SEATTLE ( TheStreet) -- Dendreon ( DNDN) reported third quarter Provenge sales of $20.2 million and forecast 2011 sales that are short of Wall Street's consensus estimates. Provenge, a prostate cancer immunotherapy, was launched in May but sales are constrained because Dendreon is operating a single manufacturing plant at less than full capacity and still building two others. Dendreon has told investors that about 2,000 patients would be treated with Provenge in the first 12 months of the launch and that manufacturing would reach full capacity in the middle of 2011. Dendreon said Wednesday it expects 2011 revenue in the range of $350 million to $400 million, with half of that to be generated in the fourth quarter. The new guidance is below the Street's current consensus revenue estimate of $402 million, which suggests either analysts are over-reaching or Dendreon is being conservative. The $20.2 million in Provenge sales for the third quarter fell about $4 million short of expectations, although monthly sales grew each month during the quarter and in October, Provenge sales were $9.5 million, the company said. Doctors have written about 1,000 prescriptions for Provenge since the drug was launched, the company added. That's double the number of Provenge prescriptions reported by Dendreon on its second-quarter conference call. "We’re pleased with the progress we have made in the first six months of the launch of Provenge," said Dendreon CEO Mitch Gold, in a statement. For the September quarter, Dendreon reported a net loss of $79.3 million, or 56 cents a share, which includes a charge for a litigation settlement equal to 9 cents a share. In the prior September quarter, Dendreon lost $45.6 million, or 40 cents a share. Dendreon shares closed Wednesday at $38.59 but were down 5% to $37 in the after-hours session. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com.