(Reuters) - Spectrum Pharmaceuticals Inc said on Friday the U.S. Food and Drug Administration had rejected the drugmaker's bladder cancer treatment, apaziquone.

The company said it was considering a new smaller study for the drug, that would replace an ongoing late-stage study, in which patient enrollment has been stopped. (http://bit.ly/2g380hh)

Apaziquone is being developed to treat non-muscle invasive bladder cancer, also known as early bladder cancer, which accounts for about 80 percent of all bladder cancers.

In September, an advisory committee to the FDA unanimously voted against Spectrum's drug candidate, saying it was not effective in delaying the time it takes for the disease to recur. Spectrum's shares have fallen 22 percent since then, up to Thursday's close.

Some 80 percent of patients with bladder cancer experience a recurrence of the disease within five years, many within two years.

Most bladder cancers are treated with surgery, either alone or with other treatments. Surgery can often remove early stage bladder tumors, but new tumors frequently form in other parts of the bladder.

Henderson, Nevada-based Spectrum, which also develops other cancer drugs, reported a 16.6 percent rise in third-quarter revenue on Monday, helped by strong demand for its colon and blood cancer treatments.

(Reporting by Dipika Jain in Bengaluru; Editing by Sai Sachin Ravikumar)