ABA Model Rule 3.6
The rule lets a lawyer state the claim or defense, the identity of the people involved, information in a public record, that an investigation is in progress, and the scheduling or result of any step in the litigation. It also allows a limited statement needed to protect a client from the undue prejudicial effect of recent publicity the lawyer did not initiate. Most states have adopted it with modifications.
See Litigation PR: Best Firms, Costs and Rules and What Lawyers Can Actually Say.