Shares of Arena Pharmaceuticals (ARNA) - Get Report were down about 16% to $1.22 in midday trading on Tuesday, after a secondary offering from the San Diego biotech failed to impress.

The company said last night said it had priced an underwritten public offering of 60 million shares at a price to the public of $1.15 apiece, which would generate gross proceeds of $69 million before deducting the underwriting discounts and commissions and offering expenses.

The company said it has given underwriters a 30-day option to buy up to 9 million additional shares. Arena said it anticipates to use net proceeds from the offering for clinical and preclinical development of drug candidates,  as well as for general corporate purposes and for capital expenditures.

Meanwhile, shares of Rigel Pharmaceuticals (RIGL) - Get Report were up nearly 6% to $3.36 in premarket trading Tuesday. The South San Francisco, Calif.-based firm after the market close on Monday announced its new drug application submission to the U.S. Food and Drug Administration for fostamatinib in patients that have chronic and persistent immune thrombocytopenia.

Shares of Rigel have since retreated and traded around $3.13 midday Tuesday, down about $1.10 apiece.

Among the other biotech stock movers was Cytokinetics (CYTK) - Get Report , whose shares were up 10% to $12.25.