Del-zota DMD data lift Avidity Biosciences (NASDAQ: RNA) toward 2025 BLA

Rhea-AI Filing Summary

Avidity Biosciences reported strongly positive one‑year data for its Duchenne muscular dystrophy therapy candidate delpacibart zotadirsen (“del-zota”) from the EXPLORE44 and EXPLORE44-OLE trials. Participants showed approximately 25 percent of normal dystrophin production, with total dystrophin restored up to 58 percent of normal, and creatine kinase levels reduced by greater than 80 percent and maintained near normal for up to 16 months.

Across multiple functional tests, del-zota patients improved or remained stable while matched natural history groups worsened, including better performance in stair climbing, walking/running, time to rise, and upper limb function. Del-zota demonstrated favorable long-term safety, with mostly mild or moderate adverse events and one discontinuation for hypersensitivity. Avidity plans to submit a Biologics License Application to the FDA at year end 2025, the first of three planned BLA submissions over a 12‑month period. The board also increased shares reserved under the 2022 Employment Inducement Incentive Award Plan from 4,500,000 to 8,000,000.

Positive

• Compelling one-year del-zota efficacy data in DMD: Approximately 25 percent of normal dystrophin production, total dystrophin up to 58 percent of normal, and greater than 80 percent creatine kinase reduction sustained up to 16 months, alongside functional improvements versus natural history comparators.
• Clear near-term regulatory path: Avidity states it remains on track to submit a Biologics License Application for del-zota to the FDA at year end 2025, the first of three planned BLA submissions over a 12‑month period.

Negative

• None.

Insights

Biotech clinical and regulatory analyst

Del-zota shows strong one-year DMD data and BLA timing.

The new EXPLORE44 and EXPLORE44-OLE results for del-zota in Duchenne muscular dystrophy are notable because they show biological and functional effects aligned with the disease mechanism. Participants achieved approximately 25 percent of normal dystrophin production and restored total dystrophin up to 58 percent of normal, while creatine kinase dropped by greater than 80 percent and stayed near normal for up to 16 months.

Functionally, treated patients improved or remained stable on key measures, whereas matched natural history groups declined. Examples include better 4-stair climb, 10-meter walk/run, time to rise from floor, and Performance of Upper Limb scores, with North Star Ambulatory Assessment remaining stable while the comparator declined. These differences, although based on relatively small del-zota cohorts, support the company’s description of reversal of disease progression compared to baseline and natural history.

Safety in EXPLORE44-OLE was described as favorable, with most treatment-emergent adverse events mild or moderate and one discontinuation due to hypersensitivity. Avidity “remains on track” to submit a Biologics License Application to the FDA at year end 2025, and identifies this as the first of three planned BLA submissions over a 12‑month period, highlighting a clear regulatory path anchored on these data.

Equity compensation and capital structure analyst

Avidity expands inducement equity pool, increasing share reserve.

The board approved an amendment to the 2022 Employment Inducement Incentive Award Plan, increasing common stock reserved for issuance from an aggregate of 4,500,000 shares to 8,000,000 shares. This expands the pool available for future inducement grants to new hires, which are typically used for recruiting and retaining talent, especially in growth or late-stage development phases.

While this change does not itself issue shares, it raises the maximum number that can be granted under this plan over time. The impact on existing holders will depend on how quickly and to what extent the company ultimately grants awards from this expanded reserve, information that would be detailed in future grant disclosures.

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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): September 9, 2025

  _________________________________________

AVIDITY BIOSCIENCES, INC. 

(Exact name of registrant as specified in its charter)

 _________________________________________

Delaware

001-39321

46-1336960

(State or other jurisdiction of incorporation or organization)

(Commission File Number)

(I.R.S. Employer Identification No.)

3020 Callan Road

San Diego, California 92121 92121

(Address of principal executive offices) (Zip Code)

(858) 401-7900

(Registrant’s telephone number, include area code)

10578 Science Center Drive, Suite 125

San Diego, California 92121 92121

(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:

☐ 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:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, par value $0.0001 per share

RNA

The Nasdaq Global Market

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.  ☐ 

 

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On September 9, 2025, the board of directors of Avidity Biosciences, Inc. ("Avidity" or the "Company") approved an amendment to the Avidity Biosciences, Inc. 2022 Employment Inducement Incentive Award Plan to increase the authorized number of shares of the Company's common stock reserved for issuance thereunder from an aggregate of 4,500,000 shares to an aggregate of 8,000,000 shares. A copy of the full text of this amendment is attached as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 7.01. Regulation FD Disclosure.

