Medicare officials are debating whether the agency should cover a new prostate-cancer treatment

 that costs $93,000 per patient, sparking criticism from Dendreon Corp. investors and patient advocacy groups who earlier pushed the Food and Drug Administration to approve the novel therapy.

A Medicare advisory panel is set to meet Wednesday to discuss Dendreon’s Provenge treatment, following criticism from shareholders and some patient advocacy groups that the government might be trying to ration high-priced care.

Medicare usually covers FDA-approved medicines without much debate, but in June the federal Centers for Medicare & Medicaid Services said it would undertake a national review of Provenge. That prompted a flood of public comments. Medicare has done national reviews of only four cancer-related drugs, according to the agency.

Last week, a government health agency that studied Provenge on Medicare’s behalf found only “moderate” evidence that it works. In the clinical trial that led to FDA approval, median survival on Provenge was a little more than two years, or four months longer than patients in the control group.

Medicare’s decision is critical for late-stage patients and for Dendreon, because some 70% of men who would likely be eligible for Provenge are covered by the federal program. More than 200,000 Americans are likely to be diagnosed with prostate cancer this year, and about 32,000 will die of the disease, according to the American Cancer Society.

Two senators have weighed in on the issue. Sen. John Kerry (D., Mass.), who was treated for prostate cancer in 2003, and Sen. Arlen Specter (D., Pa.), a cancer survivor, wrote to the Medicare agency in August demanding an explanation for why the agency wanted the review. They expressed concern it would “limit access” to the treatment.

In September, Dendreon hired a leading Washington lobbying firm, the Glover Park Group, for “engaging Congress” on the company’s research, according to Senate records. Glover Park didn’t respond to requests for comment. A Dendreon spokesman declined to comment.

Provenge isn’t a typical drug, but a multistep approach in which a patient’s blood is sent to a Dendreon lab where it is processed with biological additives that help the patient’s immune system fight the cancer. Because it seeks to harness immune reactions, Provenge is sometimes called a cancer vaccine, but it is different from common vaccines that prevent infectious diseases such as the flu.

The FDA initially declined to approve Provenge in 2007. That sparked protests outside the agency and nationwide. After Dendreon did another study, the FDA approved Provenge in April this year. But the approval was only for late-stage prostate cancer patients whose disease has metastasized. Provenge supporters believe it deserves wider, off-label use.

Ted Cohen, a Dendreon investor, in 2008 sent a funeral bouquet to the FDA’s then-commissioner to signal his mourning for the drug’s initial rejection. Mr. Cohen blamed hedge funds betting on a decline in Dendreon’s stock price and conflicts of interest among government medical experts. Like other Provenge supporters, Mr. Cohen noted in an interview that Medicare’s rules don’t permit it to weigh the cost of a drug versus effectiveness, although some outside specialists said the advisory panel could discuss the price tag. The Medicare review is “an excuse to make Dendreon and its revolutionary treatment for end-stage prostate cancer the ‘poster boy’ for everything it claims is wrong with the pharmaceutical industry today,” he said.

The flood of comments to Medicare also includes some from Provenge critics. The law firm Willkie Farr & Gallagher LLP submitted a 26-page anonymous scientific analysis contending the data show the treatment may do more harm than help by weakening patients’ immune systems. The firm’s submission said it couldn’t name the author “because of the public vilification of anyone that questions Provenge.” A Willkie lawyer said the firm was acting on behalf of a client with a financial interest.

An activist group supporting Provenge called Care to Live in October announced a $500 reward “for comprehensive information leading to the confirmed identification of the person” who anonymously emailed doctors this summer to “disparage” Provenge.

The lawyer for Care To Live, Kerry Donahue of Bellinger and Donahue in Ohio, said in an interview that although Care To Live’s proponents are assertive, they only put up the bounty to learn the name of the email writer, “because people were shorting Dendreon,” and Provenge critics’ motivations need to be exposed.

Sean Tunis, a former Medicare chief medical officer, said he expects Medicare will ultimately pay for Provenge, but not for the unapproved uses. Dr. Tunis said Medicare is likely to shy away from a head-onbattle over cost after the bruising health-care debate over the past year, which included allegations that Democrats wanted to ration care. “This is not the time, politically, for level-headed discussion on whether four extra months is a good outcome,” he said.