“If you have faith, then it must be true,” says the man who has just extracted slimy gobbets of flesh from a woman’s abdomen with his bare hands and no incision. The gobbets, he says, are disease-causing “negativities,” though we know they are actually chicken guts marinated in fake blood.

Faith and faithlessness — in healers, in countries and even in art forms — are the ideas animating “Felix Starro,” an earnest world-premiere musical by the novelist and playwright Jessica Hagedorn (book and lyrics) and the composer Fabian Obispo (music). The Ma-Yi Theater Company production that opened on Tuesday at Theater Row is said to be the first musical by Filipino-Americans ever presented Off Broadway.

That’s no small thing, if the form is to keep from shrinking into a souvenir of itself. And there is much to like about a work that brings the tropes of classic musicals to a story about people usually ignored by them. But you may also find yourself wondering whether those time-tested techniques are really capable of doing justice to a story so unlike the ones for which they were devised.

That there are two title characters is emblematic of the opportunity and the problem. One Felix Starro is the faith healer himself (Alan Ariano): a man of about 70, once famous in his native Philippines for his “hands of power.”