Every 8-K that MBX Biosciences, Inc. (MBX) has filed with the SEC in the last 24 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A 8-K covers material events a company has to report between its quarterly reports, so if you follow MBX and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full MBX filings page.
MBX Biosciences, Inc. (MBX) reported that the first patient has been dosed in its pivotal Phase 3 oPTimize trial of once-weekly canvuparatide for adults with chronic hypoparathyroidism. This global, randomized, double-blind, placebo-controlled study is intended as a registrational trial and uses the same device planned for potential commercial use.
The trial will enroll approximately 160 adults with chronic hypoparathyroidism, randomized 3:1 to canvuparatide or placebo over a 26‑week double-blind period, followed by a 78‑week open-label extension. Dosing includes a fixed 600 microgram period, titration up to 1,600 micrograms weekly, and a maintenance phase. The primary endpoint is a composite responder rate at Week 26 based on serum calcium control, reduced reliance on active vitamin D and calcium supplements, and dose stability. MBX highlights prior positive Phase 2 Avail data and notes that canvuparatide has Orphan Drug/Orphan Designation in the U.S. and EU.
MBX Biosciences, Inc. reported second-quarter 2026 results and extensive pipeline progress in endocrine and metabolic disorders. As of June 30, 2026, it held $418.6 million in cash, cash equivalents and marketable securities, which management expects will fund operations into 2029. For the quarter, research and development expenses were $31.0 million and general and administrative expenses were $9.9 million, leading to a net loss of $37.1 million, or $0.78 per share.
The company highlighted once-weekly canvuparatide for chronic hypoparathyroidism, with the pivotal Phase 3 oPTimize trial expected to initiate in the third quarter of 2026 following Phase 2 and one-year open-label extension data showing sustained benefit. In obesity, preliminary Phase 1 data for MBX 4291 showed a mean weight loss of 7% at eight weeks in the first multiple ascending dose cohort and pharmacokinetics that support once-monthly dosing, with 12-week MAD results planned for the fourth quarter of 2026. MBX also nominated two additional once-monthly obesity candidates, MBX 5765 (amycretin) and MBX 6180 (GLP-1/GIP/GCG triple agonist), and appointed Steve Hoerter as Chairman and Chief Executive Officer and John Smither as Chief Financial Officer.
MBX Biosciences, Inc. reports that Chief Executive Officer and director Kent P. Hawryluk will leave both roles effective July 13, 2026. He will provide transition and strategic advisory services as a consultant through August 16, 2026. His separation terms include 12 months of base-salary severance, up to 12 months of Company-paid COBRA continuation coverage, a cash bonus equal to his target annual bonus, accelerated vesting of time-based equity that would have vested through August 16, 2027, and an extension of the post-termination stock option exercise period to July 13, 2027. The company states his departure is not due to a dispute or disagreement.
The Board appointed executive chairman Steven Hoerter as President, Chief Executive Officer and principal executive officer effective July 13, 2026, with a base salary of $665,000, a target annual bonus equal to 60% of base salary, options to purchase 331,000 shares and 71,000 RSUs, subject to multi‑year vesting. Interim Chief Financial Officer John Smither was named Chief Financial Officer and principal financial officer, effective the same date, with a $530,000 base salary, 40% target bonus, a $150,000 relocation bonus, options on 130,000 shares and 28,000 RSUs, also subject to multi‑year vesting.
MBX Biosciences reported one-year Phase 2 and open-label extension data for once-weekly canvuparatide in adults with chronic hypoparathyroidism. In the 12-week Avail trial, 63% of canvuparatide-treated patients (30/48) met the primary composite endpoint versus 31% on placebo (5/16), showing better control of calcium with reduced dependence on supplements. At one year, 57% of evaluable patients (31/54) were responders with no rescue therapy used in the final week, and 90% of patients entering the extension remained on treatment, indicating strong durability and retention.
Pharmacokinetic data showed a Tmax of 2–3 days and a peak‑to‑trough ratio around 1.3, supporting stable once-weekly dosing. Mean serum calcium stayed in the normal range while 24‑hour urine calcium fell and remained normal, kidney function (eGFR) improved, and bone turnover markers and bone mineral density shifted in patterns consistent with physiologic PTH replacement. Canvuparatide was generally well tolerated through one year, with most adverse events mild or moderate, no treatment-related serious events, and injection site reactions in 10% of patients. MBX plans to start a Phase 3 pivotal trial in Q3 2026 and reports about $440 million in cash, cash equivalents and marketable securities as of March 31, 2026, which it estimates will fund operations into 2029.
MBX Biosciences, Inc. reported the results of its 2026 annual meeting of stockholders held on June 4, 2026. Stockholders elected two Class II directors, Patrick J. Heron and Edward T. Mathers, to serve terms ending at the 2029 annual meeting.
