Marvel reportedly has granted its fifth rights extension to the producers of Spider-Man: Turn Off the Dark, the much-delayed Broadway musical.

According to Variety, the big-budget production appears to be moving full steam toward an opening in November or December ... a mere eight months or so behind schedule: A flying workshop was held last week in Las Vegas, green-screen footage is being filmed this week in New York City, and construction continues on the 1,700-seat Hilton Theatre -- all sure signs the $52-million production is back on track.

That's certainly a good thing for the Julie Taymor-directed show, as the trade paper points to indications that Marvel is getting antsy: "It's said Marvel has periodically asked for proof of the project's progress, with some adding that the recent fifth extension would likely be the last."

Word trickled out last week that Next to Normal star Jennifer Damiano has been cast as Mary Jane Watson, replacing Evan Rachel Wood, who left the production in March. Spider-Man producers haven't confirmed Damiano's casting or commented on widely circulating reports that Patrick Page (The Lion King) will play Green Goblin, stepping in for Alan Cumming, who bailed in April. At this point, the only cast member known for certain is 26-year-old relative newcomer Reeve Carney, who'll star in the title role.

Featuring a score by U2's Bono and the Edge with a book by Taymor and Glen Berger, Spider-Man: Turn Off the Dark is expected to be the most expensive musical in Broadway history.