: 20250609

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MBX Biosciences, Inc.
- **CENTRAL INDEX KEY:** 0001776111
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42272
- **FILM NUMBER:** 251032857

**BUSINESS ADDRESS:**
- **STREET 1:** 11711 N. MERIDIAN STREET
- **STREET 2:** SUITE 300
- **CITY:** CARMEL
- **STATE:** IN
- **ZIP:** 46032
- **BUSINESS PHONE:** 3179893100

**MAIL ADDRESS:**
- **STREET 1:** 11711 N. MERIDIAN STREET
- **STREET 2:** SUITE 300
- **CITY:** CARMEL
- **STATE:** IN
- **ZIP:** 46032

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

**UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549**

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## **FORM** 8-K

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**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported):** June 09, 2025<br>

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MBX Biosciences, Inc.

**(Exact name of Registrant as Specified in Its Charter)**

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| | | |
|:---|:---|:---|
| Delaware | 001-42272 | 84-1882872 |
| **(State or Other Jurisdiction<br>of Incorporation)** | **(Commission File Number)** | **(IRS Employer<br>Identification No.)** |
| 11711 N. Meridian Street<br>Suite 300 |  |  |
| Carmel**,** Indiana |  | 46032 |
| **(Address of Principal Executive Offices)** |  | **(Zip Code)** |

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**Registrant's Telephone Number, Including Area Code:** (317) 659-0200<br>

Not Applicable

**(Former Name or Former Address, if Changed Since Last Report)**

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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:

☐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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| | | |
|:---|:---|:---|
| **<br>Title of each class** | **Trading<br>Symbol(s)** | **<br>Name of each exchange on which registered** |
| Common Stock, $0.0001 par value per share | MBX | Nasdaq Global Select Market |

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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** 
On June 9, 2025, MBX Biosciences, Inc. posted to the "Investors" section of the Company's website at *www.mbxbio.com* an updated corporate presentation. A copy of the Corporate Presentation is attached hereto as Exhibit 99.1 and is incorporated by reference into this Item 7.01 of this Current Report on Form 8-K.

The information contained in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed "filed" for purposes of the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

## **Item 9.01 Financial Statements and Exhibits.** 
***(d) Exhibits***

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| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 99.1 | [<u>Corporate Presentation dated June 9, 2025</u>](mbx-ex99_1.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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| | | | |
|:---|:---|:---|:---|
|  |  |  | MBX Biosciences, Inc. |
| Date: | June 9, 2025 | By:  | /s/ P. Kent Hawryluk |
|  |  |  | President and Chief Executive Officer (Principal Executive Officer) |

---

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## Exhibit 99.1

![Slide 1](mbx-ex99_1s1.jpg)

Precision Endocrine Peptides™ Company Overview June 2025 Exhibit 99.1

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![Slide 2](mbx-ex99_1s2.jpg)

Disclaimer This presentation includes forward looking statements. All statements other than statements of historical facts contained in this presentation, including statements regarding our product candidates, preclinical study and/or clinical trial timelines, including projected data announcements, future results of operations and financial position, strategy and plans, industry environment, potential growth opportunities, and our expectations for future operations, are forward looking statements The words " believe," " may," "will," " estimate," " continue," " anticipate," " design," " " expect," " could," " plan," " potential," " predict," " seek," " should," "would," or the negative version of these words and similar expressions are intended to identify forward looking statements. We have based these forward-looking statements on our current expectations and projections about future events and trends that we believe may affect our financial condition, results of operations, strategy, short- and long-term business operations and objectives, and financial needs. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including but not limited to, our ability to develop and advance our programs and product candidates, our regulatory approvals and filings, and other risks, uncertainties and assumptions identified in our filings with the Securities and Exchange Commission. Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time, and it is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this presentation may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements. You should not rely upon forward looking statements as predictions of future events. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee that the future results, levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or occur. Moreover, except as required by law, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this presentation to conform these statements to actual results or to changes in our expectations, unless required by law. This presentation contains estimates and other information concerning our industry, our business and the markets for our product candidates. Information that is based on estimates, market research or similar methodologies, including prevalence studies which are extrapolated to broader populations, is inherently subject to uncertainties, and actual events or circumstances may differ materially from events and circumstances that are assumed in this information. Unless otherwise expressly stated, we obtained this industry, business, market and other data from our own internal estimates and research as well as from reports, research surveys, studies and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data and similar sources. Industry publications and surveys generally state that the information contained therein has been obtained from sources believed to be reliable. Although we believe the industry and market data to be reliable as of the date of this presentation, this information could prove to be inaccurate. Industry and market data could be wrong because of the method by which sources obtained their data and because information cannot always be verified with complete certainty due to the limits on the availability and reliability of raw data, the voluntary nature of the data gathering process and other limitations and uncertainties. While we are responsible for the accuracy of such information and believe our internal company research as to such matters is reliable and the market definitions are appropriate, neither such research nor these definitions have been verified by any independent source.

