Dendreon Corporation (DNDN), Merrimack Pharmaceuticals Inc (MACK), Novavax, Inc. (NVAX): Three Horrendous Health-Care Stocks This Week

August might be hot for most of the country, but the first full week of the month wasn’t so hot for some stocks. Here are some of the most horrendous performers across all of health care for the past week.

Poor Provenge
Dendreon Corporation (NASDAQ:DNDN) tried to spin its second-quarter financial results as positively as it could. The market wasn’t buying the spin, though. Shares for the pharmaceutical company plunged 26% for the week.

The problems stem from prostate cancer drug Provenge. While second-quarter sales picked up compared with the previous quarter, they were still down 8.3% year over year. As a result, Dendreon Corporation (NASDAQ:DNDN)’s net loss of $0.45 per share missed the average analysts’ estimate of a $0.42-per-share loss.

Management pointed to as many positives as they could, including a positive opinion from Europe’s Committee for Medicinal Products for Human Use and highest-ever sales in urology. Those positives weren’t enough to overcome the stark financial reality that sales for Provenge will still fall in 2013 from 2012 levels.

A miss, and two on the way
Robert Mulroy, CEO of Merrimack Pharmaceuticals Inc (NASDAQ:MACK), said his company was “pleased with a strong quarter of progress” in the press release announcing second-quarter results. Investors weren’t as pleased. Shares fell 9% this week, with most of the drop occurring after the second-quarter update was announced.

Merrimack Pharmaceuticals Inc (NASDAQ:MACK) reported a net loss for the quarter of $0.31 per share. Analysts expected a loss of $0.28 per share. That miss only partially explained investors’ disappointment. Merrimack Pharmaceuticals Inc (NASDAQ:MACK) also reported some negative news with one of its clinical studies.

The company, along with development partner Sanofi SA (ADR) (NYSE:SNY), has several studies under way for cancer drug MM-121. Merrimack Pharmaceuticals Inc (NASDAQ:MACK) said that interim review of two of those studies, one in ovarian cancer and another in wild type non-small-cell lung cancer, suggested that primary endpoints would not be met. These setbacks probably affected the stock more than the earnings miss did.