Welcome to our dedicated page for Atrium Therapeutics SEC filings (Ticker: RNA), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Atrium Therapeutics filings document the corporate transition that created the current RNA issuer and the related Avidity Biosciences merger, separation and listing records. The filing set includes 8-K material-event reports, shareholder voting disclosures, separation and merger agreement records, capital-structure information and a Form 25 covering removal of Avidity common stock from Nasdaq listing and registration.
Regulatory disclosures tied to the symbol also cover governance matters, operating and financial results, clinical or regulatory updates and security-structure information. As an independent biopharmaceutical company, Atrium's filings center on its RNA therapeutics platform, precision cardiology pipeline, collaboration economics, equity compensation and public-company reporting obligations.
Avidity Biosciences, Inc. reported an insider transaction by President, CEO, and director Sarah Boyce. On January 7, 2026, she sold 8,576 shares of common stock at $72.23 per share. After this transaction, she beneficially owned 283,394 shares directly.
According to the disclosure, the sale was made solely to cover tax withholding obligations arising from the vesting of restricted stock units (RSUs) on January 6, 2026. The issuer’s equity incentive plans require these taxes to be funded through a mandatory “sell-to-cover” transaction, so this did not represent a discretionary trade. The filing notes that Boyce executed an instruction letter for the automatic sale of these shares, intended to satisfy the affirmative defense conditions of Rule 10b5-1.
Avidity Biosciences, Inc. Chief Technical Officer Charles Calderaro III reported an automatic sale of common stock to cover taxes from restricted stock unit (RSU) vesting. On January 7, 2026, he sold 3,727 shares of common stock at $72.23 per share in a mandated “sell-to-cover” transaction tied to RSUs that vested on January 6, 2026. This sale was required under the company’s equity incentive plan to satisfy tax withholding obligations and was executed under an instruction letter intended to meet Rule 10b5-1(c) affirmative defense conditions. Following the sale, he beneficially owned 49,797 shares of Avidity Biosciences common stock.
Avidity Biosciences, Inc. executive Teresa McCarthy, Chief Human Resources Officer, reported a mandated tax-related share sale. On January 7, 2026, she sold 1,965 shares of Avidity common stock at $72.23 per share. According to the disclosure, these shares were sold solely to cover tax withholding obligations arising from the vesting of restricted stock units (RSUs) on January 6, 2026.
The company’s equity incentive plan requires these tax obligations to be satisfied through a “sell-to-cover” transaction, and the filing states this was not a discretionary trade. McCarthy has an instruction letter in place for the automatic sale of such sell-to-cover shares, intended to satisfy the affirmative defense conditions of Rule 10b5-1. After this transaction, she directly beneficially owned 116,867 shares of Avidity common stock.
Avidity Biosciences, Inc. Chief Legal Officer John B. Moriarty reported an automatic sale of common stock tied to restricted stock unit (RSU) vesting. On January 7, 2026, 2,374 shares of common stock were sold at $72.23 per share to cover tax withholding obligations from RSUs that vested on January 6, 2026, under a required “sell-to-cover” arrangement in the company’s equity incentive plans. This was not a discretionary trade and was executed under an instruction letter intended to satisfy the affirmative defense conditions of Rule 10b5-1. After this transaction, Moriarty beneficially owned 74,557 shares of Avidity Biosciences common stock directly.
Avidity Biosciences Chief Financial Officer Michael F. MacLean reported an automatic sale of company stock related to equity compensation. On January 7, 2026, he sold 1,974 shares of Avidity Biosciences common stock at $72.23 per share, leaving him with 63,832 shares directly owned after the transaction.
According to the disclosure, these shares were sold solely to cover tax withholding obligations arising from the vesting of restricted stock units (RSUs) on January 6, 2026. The sale was executed as a mandated “sell-to-cover” transaction under the company’s equity incentive plans and was carried out under an instruction letter intended to satisfy the affirmative defense conditions of Rule 10b5-1, meaning it was not a discretionary trade by the CFO.