On September 10, 2025, the Company will host an investor and analyst event (the "Event") to discuss new data from participants treated continuously with delpacibart zotadirsen ("del-zota") for one year in the EXPLORE44® and EXPLORE44-OLE™ trials. The Event will begin at 8:00 a.m. Eastern Time and will be available via a live video webcast accessible under the "Events and Presentations" page in the "Investors" section of Avidity's corporate website, at https://www.aviditybiosciences.com. During the Event, the Company will present the corporate slide presentation attached as Exhibit 99.1 to this Current Report on Form 8-K, which is incorporated herein by reference.

The information contained in this Item 7.01, including in Exhibit 99.1 hereto and on Avidity’s corporate website, is being “furnished” and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), is not subject to the liabilities of that section and is not deemed 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.

Item 8.01. Other Events.

On September 10, 2025, the Company announced positive new data from participants treated continuously with del-zota for one year in the EXPLORE44 and EXPLORE44-OLE trials. These data demonstrated reversal of disease progression and unprecedented improvement compared to baseline and natural history across multiple functional measures. Additional data from the EXPLORE44 program will be presented at upcoming scientific congresses.

Trial participants treated with del-zota demonstrated statistically significant increases of approximately 25 percent of normal in dystrophin production and restored total dystrophin up to 58 percent of normal. Creatine kinase (“CK”) levels reduced by greater than 80 percent compared to baseline and were sustained at near normal levels throughout the duration of evaluation with participants followed for up to 16 months. Additionally, 50 percent of participants had CK levels within the normal range at one year of treatment.

A total of 17 participants (12 ambulatory and 5 non-ambulatory) who began on the del-zota treated arm of EXPLORE44 and continued into the EXPLORE44-OLE have been followed for approximately one year. Given the study design, some participants received 5 mg/kg once every six weeks (“Q6W”) and some received 10 mg/kg once every eight weeks during EXPLORE44. All participants were transitioned to the 5 mg/kg (Q6W) dosing schedule during EXPLORE44-OLE. Not all participants could complete all assessments. Functional data from these pooled dosing cohorts for del-zota treated participants, compared to DMD44 natural history (PRO-DMD-01), demonstrated improvement:

•4-Stair Climb (“4SC”): Improved from baseline by 2.1 seconds. In contrast, the natural history group declined from baseline by 2.7 seconds (DMD44 Nat Hx N=22; del-zota N=10).

•10-Meter Walk/Run Test (“10mWRT”): Improved from baseline by 0.7 seconds. In contrast, the natural history group declined from baseline by 1.5 seconds (DMD44 Nat Hx N=22; del-zota N=10).

•Time to Rise from Floor (“TTR”): Improved from baseline by 3.2 seconds. In contrast, the natural history group declined from baseline by 1.6 seconds (DMD Nat Hx N=19; del-zota N=6).

•North Star Ambulatory Assessment (“NSAA”): Remained stable. In contrast, the natural history group declined from baseline by 2.4 points (DMD44 Nat Hx N=20; del-zota N=10).

•Performance of Upper Limb (“PUL2”): Improved from baseline by 1.5 points. In contrast, the natural history group declined from baseline by 0.7 points. Similar PUL improvements were seen in both ambulatory and non-ambulatory participants (DMD44 Nat Hx N=27; del-zota N=17).

Safety was assessed in all participants in the EXPLORE44-OLE trial, and del-zota continued to demonstrate favorable long-term safety and tolerability as of the June 2025 data cutoff. Most treatment

emergent adverse events (“TEAEs”) were mild or moderate with the most common TEAEs (occurring in greater than 3 participants) being upper respiratory tract symptoms, diarrhea, fall, backpain and headache. One participant discontinued from EXPLORE44-OLE following an event of hypersensitivity.

