Malcolm Gets has left the cast of The Threepenny Opera at San Francisco's American Conservatory Theatre, to be replaced as Macheath by Philip Casnoff, best known for his leading role in Chess. An ACT spokesperson said Gets left for personal reasons.

Co-stars Bebe Neuwirth and Nancy Dussault are still with the show, which also features Lisa Vroman as Lucy Brown and Anika Noni Rose as Polly. Performances begin Sept. 2 for an opening Sept. 8 and a run through Oct. 10. Opera begins the ACT season, which will then continue with the premiere of David Hirson's Broadway-bound comedy, Wrong Mountain.

Carey Perloff, artistic director of ACT, directs The Threepenny Opera, which features choreography by Luis Perez, a former Joffrey Ballet Company member.

Neuwirth, an alum of the Broadway revivals of Chicago, Damn Yankees and Sweet Charity (and TV's "Cheers") gets the choice role of Jenny Diver in the landmark 1928 musical by Bertolt Brecht and Kurt Weill. The jazz-flecked yarn based on John Gay's The Beggar's Opera (1728), weaves a tale of lusty passion and political corruption and features classic songs such as "The Ballad of Mack the Knife," "Pirate Jenny" and "Tango Ballad."

Dussault, who appeared on Broadway in Do Re Mi, Bajour, Side by Side by Sondheim and as one of the witches in Into the Woods, became known for her role as Muriel on TV's "Too Close For Comfort." She'll play Mrs. Peachum opposite ACT actor Steven Anthony Jones as Mr. Peachum. The 22-member third-year class of the ACT master of fine arts program will form the Threepenny ensemble.

The Threepenny Operawill be presented at the Geary Theatre. Official opening is Sept. 8; single tickets go on sale Aug. 23. For information, call (415) 749 2228.

-- By David Lefkowitz & Kenneth Jones