Avidity Biosciences, Inc. Chief Medical Officer Steven George Hughes reported a mandatory sale of company stock. On January 7, 2026, he sold 2,373 shares of common stock at $72.23 per share, leaving him with 36,494 shares held directly.
According to the disclosure, the sale was required to cover tax withholding tied to the vesting of restricted stock units (RSUs) on January 6, 2026. The company’s equity incentive plans mandate a “sell-to-cover” transaction for these tax obligations, and the filing notes this was an automatic, non-discretionary sale executed under an instruction letter intended to satisfy the affirmative defense conditions of Rule 10b5-1.
Avidity Biosciences, Inc. Chief Scientific Officer Michael W. Flanagan reported an automatic sale of common stock primarily to pay taxes on vested equity. On January 7, 2026, he sold 2,373 shares of Avidity Biosciences common stock at $72.23 per share. According to the disclosure, these shares were sold to cover tax withholding obligations arising from restricted stock units that vested on January 6, 2026, under a required “sell-to-cover” arrangement in the company’s equity incentive plans, and the transaction is described as non‑discretionary. After this sale, he beneficially owned 91,627 shares of common stock directly. The instruction letter for these sell-to-cover trades is intended to satisfy the affirmative defense conditions of Rule 10b5-1.
Avidity Biosciences outlines executive compensation changes and regulatory progress tied to its pending merger with Novartis. The board approved accelerating into December 2025 the payment of certain 2025 cash bonuses and the vesting and settlement of specified performance stock units for named executives and other leaders. These amounts are ones the executives would otherwise have received at closing of the merger or in 2026, and the company states the timing change is intended to address potential “excess parachute payment” issues under Sections 280G and 4999 of the tax code and to help preserve related tax deductions. Each affected executive signed an Accelerated Payments and Clawback Agreement that can require repayment if employment ends under certain conditions before the original payment dates or, for performance units, before December 31, 2029.
The company also reports that on December 17, 2025 the Federal Trade Commission granted early termination of the waiting period under the Hart‑Scott‑Rodino Antitrust Improvements Act for the Novartis transaction. The expiration of this waiting period satisfies one of the conditions to closing the merger and the related spin‑off of Atrium Therapeutics (SpinCo), while completion still depends on the SpinCo separation and other customary closing conditions described in its proxy materials.
Avidity Biosciences has agreed to be acquired by Novartis for $72.00 in cash per share, with Avidity becoming an indirect wholly owned subsidiary of Novartis after the merger. Stockholders will vote at a virtual special meeting on a merger proposal, a non-binding vote on merger-related executive pay, and a possible adjournment.
Before the merger closes, Avidity will separate its early stage precision cardiology programs into Atrium Therapeutics (SpinCo) and either distribute SpinCo to stockholders at one SpinCo share for every ten Avidity shares or sell SpinCo (or certain ROFN assets) to a third party and distribute the net cash proceeds pro rata, including to warrant and equity award holders. If the distribution occurs, Avidity will fund SpinCo with $270 million less its existing cash and securities, and SpinCo will operate as an independent public company.
Stockholders who do not vote for the merger and comply with Delaware law may seek court appraisal while still receiving any SpinCo shares or Permitted Sale Proceeds. The board unanimously recommends voting in favor of all proposals, and the transaction is subject to antitrust clearances, completion of the spin-off or permitted sale, and approval by a majority of outstanding shares.
Avidity Biosciences, Inc. is asking stockholders to approve its acquisition by Novartis AG, under which each share of Company Common Stock will be converted into the right to receive $72.00 in cash, subject to tax withholding. Before the merger, Avidity will separate its early-stage precision cardiology programs into a new company, Bryce Therapeutics, Inc. (SpinCo), and either distribute SpinCo stock at a ratio of one SpinCo share for every ten Avidity shares or sell SpinCo to a third party and distribute the cash proceeds pro rata. In the distribution scenario, SpinCo is expected to receive $270 million of funding (subject to adjustments) and operate as an independent public company. Avidity’s board unanimously determined the merger, spin-off and related agreements are fair and in stockholders’ best interests and recommends voting in favor of all proposals.