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![Slide 3](mbx-ex99_1s3.jpg)

Pioneering Precision Peptides for Endocrine and Metabolic Diseases Developing treatments to improve clinical outcomes and simplify disease management Canvuparatide (MBX 2109) for Hypoparathyroidism (HP): PTH peptide prodrug with FDA Orphan Drug Designation Designed to deliver continuous, infusion-like exposure to PTH and convenient weekly dosing MBX 1416 for Post-bariatric Hypoglycemia (PBH): long-acting GLP-1 receptor antagonist Designed to prevent severe hypoglycemia and improve quality of life with convenient weekly dosing Two rare endocrine programs in clinical development MBX 4291 for obesity: GLP-1/GIP receptor co-agonist prodrug with potential for monthly dosing IND-enabling studies complete; IND submission anticipated in Q2 2025 Potential for less frequent dosing, improved GI tolerability and increased weight loss as demonstrated in preclinical models Multiple additional programs: in lead optimization stage of development for obesity and co-morbidities Differentiated obesity portfolio >$400 million raised to date from leading healthcare investors ~$240 million in cash as of March 31, 20251; expected to support operations into mid-2027 Strong financial position Founded by global leaders in peptide drug design, development and commercialization Precision therapeutics with optimized pharmaceutical properties: extended duration of action, consistent drug exposures, less frequent dosing Proprietary Precision Endocrine Peptide™ (PEP™) Platform 1. Unaudited cash, cash equivalents and marketable securities

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![Slide 4](mbx-ex99_1s4.jpg)

MBX's World-class Leadership Team Kent HawrylukPRESIDENT & CEO Rick Bartram, CPACHIEF FINANCIAL OFFICER Mike Dorato, PhDSENIOR VICE PRESIDENT DISCOVERY & NONCLINCAL DEVELOPMENT Matt Gambino VICE PRESIDENT MARKETING Michelle GrahamCHIEF HUMAN RESOURCES OFFICER Sam Azoulay, MDCHIEF MEDICAL OFFICER Stewart Hallett VICE PRESIDENT CLINICAL OPERATIONS Elisa Fabbrini, MD, PhD VICE PRESIDENT CLINICAL DEVELOPMENT Mark Hope SENIOR VICE PRESIDENT REGULATORY & QUALITY Chatan Charan, PhD SENIOR VICE PRESIDENT PHARMACEUTICAL DEVELOPMENT & CMC

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![Slide 5](mbx-ex99_1s5.jpg)

Candidate MOA Indication Discovery IND Enabling Phase 1 Phase 2 Phase 3 Anticipated Milestones Endocrine Portfolio Canvuparatide (MBX 2109) PTH Prodrug Hypoparathyroidism Hypo-parathyroidism Phase 2 topline results in Q3 2025 MBX 1416 GLP-1 Receptor Antagonist Post-Bariatric Hypoglycemia Post-bariatric Hypoglycemia Phase 2 initiation in 2H 2025 Obesity Portfolio MBX 4291 GLP-1/GIP Co-agonist Prodrug Obesity & co-morbidities Obesity & co-morbidities IND submission in Q2 2025 Expanding a Pipeline of PEPs in Significant Rare Disease and Obesity Markets MBX retains global commercial rights to all programs GLP-1=glucagon-like peptide-1; GIP=glucose-dependent insulinotropic polypeptide; PTH=parathyroid hormone Beyond MBX 4291, we have a robust discovery pipeline including multiple obesity programs in the lead optimization stage of development.

