Avidity Biosciences (RNA) investor relations material

Executive summary

• Special meeting of stockholders was convened and immediately adjourned to February 26, 2026, to allow more time to satisfy conditions for a planned distribution and merger.

• The distribution of Atrium Therapeutics, Inc. (SpinCo) shares to stockholders is a condition for closing the merger with Novartis, expected to occur on February 27, 2026.

• Stockholders who have already registered or submitted proxies do not need to take further action unless they wish to change their vote.

• The record date for voting remains January 29, 2026, and previously submitted proxies will be valid for the reconvened meeting.

• Forward-looking statements highlight risks and uncertainties regarding the completion and benefits of the transactions.

Voting matters and shareholder proposals

• Stockholders are being asked to approve the distribution and merger, both subject to closing conditions outlined in the proxy statement.

• Proxies previously submitted will be counted at the reconvened meeting unless revoked.

• Stockholders are encouraged to vote promptly if they have not already done so.

Board of directors and corporate governance

• Certain directors and executive officers are participants in the solicitation of proxies and may have interests in the transaction that differ from other stockholders.