NEW YORK (TheStreet) -- Shares of Conatus Pharmaceuticals (CNAT) - Get Conatus Pharmaceuticals Inc. Reportwere surging 22.85% to $2.15 on heavy trading volume late Tuesday morning after drug maker Allergan (AGN) said it would acquireTobira Therapeutics (TBRA) for up to $1.695 billion.

Allergan will pay $28.35 per share for the biotechnology company, or up to $49.84 per share pending certain development, regulatory and sales goals.

The minimum deal price represents a 500% premium over Tobira's closing price yesterday of $4.74 per share.

Like Tobira, Conatus is developing several treatments for non-alcoholic steatohepatitis (NASH), a fatty liver disease.

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More than 6.65 million shares of Conatus, a San Diego-based biotechnology company, have traded hands so far today vs. the 30-day average volume of about 268,000 shares.

Shares of Allergan were sliding in late morning trade while Tobira stock was spiking 715.08% to $38.63, over 9.93 million Tobira shares trading vs. the 30-day average volume of about 400,000 shares.

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