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![Slide 6](mbx-ex99_1s6.jpg)

Precision Endocrine Peptide™ (PEP™) Platform Proprietary tools and know-how with the potential to enable design and development of transformative peptide therapeutics INNOVATIVE PEPTIDE DESIGN Designed to precisely time chemical conversion of prodrug to active drug to reduce peak-to-trough ratios and improve clinical outcomes With a goal to provide: Enhanced physical properties including stability and solubility Increased potency Multiple mechanisms of action in a single peptide PROGRAMMABLE PRODRUG Fatty Acylation Aims to provide: Increased duration of action (convenient dosing regimen) Compatibility with non-injectable formulations (e.g. oral)

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![Slide 7](mbx-ex99_1s7.jpg)

Canvuparatide (MBX 2109) Investigational Once-Weekly PTH Replacement Therapy for Hypoparathyroidism

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![Slide 8](mbx-ex99_1s8.jpg)

Canvuparatide for Hypoparathyroidism – A Serious Endocrine Disease Estimated >250,000 patients in U.S. and EU combined1,2 PTH=parathyroid hormone 1. Clarke B et al JCEM 2016, 2. Powers J et al JBMR 2013, 3. Khan A et al JBMR 2022, 4. Yao L et al Complications Symptoms JBMR 2022 Hypocalcemia: Tetany, muscle cramping/spasms/twitching, numbness, tingling, seizures Cognition: Cognitive impairment, confusion Hypercalcemia: Polyuria, nausea, vomiting, constipation, weakness Deficiency in parathyroid hormone (PTH) Etiology: Inadvertent removal of parathyroid during thyroid surgery and less commonly due to autoimmune disease and genetic disorders Renal: Kidney stones, chronic kidney disease, nephrocalcinosis Cardiovascular: Arrythmias, ischemic heart disease Depression / Infections CAUSE SYMPTOMS3,4 COMPLICATIONS3,4

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![Slide 9](mbx-ex99_1s9.jpg)

Managing Hypoparathyroidism: PTH Replacement Aims to Address Shortcomings of Standard of Care PTH=parathyroid hormone; QoL=quality of life 1. Khan A et al. JBMR 2022 Calcium and active vitamin D1 supplementation Daily PTH replacement therapy Investigational once-weekly PTH replacement therapy STANDARD OF CARE Does not address underlying pathophysiology Significant pill burden Serum calcium fluctuations Contributes to renal complications YORVIPATH® (palopegteriparatide) Approved in U.S. and E.U. for the treatment of hypoparathyroidism in adults Eneboparatide In Phase 3 development Designed to: Lower daily peak-to-trough PTH exposures vs. daily injectables Normalize serum and renal calcium Eliminate pill burden Convenient weekly dosing Improve QoL Reduce complications DAILY INJECTIONS Canvuparatide WEEKLY INJECTION

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![Slide 10](mbx-ex99_1s10.jpg)

Canvuparatide (MBX 2109): Prodrug Chemically Converts to Active Drug at a Precisely Controlled Rate Under Physiologic Conditions PTH=parathyroid hormone Biologically active peptide analog is converted and inactive metabolite eliminated Canvuparatide (MBX 2109) PRODRUG Dipeptide ACTIVE DRUG Fatty acids (FA) facilitate binding to albumin PTH Receptor FA Albumin FA facilitates extended time action Active drug binds to and activates the PTH receptor A B C

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![Slide 11](mbx-ex99_1s11.jpg)

