(Reuters) - Celgene Corp on Thursday reported third-quarter sales of its key psoriasis drug Otezla that badly missed expectations and significantly scaled down its 2020 targets for product sales and earnings, sending its shares tumbling 18 percent.

FILE PHOTO: Celgene Executive Chairman Robert Hugin takes part in a panel discussion titled "Accelerating Medical Research" at the Milken Institute Global Conference in Beverly Hills, California April 27, 2015. REUTERS/Mario Anzuoni

Celgene, which also missed estimates for quarterly revenue, has seen it shares lose about 30 percent of their value in October alone.

Investors have been concerned about patent challenges to its long-time cash cow Revlimid for multiple myeloma and the surprise failure last week of an experimental Crohn’s disease drug touted as a future multibillion-dollar product.

Celgene shares fell by $23.23, or 19 percent, to $96.33. The stock’s decline was the biggest drag on the benchmark S&P 500 equity index and the Nasdaq index.

The company said it would initiate immediate share repurchases from $3.8 billion remaining on its authorization.

Celgene leadership did not attempt to sugarcoat the situation, but highlighted future pipeline opportunities with a dozen pivotal data readouts expected by the end of 2018.

“We’re very disappointed with the results of the quarter and are committed to rebounding very quickly with respect to Otezla and our overall performance,” Chief Executive Mark Alles said, adding the Crohn’s drug failure was “a major disappointment.”

Otezla sales of $308 million in the quarter missed analyst estimates by over $100 million. The company blamed slowing growth in both the psoriasis and psoriatic arthritis markets in the U.S. due to reimbursement challenges from insurers.

The “Otezla miss is the biggest story of the quarter,” RBC Capital Markets analyst Brian Abrahams said.

The biotechnology company lowered its full-year Otezla sales forecast to $1.25 billion, from a range of $1.5 billion to $1.7 billion.

For 2020, Celgene lowered its adjusted earnings forecast to greater than $12.50 per share from greater than $13.00.

It slashed its 2020 oncology sales forecast to a range of $1 billion to $1.1 billion, from its prior projection of at least $2.2 billion, suggesting possible concerns about growth of Pomalyst and Abraxane.

Long-range targets for inflammation and immunology sales were cut to $2.6 billion to $2.8 billion, from greater than $4 billion, reflecting continuing Otezla challenges and the disappearance of GED-0301, the once-promising Crohn’s drug.

Celgene signaled high hopes for its experimental multiple sclerosis drug ozanimod, with key data imminent. It also said it would test the medicine for Crohn’s, citing a large unmet need in irritable bowel diseases.

Revlimid sales for the quarter rose 10 percent to $2.08 billion, shy of analyst estimates of $2.11 billion. But the company maintained its 2017 forecast of up to $8.3 billion.

Total revenue rose nearly 11 percent to $3.29 billion, short of analyst’ estimates of $3.42 billion, according to Thomson Reuters I/B/E/S.

Excluding items, Celgene earned $1.91 per share, topping analysts’ average forecasts by 4 cents with help from cost controls. It also raised the low end of its 2017 adjusted profit forecast by 5 cents and now expects $7.30 to $7.35 per share.

Despite the failure of GED-0301, which came to Celgene via acquisition, the company said it would continue aggressive business development efforts.

Executive chairman and former CEO Robert Hugin promised “to turn this adversity into opportunity.”

“There’s nothing fundamentally wrong with Celgene,” he said.