As of the April 10, 2026 record date, there were 47,570,485 outstanding shares of common stock. Heron received 35,007,623 votes for and 4,579,129 withheld, while Mathers received 31,983,223 votes for and 7,603,529 withheld, with 4,130,833 broker non-votes for each. Stockholders also ratified Ernst & Young LLP as independent registered public accounting firm for the year ending December 31, 2026, with 43,713,693 votes for, 1,946 against and 1,946 abstentions.
MBX Biosciences provided a comprehensive update on its obesity and peptide-therapy pipeline, highlighted by initial Phase 1 data for MBX 4291, a GLP-1/GIP co-agonist prodrug for obesity. In the first multiple ascending dose cohort, preliminary blinded data showed mean weight loss of 7% at eight weeks in eight participants (including two on placebo), with only one mild gastrointestinal event and no serious adverse events. Pharmacokinetic data from single- and multiple-dose cohorts demonstrated gradual accumulation, a delayed time to peak concentration around 13–14 days, and a T1/2Cmax of about 26 days, all supporting the potential for true once-monthly dosing.
The company also nominated MBX 5765, an amycretin prodrug combining GLP-1, GIP, glucagon and DACRA activity, as a once-monthly obesity candidate slated for IND-enabling studies in Q2 2026, and plans to nominate a triple agonist in Q3 2026. Once-weekly imapextide achieved proof of concept in post-bariatric hypoglycemia with dose-dependent improvements in glucose nadir and insulin peak, though MBX will not pursue a Phase 2b trial as it reallocates resources toward canvuparatide and its obesity portfolio. Management reiterated multiple 2026 catalysts and noted unaudited cash, cash equivalents and marketable securities of $440 million as of March 31, 2026, expected to fund operations into 2029.
MBX Biosciences reported a first quarter 2026 net loss of $23.5M, similar to a $23.9M loss a year earlier, as it continues investing in its endocrine and metabolic pipeline. Cash, cash equivalents and marketable securities were $440.0M as of March 31, 2026, which the company expects will fund operations into 2029.
R&D expenses fell to $18.5M while G&A expenses rose to $8.8M, reflecting both lower trial costs and ongoing infrastructure build-out. MBX highlighted progress for once-weekly canvuparatide in hypoparathyroidism, including planned Phase 3 initiation in Q3 2026, expansion of its obesity portfolio around MBX 4291 and new candidates, and Phase 2 advancement of imapextide for post-bariatric hypoglycemia.
MBX Biosciences reported a larger full-year 2025 net loss of $86.97M, up from $61.92M in 2024, as it increased investment in its pipeline. Research and development spending rose to $79.16M, while general and administrative expenses grew to $18.90M as the company expanded its operations.
As of December 31, 2025, MBX held $373.71M in cash, cash equivalents and marketable securities, and subsequently raised an additional $85.4M through its ATM program, for pro forma cash and investments of $459.1M, which it expects will fund operations into 2029. The company is preparing a Phase 3 trial of once-weekly canvuparatide for hypoparathyroidism targeted to start in Q3 2026, advancing MBX 4291 in Phase 1 for obesity with 12-week data anticipated in Q4 2026, and running a Phase 2a trial of imapextide for post-bariatric hypoglycemia with results expected in Q2 2026.
MBX Biosciences reported a successful End-of-Phase 2 meeting with the FDA for once-weekly canvuparatide, clearing the way to start a Phase 3 trial in chronic hypoparathyroidism in Q3 2026. The double-blind, placebo-controlled study will enroll about 160 patients, randomizing them 3:1 to canvuparatide or placebo, with fixed-dose, titration and maintenance periods and a primary efficacy assessment at week 26.
The trial will track how many patients reach normal blood calcium while no longer needing conventional therapy, along with urinary calcium and other secondary measures, followed by an open-label extension. MBX also highlighted that canvuparatide has orphan drug designation from both the FDA and the European Medicines Agency for chronic hypoparathyroidism, supporting its continued development in the U.S. and Europe.
MBX Biosciences signed a lease for about 13,642 square feet of new office and lab space in Burlington, Massachusetts. The four-year lease is expected to start around May 1, 2026, with base rent of roughly $68,200 for the first twelve months and aggregate base rent of about $3.4 million, plus operating costs, taxes and utilities.
The company’s Chief Financial Officer, Richard Bartram, will resign effective March 15, 2026, then serve as a consultant to support the transition. He will receive severance under his employment agreement, extended option exercise rights, and a $13,400 lump sum related to COBRA premiums. John Smither, an experienced biotechnology finance executive, has been appointed Interim CFO with a part-time employment agreement that includes a $325,000 base salary, a target bonus equal to 40% of earned income, and a $25,000 sign-on bonus.