Canvuparatide (MBX 2109) Phase 1 Trial SAD=single ascending dose; MAD=multiple ascending dose; SC=subcutaneous; QW=every week 1. ClinicalTrials.gov Identifier: NCT05158335 Single and multiple ascending doses of MBX 2109 in healthy adult subjects1 Endpoints Primary: Secondary: To evaluate safety and tolerability Pharmacokinetics (PK) profile of MBX 2109 prodrug and active drug Pharmacodynamic (PD) effects on albumin-adjusted serum calcium levels and suppression of endogenous PTH SAD (n=36) n=up to 8 subjects/cohort (2 placebo: 6 active) Placebo vs MBX 2109 SC 50-150-300-450-600 μg SC Key PD marker: Serum calcium MAD (n=40) n=10 subjects/cohort (2 placebo: 8 active) Placebo and MBX 2109 200-400-600-900 μg SC QW x 4 doses Key PD markers: Serum calcium and endogenous PTH (1-84)

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![Slide 12](mbx-ex99_1s12.jpg)

TEAEs by Preferred Term Reported in ≥5% Subjects Following Repeat Administration of Canvuparatide (MBX 2109) or Placebo n=number of subjects; TEAEs = treatment emergent adverse events MBX 2109 Preferred Term Placebo(N = 8)n (%) 200 µg (N = 8)n (%) 400 µg (N = 8)n (%) 600 µg (N = 8)n (%) 900 µg (N = 8)n (%) Overall(N = 40)n (%) Overall 2 (25.0%) 4 (50.0%) 4 (50.0%) 7 (87.5%) 5 (62.5%) 22 (55.0%) Injection site erythema --- --- 2 (25.0%) 2 (25.0%) 2 (25.0%) 6 (15.0%) SARS-CoV-2 test positive 1 (12.5%) --- 3 (37.5%) 1 (12.5%) --- 5 (12.5%) Constipation 1 (12.5%) --- --- --- 2 (25.0%) 3 (7.5%) Hypercalcemia --- --- --- 1 (12.5%) 2 (25.0%) 3 (7.5%) Arthralgia --- --- --- 2 (25.0%) --- 2 (5.0%) COVID-19 --- 1 (12.5%) --- --- 1 (12.5%) 2 (5.0%) Dizziness --- --- 1 (12.5%) 1 (12.5%) --- 2 (5.0%) Headache --- 1 (12.5%) --- --- 1 (12.5%) 2 (5.0%) Injection site bruising --- --- 1 (12.5%) 1 (12.5%) --- 2 (5.0%) Injection site pain --- 1 (12.5%) --- --- 1 (12.5%) 2 (5.0%)

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![Slide 13](mbx-ex99_1s13.jpg)

Canvuparatide (MBX 2109) Phase 1: Safety Results AE = adverse event; TEAE = treatment-emergent adverse event 1. Most common TEAEs defined in those occurring in ≥ 3 patients in any treatment group. Canvuparatide was generally well-tolerated No dose limiting toxicity or off-target AEs No related serious or severe TEAEs Most TEAE1 were injection site reactions (31%); generally mild, red, non-raised lesions less than 5 cm in diameter and resolved without intervention As expected in a study investigating the dose range for a PTH agonist, hypercalcemia occurred at the top doses; it was asymptomatic and resolved without intervention

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![Slide 14](mbx-ex99_1s14.jpg)

Plasma Concentration-time Profile for Active Drug Demonstrated Infusion-like Profile and Supported Once-weekly Dosing QW = once weekly; AUC0-τ = area under the concentration-time curve over a dosing interval; Cmax = maximal observed concentration; Tmax = time of the maximum observed concentration; T1/2 = terminal elimination half-life Active drug mean (SD) concentration, nmol/L 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 Day 1 48 96 144 96 0 48 96 144 0 48 96 144 0 48 336 144 504 840 Time post dose, hours Day 8 Day 15 Day 22 MBX 2109 active drug Lower limit of quantification (0.2 nmol/L) 200 μg MBX 2109 QW (n = 8) 400 μg MBX 2109 QW (n = 8) 600 μg MBX 2109 QW (n = 8) 900 μg MBX 2109 QW (n = 8) Active drug Cmax and AUC0-τ were dose proportional after 4th dose Active drug Tmax ~2.5 days Active drug T1/2 (half life) of ~8 (7.7-8.9) days supports once weekly dosing Accumulation decreased with each dose with Cmax generally similar after 3rd and 4th dose Active drug mean peak to trough ranged 1.47 to 1.79 over 1 week Active drug has low/moderate inter-subject variability in AUC0-τ and Cmax

