SpeakEasy’s latest Boston premiere is a musical built around the unproduced songs of Edward Kleban, whose only Broadway credit was the show he won a Tony for — A Chorus Line, for which he furnished the lyrics to Marvin Hamlisch’s music. Written by Lonny Price and Kleban’s companion Linda Kline, the book of A Class Act is a loose biography of Kleban, who died of cancer in 1987. (A Chorus Line was still running in New York at the time, 12 years after its inception.) Kline and Price suggest a number of reasons for Kleban’s one-hit-wonder status: a raft of insecurities and phobias, a tendency to interfere in the production of every show he had a hand in, an insistence on writing tunes as well as lyrics — which, according to this version, prevented him from revisiting his phenomenally successful collaboration with Hamlisch. None of these speculations is convincing, however, because the show itself is clunky, its characters are cardboard, and its structure is a collection of forced, increasingly maudlin encounters between Kleban and his friends, most of them his fellow students in Lehman Engel’s BMI songwriting workshop, where his songs were first performed.

The musical is set at a memorial for Kleban; the testimony of his friends and associates is intercut with flashbacks to his life. The idea is that Ed (Jon Blackstone), a ghost listening to the eulogies about him, is still such a micro-manager that he insists on correcting everybody’s mistakes by providing the context omitted by the speeches in his honor. Paul Daigneault, the director of the SpeakEasy production, never finds a tone for this conceit (it isn’t comic, though you’d think it would be), or for the gathering of the mourners (which is alternately bitchy and bathetic). But it’s not entirely his fault. The script is sparse, trite, and homiletic (sample dialogue: " You can’t change women like you change keys " ), and it lacks a dramatic build; Kline and Price simply pile one scene on top of another. I didn’t buy Ed’s ongoing relationships with his BMI buddies, even though they descend en masse on the Toronto opening of his first show, or his attachment to the childhood sweetheart (Kerry Dowling) he never gets over and to whom he runs whenever he has a crisis. She’s become an oncologist, so — in one of the most embarrassing book scenes in any recent musical — it’s she who diagnoses his illness.

Worse, the songs don’t make the case that Broadway lost any masterpieces when Kleban provided no follow-up to A Chorus Line. One witty number called " Broadway Boogie Woogie " (deftly performed by Leigh Barrett, as Lucy, the Linda Kline character) chronicles the disappointments of a working musical-comedy actress. It’s placed cleverly at his audition for Michael Bennett (Will McGarrahan), A Chorus Line’s creator, so you believe that Bennett might have hired Kleban on the basis of this knowing, sardonic survey of the professional scene. The first song Ed presents at the workshop, " Paris Through the Window, " is rather wan but has a youthful charm. The others are mediocre at best; some of the lyrics fall far short of mediocrity. (Try " You are now entering Mona/Population: two, " or " Let’s have a joke/I’m going broke/Watching your eyes. " )

The cast work hard to persuade you that they’re performing a class musical; the singing is fine (especially Barrett’s and Dowling’s), and the impersonations — McGarrahan’s of Michael Bennett, Joe Siriani’s of Lehman Engel, Andrew Miramontes’s of Marvin Hamlisch — are playful. But up against woefully inferior material, the actors work too hard, especially Jon Blackstone, who buries his character under a thousand affectations and performs every song with the melodramatic fervor of an 11 o’clock number like A Chorus Line’s " What I Did for Love. " Given the format — four men and four women moving in and out of a series of sketches and songs that can’t be teased into anything more substantial — a more relaxed style would have served the show better.