SORRENTO VALLEY -- Troubles at two biotech companies are resulting in 220 layoffs.

Nanogen Inc. said it is requesting bankruptcy court approval to sell its assets for $25.7 million to The Elitech Group, a French diagnostics company. Nanogen is laying off 89 workers, according to state data.

Separately, Arena Pharmaceuticals Inc. said it is laying off 130 of its 400 employees in the region. Most of the cuts took effect April 23, with the remainder following by June 22, spokeswoman Cindy McGee said.

Several biotechs in the last year have said financing difficulties forced cuts. McGee said success in preliminary testing of Arena's Lorcaserin anti-obesity drug in March did not boost Arena's shares from the $4 range, which would have made it easier to raise money.