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![Slide 15](mbx-ex99_1s15.jpg)

Maximal Increases in Serum Calcium Levels (Emax,adj) After Canvuparatide (MBX 2109) Weekly Injections Demonstrated Dose-and Time-dependent Effect Emax,adj were observed approximately 48 hours after injection Emax, adj (mg/dL) (mean (SD)) Placebo 200 μg MBX 2109 400 μg MBX 2109 600 μg MBX 2109 900 μg MBX 2109 1 8 15 22 1 8 15 22 Day: 1 8 15 22 1 8 15 22 1 8 15 22

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![Slide 16](mbx-ex99_1s16.jpg)

Endogenous PTH in Healthy Subjects Decreased After Canvuparatide (MBX 2109) Weekly Injections in a Dose- and Time-dependent Fashion Parathyroid Hormone, Intact (pg/mL) (mean (SD)) Placebo 200 μg MBX 2109 400 μg MBX 2109 600 μg MBX 2109 900 μg MBX 2109 Lower Limit of Normal 1 4 12 19 1 4 12 19 1 4 12 19 1 4 12 19 1 4 12 19 Day:

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![Slide 17](mbx-ex99_1s17.jpg)

Canvuparatide (MBX 2109) Phase 1: PK / PD results The half-life of the canvuparatide active drug across all doses was approximately 7.7 to 8.9 days, which we believe supports a once-weekly dosing regimen Mean peak-to-trough ratios of the active drug following the last dose ranged from 1.47 to 1.79, indicating a continuous, infusion-like profile over a seven-day period Demonstrated a dose and time-dependent effect in increasing serum calcium levels w/ an initial effect within days after the first dose and nearly maximal after the third dose Observed a dose dependent reduction in PTH to levels at or below the lower limit of normal for PTH with the maximal effect seen between one and four days after the initial injection Suppression of endogenous PTH secretion further substantiated the PTH agonist activity at the doses evaluated

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![Slide 18](mbx-ex99_1s18.jpg)

(Phase 2) Trial Overview: Canvuparatide (MBX 2109) ClinicalTrials.gov Identifier: NCT06465108 Enrollment complete; TLR anticipated in Q3 2025 Endpoints Primary: Normalization of albumin-adjusted serum calcium while independent from active vitamin D and calcium supplements (<600 mg/day) at Week 12 Secondary: Safety, PK, PD, PRO Safety and tolerability Urine calcium, serum phosphorus, 1,25 dihydroxyvitamin D, bone biomarkers PK profile Patient reported outcome (PRO) assessments Screening & ≤ 4-Week Optimization Period 12-Week Treatment Period 4-Week Follow-up Period 4- Week Fixed Dose Treatment Period 8-Week Dose Adjustment Period MBX 2109 800 μg weekly OR N=64 MBX 2109 600 μg weekly MBX 2109 400 μg weekly Placebo weekly Titrate MBX 2109 Titrate MBX 2109 Titrate MBX 2109 Titrate Placebo R Entry into Extension Study Trial Design

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![Slide 19](mbx-ex99_1s19.jpg)

MBX 1416: Long-Acting GLP-1 Receptor Antagonist for Post-bariatric Hypoglycemia

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![Slide 20](mbx-ex99_1s20.jpg)

