Monte Rosa Therapeutics, Inc. 8-K Filing

Ticker: GLUE · Form: 8-K · Filed: Dec 16, 2025 · CIK: 1826457

Monte Rosa Therapeutics, Inc. 8-K Filing Summary
FieldDetail
CompanyMonte Rosa Therapeutics, Inc. (GLUE)
Form Type8-K
Filed DateDec 16, 2025
Pages6
Reading Time7 min
Key Dollar Amounts$0.0001
Sentimentneutral

Sentiment: neutral

FAQ

What type of filing is this?

This is a 8-K filing submitted by Monte Rosa Therapeutics, Inc. (ticker: GLUE) to the SEC on Dec 16, 2025.

What are the key financial figures in this filing?

Key dollar amounts include: $0.0001 (nge on which registered Common Stock, $0.0001 par value per share GLUE The Nasdaq).

How long is this filing?

Monte Rosa Therapeutics, Inc.'s 8-K filing is 6 pages with approximately 1,858 words. Estimated reading time is 7 minutes.

Where can I view the full 8-K filing?

The complete filing is available on SEC EDGAR. You can also read the AI-decoded analysis with risk assessment and key highlights on ReadTheFiling.

Filing Stats: 1,858 words · 7 min read · ~6 pages · Grade level 14.5 · Accepted 2025-12-16 07:30:38

Key Financial Figures

  • $0.0001 — nge on which registered Common Stock, $0.0001 par value per share GLUE The Nasdaq

Filing Documents

01. Regulation FD Disclosure

Item 7.01. Regulation FD Disclosure On December 16, 2025, Monte Rosa Therapeutics, Inc. (the "Company" or "Monte Rosa") issued a press release titled "Monte Rosa Therapeutics Announces Compelling Clinical Activity of MRT-2359 in Combination with Enzalutamide in Heavily Pretreated Metastatic Castration Resistant Prostate Cancer Patients with Androgen Receptor Mutations". The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. Also, on December 16, 2025, the Company will host a webcast to discuss interim results from its ongoing Phase 1/2 clinical study evaluating MRT-2359 in combination with enzalutamide in heavily pretreated patients with metastatic castration resistant prostate cancer ("CRPC"). A copy of the presentation from the webcast will be available on the "Presentations" page of the Company's website at www.monterosatx.com and is furnished as Exhibit 99.2 to this Current Report on Form 8-K. The information in Item 7.01 of this Form 8-K (including Exhibits 99.1 and 99.2) shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

01. Other Events

Item 8.01. Other Events On December 16, 2025, the Company announced positive interim data from its ongoing Phase 1/2 clinical study evaluating MRT-2359 in combination with enzalutamide in heavily pretreated patients with metastatic CRPC. The Phase 1/2 study evaluated 0.5 mg and 0.75 mg of MRT-2359 administered orally on a 21-days-on, 7-days-off drug schedule in combination with enzalutamide, an AR inhibitor. The study population as of the data cutoff date of December 3, 2025, included 20 individuals with advanced CRPC who were heavily pretreated, including 15 (75%) previously treated with a second-generation AR inhibitor, 16 (80%) previously treated with taxane chemotherapy, and 11 (55%) previously treated with Pluvicto. For analysis of efficacy, all patients were required to be evaluable for measurable disease and not have acquired neuroendocrine differentiation, as determined by RNAseq from screening biopsies. Summary of Phase 1/2 Study Results in Metastatic CRPC Patients All 20 patients enrolled were evaluable for safety. The combination of MRT-2359 and enzalutamide maintained a favorable safety profile, with manageable, primarily gastrointestinal adverse events that were classified as mild or moderate (Grade 1 or Grade 2). Of the 20 patients enrolled, 14 patients were evaluable for RECIST (Response Evaluation Criteria in Solid Tumors) and were confirmed to have non-neuroendocrine mCRPC. Of the 14 evaluable patients, all of whom were assessed for AR alteration status using post hoc ctDNA analysis, 4 were confirmed to have AR mutations, and all 4 of those had PSA responses, including 2 patients with PSA90 responses. 2 RECIST partial responses (1 confirmed partial response and 1 unconfirmed partial response) were seen in the AR mutant subset and the DCR in the AR-mutant setting was 100%. In addition, 5 patients with wild-type AR or positive for ARV7 transcripts had stable disease per RECIST, several of which were associated with tumor size reducti

Forward-Looking Statements

Forward-Looking Statements This communication includes express and implied "forward-looking statements," including forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements that are not historical facts and in some cases, can be identified by terms such as "may," "might," "will," "could," "would," "should," "expect," "intend," "plan," "objective," "anticipate," "believe," "estimate," "predict," "potential," "continue," "ongoing," or the negative of these terms, or other comparable terminology intended to identify statements about the future. Forward-looking statements contained herein include, but are not limited to, statements about our ability to grow our product pipeline, our ability to successfully complete research and further development and commercialization of our drug candidates in current or future indications, including the timing and results of our clinical trials and our ability to conduct and complete clinical trials, statements regarding the promising interim results from our ongoing Phase 1/2 clinical study evaluating MRT-2359 in combination with enzalutamide in heavily pretreated patients with metastatic CRPC, our expectations regarding the clinical activity observed with MRT-2359 in combination with enzalutamide in heavily pretreated mCRPC patients and the significant opportunity for MRT-2359 in the rapidly evolving treatment landscape of prostate cancer, our plans to initiate a signal-confirming Phase 2 study evaluating MRT-2359 in combination with a second generation AR inhibitor in mCRPC patients with AR mutations and timing thereof, with potential to expand into additional patient subsets, the potential for the data from this study to confirm MRT-2359's clinical activity and position the program for advancement into registrational studies, the clinical significance of the clinical data read-out at upcoming scientific meetings and timing thereof, our

01. Financial Statements and Exhibits

Item 9.01. Financial Statements and Exhibits (d) Exhibits 99.1 Press Release issued by Monte Rosa Therapeutics, Inc. dated December 16, 2025. 99.2 MRT-2359 Phase 1/2 Clinical Data Update Presentation furnished by Monte Rosa Therapeutics, Inc. on December 16, 2025. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). SIGNATURE 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. Monte Rosa Therapeutics, Inc. Date: December 16, 2025 By: /s/ Markus Warmuth Markus Warmuth President and Chief Executive Officer

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