Avidity remains on track to submit a Biologics License Application (“BLA”) to the U.S. Food and Drug Administration (“FDA”) at year end 2025. This will be Avidity’s first of three planned BLA submissions over a 12-month period. Avidity continues to prepare for a confirmatory study to support full global approval.

In the above studies, 4SC, 10mWRT, TTR and NSAA were only performed in ambulatory participants, and PUL was performed in ambulatory and non-ambulatory participants. PRO-DMD-01 was an observational, prospective natural history study (n=269) intended to study the progression of subjects with DMD. In collaboration with a third-party marketing research group engaged in the analysis of DMD progression based on natural history, a matched subset of DMD44 participants (n=22) was utilized to analyze progression on key ambulatory functional endpoints at 12 months. A different natural history comparator was used for the PUL 2.0 assessment based on a separate published natural history study (n=27). Natural history data may not be precisely matched to del-zota patient data or representative of the DMD44 patient population in other ways.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number						Description
10.1						Amendment to the Avidity Biosciences, Inc. 2022 Employment Inducement Incentive Award Plan.
99.1						Slide Presentation
104						Cover Page Interactive Data File (embedded within the Inline XBRL document)

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.

									AVIDITY BIOSCIENCES, INC.
Date: September 10, 2025						By:			/s/ Michael F. MacLean
									Michael F. MacLean
									Chief Financial Officer

FAQ

What did Avidity Biosciences (RNA) report about del-zota in Duchenne muscular dystrophy?

Avidity reported positive one-year data for delpacibart zotadirsen (“del-zota”) from the EXPLORE44 and EXPLORE44-OLE trials. The company stated that these data showed reversal of disease progression and unprecedented improvement compared to baseline and natural history across multiple functional measures in participants with Duchenne muscular dystrophy amenable to exon 44 skipping.

What biomarker changes were seen with del-zota in Avidity Biosciences (RNA) trials?

Trial participants treated with del-zota showed statistically significant increases of approximately 25 percent of normal in dystrophin production and restoration of total dystrophin up to 58 percent of normal. Creatine kinase levels were reduced by greater than 80 percent versus baseline and maintained near normal for up to 16 months, with 50 percent of participants having creatine kinase within the normal range at one year.

How did del-zota affect functional outcomes compared to natural history in the EXPLORE44 program?

Across multiple endpoints, del-zota participants improved or remained stable, while matched natural history groups declined. Examples include a 2.1-second improvement from baseline in the 4-stair climb versus a 2.7-second decline in natural history, a 0.7-second improvement in the 10-meter walk/run versus a 1.5-second decline, a 3.2-second improvement in time to rise versus a 1.6-second decline, stable North Star Ambulatory Assessment versus a 2.4-point decline, and a 1.5-point improvement in Performance of Upper Limb versus a 0.7-point decline.

What safety profile did Avidity Biosciences (RNA) report for del-zota?

Safety in EXPLORE44-OLE was described as favorable as of the June 2025 data cutoff. Most treatment-emergent adverse events were mild or moderate. The most common events, each occurring in more than three participants, included upper respiratory tract symptoms, diarrhea, fall, back pain and headache. One participant discontinued from EXPLORE44-OLE following a hypersensitivity event.

What are Avidity Biosciences’ (RNA) regulatory plans for del-zota?

Avidity stated that it remains on track to submit a Biologics License Application for del-zota to the U.S. Food and Drug Administration at year end 2025. The company indicated this will be its first of three planned Biologics License Application submissions over a 12‑month period and that it continues to prepare for a confirmatory study to support full global approval.

How did Avidity Biosciences (RNA) change its equity incentive plan in this 8-K?

The board approved an amendment to the Avidity Biosciences, Inc. 2022 Employment Inducement Incentive Award Plan to increase the authorized number of common shares reserved for issuance from an aggregate of 4,500,000 shares to an aggregate of 8,000,000 shares. The full text of the amendment is attached as Exhibit 10.1.

What upcoming investor event did Avidity Biosciences (RNA) describe?

Avidity will host an investor and analyst event on September 10, 2025, beginning at 8:00 a.m. Eastern Time, to discuss new one-year del-zota data from the EXPLORE44 and EXPLORE44-OLE trials. The event will be available via live video webcast through the Investors section of the company’s website, and the associated slide presentation is furnished as Exhibit 99.1.