Post-bariatric Hypoglycemia (PBH): a Rare, Serious and Chronic Complication of Bariatric Surgery 1. Fischer et al Surg Obes Relat Dis. 2021, 2. Michaels et al Obes Surg. 2017, 3. Lee et al Obesity 2015, 4. Internal Estimates Estimated >90,000 patients in U.S.1,2,3,4 Severe Hypoglycemia Neuroglycopenia symptoms including seizures, loss of consciousness, confusion, weakness, dizziness and blurred vision Rapid transit of nutrients into intestines stimulates excess GLP-1 and insulin secretion; occurs after a meal PBH presents six months to years after roux-en-Y gastric bypass and sleeve gastrectomy Unpredictable timing and frequency Social isolation Diminished quality of life, including disability Glucagon injection may be required CAUSE1,2 SYMPTOMS PATIENT IMPACT

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![Slide 21](mbx-ex99_1s21.jpg)

Managing PBH: No Currently Approved Pharmacotherapies 1. Suhl E et al Surg Obes Relat Dis 2017, 2. Salehi M et al JCEM 2018 Includes restricted diet, off-label medications and surgery Once-daily PBH investigational therapy Once-weekly PBH investigational therapy STANDARD OF CARE1,2 Frequent, small meals and avoid/limit high glycemic index foods Limited efficacy and long-term adherence challenges Off-label use of acarbose, diazoxide and octreotide Limited clinical data Side effect profiles and cost may limit patient adherence Avexitide GLP-1 receptor antagonist in Phase 3 development Designed to: Provide daily and nightly prevention of severe hypoglycemia and associated risks Offer convenient weekly dosing Improve QoL Eliminate need for rescue therapy (glucagon) and surgical intervention IN DEVELOPMENT MBX 1416

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![Slide 22](mbx-ex99_1s22.jpg)

MBX 1416 Phase 1 Trial Endpoints Primary: Secondary: To evaluate safety and tolerability Pharmacokinetic (PK) profile of MBX 1416 Pharmacodynamic (PD) – Response to Mixed Meal Tolerance Test (MAD) SAD (n=32) COMPLETE MAD (n=23) COMPLETE n=8 subjects/cohort (2 placebo: 6 active) Treatments: placebo or MBX 1416 dosed at 10, 30, 100 and 200 mg SC n=up to 8 subject/cohort (2 placebo: 6 active) Treatments: placebo or MBX 1416 dosed at 10 mg, 15 mg in 2 injections, or 30 mg SC QW x 4 Single and Multiple Ascending Doses of MBX 1416 in healthy adult subjects1 1. ClinicalTrials.gov Identifier: NCT06036784; A cohort (n=14) evaluated potential drug-drug interaction (DDI) of MBX 1416 on rosuvastatin exposure and on gastric emptying by using acetaminophen

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![Slide 23](mbx-ex99_1s23.jpg)

Overall Summary of Adverse Events Single dose cohorts (SAD and DDI): No Grade 3 or 4 AEs Multiple dose cohorts (MAD): No Grade 4 AEs; 5 subjects (4 subjects in the 30 mg and 1 subject in the 10 mg cohorts) experienced Grade 3 AEs (all ISRs) after the 3rd or 4th dose based only on erythema at the injection site >10 cm Except for AEs related to ISRs, no pattern or imbalance between MBX 1416 and placebo were observed for any AE No serious AEs and no Grade 4 AEs observed DDI = drug-drug interaction 1. Adverse events whose relationship to study drug was 'related', 'probably related', or 'possibly related' SAD MAD DDI MBX 1416(N=24) Placebo(N=8) MBX 1416(N=18) Placebo(N=5) Rosuvastatin + Acetaminophen (N=14) MBX 1416 45 mg + Rosuvastatin + Acetaminophen (N=14) Number of Subjects with any TEAEs 10 (41.7%) 4 (50.0%) 13 (72.2%) 3 (60.0%) 2 (14.3%) 2 (14.3%) Grade 3 --- --- 5 (27.8%) --- --- --- Grade 4 --- --- --- --- --- --- Treatment-related1 3 (12.5%) --- 13 (72.2%) 1 (20.0%) --- 1 (7.1%) With Any Serious TEAE --- --- --- --- --- --- Leading to Treatment Discontinuation --- --- 3 (16.7%) --- --- ---

