Dendreon Corporation reported weaker-than-expected demand for its prostate cancer treatment Provenge as it began the year, sending the company’s shares down as much as 20 per cent. Dendreon, which has taken investors on a roller-coaster ride since the treatment was approved in 2010, reported unexpectedly high sales of Provenge in the fourth quarter, but the company said on a conference call with investors on Monday that $2 million to $3 million of those sales would normally have been recorded in January. The company last month reported better-than-expected fourth-quarter gross sales of Provenge of $82 million, up from $66 million in the third quarter. That news sent Dendreon’s shares up as much as 55 per cent. “You saw pretty strong demand in the fourth quarter, so people expected stronger demand in first quarter,” said Salveen Richter, an analyst at Collins Stewart. “Now people are wondering about the longer-term trajectory.” John Johnson, the company’s new chief executive, said physicians had concentrated some of their treatments around year end, indicating the sales growth seen in December cannot be sustained. The company forecast low-single-digit growth in the first quarter compared with the fourth quarter, and said it expects modest quarterly sequential growth throughout the year. “We had a softer order book coming into the year, but we have strengthened through the quarter,” he said. Dendreon posted fourth-quarter net income of $38.1 million, or 26 cents a share, compared with a net loss of $91.8 million, or 64 cents a share, in the year-ago period. Net product sales were $77 million, compared with $25 million a year earlier The fourth-quarter results included a payment of $125 million associated with the sale of a royalty interest. Mark Schoenebaum, an analyst at ISI Group, said investors should not be surprised at on Monday’s results. “We already knew that December sales were much higher than expected, and most observers suspected that the December growth rate was not sustainable,” he said in a research note. Dendreon executives told analysts that one of their prime goals is to reduce their cost of goods sold from the current level of more than 70 per cent. In addition to increasing revenue, the company expects to increase automation to help achieve greater manufacturing facilities.