MBX Biosciences, Inc. closed an at-the-market stock sale, issuing 2,250,986 shares of common stock at a volume weighted average price of $38.76 per share for gross proceeds of approximately $87.1 million. The shares were sold through Jefferies under an existing Open Market Sale Agreement and shelf registration on Form S-3.
The company currently plans to use the net proceeds to fund clinical-stage programs, discovery research and development, additional clinical development, and general corporate purposes including working capital and capital expenditures. MBX Biosciences may also use some proceeds and existing cash to in-license, acquire, or invest in complementary businesses or technologies, and still has capacity to sell up to an additional $62.9 million of common stock under the same program.
MBX Biosciences, Inc. announced that its board of directors has appointed Laurie Stelzer as a new independent director, effective January 20, 2026. She was designated as a Class I director and will serve until the company’s 2028 annual meeting of stockholders, then continue until a successor is elected and qualified or until an earlier departure.
With her addition, the board size is set at eight directors, and she fills an existing vacancy. As a non-employee director, she will receive the same compensation as other non-employee directors under the company’s disclosed director compensation policy, and she will enter into the standard indemnification agreement used for other directors.
Ms. Stelzer has also been appointed to serve as a member and chairperson of the Audit Committee, replacing Ed Mathers on that committee, and will serve on the Compensation Committee. The compositions of the Nominating and Corporate Governance Committee and the Science and Medicine Committee remain unchanged.
MBX Biosciences reported preliminary unaudited cash, cash equivalents and marketable securities of $373.7 million as of December 31, 2025, which it currently expects will fund operations into 2029. This estimate is based on assumptions and may change once the ongoing audit of its 2025 financial statements is completed. The company also plans to expand its obesity portfolio in 2026 with two additional obesity drug candidates, with nominations anticipated in the second and third quarters of 2026. Related outlook and business updates were also discussed in a press release furnished as an exhibit.
MBX Biosciences filed an 8-K noting it furnished a press release announcing financial results for the quarter ended September 30, 2025. The release is provided as Exhibit 99.1 and is furnished, not filed, under Item 2.02.
Under Item 5.02, the company reported governance updates. On October 31, 2025, James M. Cornelius resigned from the Board and as Audit Committee chair; the company stated there was no disagreement with MBX regarding operations, policies or practices. Effective November 6, 2025, director Steven Hoerter was appointed executive chairperson. He will receive chair compensation and an option to purchase 100,000 shares vesting monthly over one year. The Audit Committee now comprises Tiba Aynechi (chair), Steven Hoerter, and Ed Mathers.
MBX Biosciences entered into an underwriting agreement for an underwritten public stock offering. The company sold 11,108,055 shares of common stock at an offering price of $18.00 per share and granted underwriters a 30-day option to purchase up to an additional 1,666,208 shares at the same price, less discounts and commissions. The offering closed on September 26, 2025.
The transaction generated approximately $187.5 million in net proceeds. MBX plans to use this cash, together with its existing cash, cash equivalents and short-term investments, primarily to advance development of its three clinical-stage programs. Remaining funds are earmarked for discovery research and development, additional clinical development, and general corporate purposes including working capital and capital expenditures.
MBX Biosciences reported positive topline results from its Phase 2 Avail™ trial of once-weekly canvuparatide in adults with chronic hypoparathyroidism. At 12 weeks, 63% of canvuparatide-treated patients (30/48) met the primary composite endpoint, compared with 31% on placebo (5/16) with a p-value of 0.042. In the six‑month open-label extension, 79% of treated patients (44/56 evaluable) were responders, and 94% of the original 64 patients chose to enter this extension.
Treatment was generally well tolerated, with no serious adverse events or deaths related to canvuparatide and no discontinuations attributed to the drug. Bone turnover markers increased versus placebo, and in patients whose elevated urine calcium normalized by Week 12, mean urine calcium fell 48% on canvuparatide versus 33% on placebo. The company plans to start a Phase 3 study of once-weekly canvuparatide in 2026.
MBX Biosciences, Inc. filed a current report describing progress in its obesity program. On September 4, 2025, the company dosed the first participant in a Phase 1 clinical trial of MBX 4291, a long-acting GLP-1/GIP receptor co-agonist prodrug being developed for the treatment of obesity.
The Phase 1 study is a randomized, double-blind, placebo-controlled, first-in-human trial in adults with obesity. It includes a single ascending dose part with five cohorts of eight participants and a four-week multiple ascending dose part with three cohorts of eight participants, all using a 3:1 randomization of MBX 4291 to placebo. After these parts, the company plans additional multiple-dose cohorts over 12 weeks in up to two groups of 30 participants each, using a 2:1 randomization.
Participants are followed for several weeks after dosing to evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics. MBX Biosciences anticipates topline Phase 1 results in 2027 and highlights that these plans and timelines are forward-looking and subject to clinical, regulatory, and funding risks.