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![Slide 24](mbx-ex99_1s24.jpg)

Injection Site Reactions (ISRs) Assessment Summary Given injectable peptides are known to cause ISRs, we proactively collected all ISRs, including mild reactions, using a dedicated form and the FDA Toxicity Grading Scale ISRs were observed in 73% of subjects who received MBX 1416 compared to 0% of subjects in the placebo group In 88% of subjects, ISRs were mild or moderate (Grade 1 or 2), predominantly characterized by: Erythema or redness (95% of subjects with an ISR) Minimal or no pain Resolution generally within ~7 days No systemic clinical manifestations were observed in association with ISRs Histological characterization of a Grade 3 ISR1 that developed in a subject from a MAD 30 mg cohort suggests a commonly observed reaction with peptide therapeutics, i.e., delayed-type hypersensitivity ISR ISRs were common and mostly mild/moderate 1. Grade 3 erythema defined based on size >10 cm

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![Slide 25](mbx-ex99_1s25.jpg)

Pharmacokinetics of Single and Multiple Doses of MBX 1416 MBX 1416 exposures were reproduceable and increased dose-proportionally Half-life of approximately 90 hours, supporting once-weekly dosing MBX 1416 concentrations increased dose-proportionally over the 10 to 200 mg dose range Steady-state achieved by the third dose Median tmax of 36-48 hours at steady state Some accumulation (≤1.31) observed for 10 mg and 30 mg dose levels Peak-to-trough ratio ~2.5 Low inter-subject variability 1 10 100 1000 10000 100000 0 168 336 504 672 840 1008 1176 1344 SAD 10 mg SAD 30 mg SAD 100 mg SAD 200 mg MAD 10 mg MAD 30 mg (2x15 mg and 1x30 mg) Nominal Time (h) Mean MBX 1416 Concentration (ng/mL)

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![Slide 26](mbx-ex99_1s26.jpg)

Pharmacodynamic Effect of MBX 1416 Observed During MMTT Increase in GLP-1 reaches statistical significance at early timepoints on Day 9 and Day 23 As expected in healthy subjects, no meaningful changes from baseline or between MBX 1416 and placebo were observed in the other parameters measured during the mixed meal tolerance test, for example glucose, insulin, or C-peptide Increase in placebo-adjusted GLP-1 peak from baseline during first 60 mins of MMTT conducted 1 day after 2nd and 4th doses MMTT = mixed meal tolerance test; CFB = change from baseline -20 -10 0 10 20 30 0 30 60 90 120 150 180 210 240 270 300 Day 9 Nominal Time (min) Mean (±SD) placebo-adjusted CFB Total GLP-1 Concentration (pmol/L) 0, -2.77 0, -2.404 -20 -10 0 10 20 30 0 30 60 90 120 150 180 210 240 270 300 Nominal Time (min) Mean (±SD) placebo-adjusted CFB Total GLP-1 Concentration (pmol/L) Day 23 MAD 10 mg MAD 30 mg (2x15 mg and 1x30 mg)

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![Slide 27](mbx-ex99_1s27.jpg)

Key Highlights from Phase 1 Study of MBX 1416 MBX 1416 was generally well tolerated with a favorable safety profile No MBX 1416 dose-related serious adverse events were observed, and the majority of TEAEs were mild or moderate injection site reactions MBX 1416 concentrations increased dose-proportionally in both the SAD and MAD cohorts PK profile supportive of weekly administration: In the MAD, MBX 1416 median half-life was approximately 90 hours Median Tmax of MBX 1416 at steady state was between 36 and 48 hours post-dose Consistent with known GLP-1 antagonism effect on gastric motility, a slight acceleration of gastric emptying was observed with MBX 1416 based on acetaminophen exposure MBX 1416 had no meaningful effect on rosuvastatin exposure, a commonly prescribed statin In mixed meal tolerance tests, MBX 1416 appeared to increase GLP-1 within 60 mins suggesting a PD effect in healthy volunteers that may translate into a therapeutic benefit in PBH patients; no meaningful changes observed in other parameters (glucose, insulin, c-peptide), as expected in healthy volunteers TEAE = treatment emergent adverse event; ISR = injection site reaction; SAD = single ascending dose; MAD = multiple ascending dose; DDI = drug-drug interaction Tmax = time to reach maximum concentration

