SEATTLE ( TheStreet) -- Dendreon ( DNDN) troubles, already substantial, just got so much worse.

Sales of the prostate cancer therapy Provenge fell short of the Street's second quarter expectations. The company now says Provenge sales will no longer grow year over year, as expected. Lastly, Dendreon's CFO Greg Schiffman announced his exit from the company at the end of the year.

The deluge of bad news, delivered during Dendreon's second-quarter earnings announcement Thursday night, is sure to raise even more concerns about the company's viability.

Dendreon shares closed Thursday down 1.5 percent to $4.59 but fell another 12 percent to $4.09 in after-hours trading.

Provenge sales in the June quarter totaled $73.3 million, or 8 percent quarter-over-quarter growth, versus Street consensus of $75 million, or 11 percent growth.

Based on patient enrollment trends this summer, Dendreon now say it doesn't expect Provenge sales growth to increase enough to meet its guidance of sales growth for the full year. Provenge use is being negatively impacted by competing prostate cancer drugs marketed by Johnson & Johnson ( JNJ - Get Report) and Medivation ( MDVN), respectively.

For the first six months of the year, Provenge sales totaled $141 million and the Dendreon would have needed sales of $184 million in the third and fourth quarters. Thursday, the company said such sales growth is unlikely.

If there's any consolation to the disappointing retreat in Provenge guidance, it's that the Street didn't believe the company anyway, already expecting year over year sales to fall by 3 percent.

Dendreon ended the second quarter with $280.6 million in cash. Looming ahead is $545 million in convertible debt due in 2016.

Net loss in the second quarter was $68.8 million, or 45 cents per share, compared to a net loss of $96.1 million, or 65 cents per share, for the same period in 2012.

-- Reported by Adam Feuerstein in Boston.

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