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![Slide 28](mbx-ex99_1s28.jpg)

Obesity Portfolio

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Obesity: a Global Epidemic with Large Potential Commercial Opportunity Obese=(BMI>30 kg/m2); Overweight= (BMI 25.0-29.9 kg/m2) 1. 2020 U.S. adult population www.census.gov; 2. www.cdc.gov/nchs/data/hestat/obesity-adult-17-18/obesity-adult.htm MBX scientific founder, Richard DiMarchi, PhD Multiple candidates in discovery/pre-clinical development for obesity offer treatment flexibility Leveraging PEP™ platform technology for optimized PK and infrequent dosing Discovered by Dr. DiMarchi, inventor of first dual and triple incretin agonists U.S. Adult Population: 258.3 million1 ~42.5% obese2 ~31.1% overweight2 Potential addressable U.S. Patient Population: ~190.1 million

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MBX 4291: Long-acting GLP-1/GIP Receptor Co-agonist Prodrug in Development for Obesity Press Release: Dec. 4, 2024: Lilly's Zepbound® (tirzepatide) superior to Wegovy® (semaglutide) in head-to-head trial showing an average weight loss of 20.2% vs. 13.7% Designed as a high potency GLP-1/GIP receptor co-agonist utilizing PEP™ technology Dual-agonism results in statistically and clinically meaningful greater weight loss relative to mono-agonism IND-enabling studies complete; IND submission anticipated in Q2 2025 Potential for once-monthly administration, improved GI tolerability, and increased maximal weight loss

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In vitro Receptor Binding of MBX 4291 Active Drug has Similar Activity in Binding to the GLP-1 and GIP Receptors as Tirzepatide1 1. tirzepatide, a GLP-1/GIP co-agonist, is marketed as Zepbound® for the treatment of obesity hGLP-1R hGIPR tirzepatide MBX 4291 (active drug) CPS (mean) Concentration, nM Concentration, nM CPS (mean) hGLP-1R hGIPR tirzepatide 0.67 ± 0.39 0.094 ± 0.059 MBX 4291 (active drug) 0.56 ± 0.19 0.077 ± 0.055 Counts Per Second (mean) Counts Per Second (mean)

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MBX 4291 Active Drug Demonstrated Extended Time-action Profile in NHPs Compared to Tirzepatide that may Support Once-monthly Dosing NHP = non-human primates TZP = tirzepatide

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MBX 4291 Infusion-like Profile Demonstrated in Once-weekly Repeat Administration in NHPs NHP = non-human primates

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Bodyweight (g) (mean) Time (Days) Time (Days) MBX 4291 Active Drug Produced Similar Reductions in Body Weight and Food Intake as Tirzepatide in DIO Mouse Model DIO = diet-induced obesity Dosing = 3 nmol/kg daily Days 0-4, 1.5 nmol/kg daily Days 5-10 Vehicle tirzepatide MBX 4291 (active drug) Bodyweight Food Intake Food Intake (g) (mean)

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MBX 4291 Demonstrated Significant Weight Loss vs. Baseline in NHPs NHP = non-human primates 1

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PROGRAM MILESTONE ANTICIPATED TIMING Canvuparatide (MBX 2109) Avail™ (Phase 2) Enrollment Completion Complete Avail™ (Phase 2) Topline Results Q3 2025 MBX 1416 Phase 1 Topline Results Complete End of Phase 1 Meeting Mid-2025 Phase 2 Initiation 2H 2025 MBX 4291 IND Submission Q2 2025 Phase 1 Initiation 2H 2025 Substantial Value Inflection Opportunities in 2025

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Thank You www.mbxbio.com investors@mbxbio.com