An investment firm raked in $730 million in a single day after making a huge bet on a biotech stock

• Investment firm Baker Bros. Advisors profited $730 million Monday after its stake in Seattle Genetics soared on positive drug news, according to Bloomberg data.
• The biotech company's tucatinib treatment surpassed expectations in a recent breast cancer study and improved the condition for patients whose cancer had reached their brains, the company said.
• Baker Bros. held a 29% stake in the company as of June 30, a position now worth about $5 billion after the positive drug news.
• Watch Seattle Genetics trade live here.

Investment firm Baker Bros. Advisors netted a $730 million profit Monday after its stake in Seattle Genetics shot through the roof on positive drug news, according to Bloomberg data.

Seattle Genetics traded as much as 18% higher Monday after a breast cancer study found its tucatinib treatment successfully countered the spread of cancer cells. The treatment posted better-than-expected improvements for patients whose cancer had reached their brains, the company said in a release.

Baker Bros. held a 29% stake in the biotech company as of June 30, according to Bloomberg, a position worth about $5 billion after the positive drug news. Seattle Genetics is the firm's largest holding.

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Seattle Genetics stock is up roughly 79% year-to-date. Its Monday peak of $101.95 per share was a record high for the stock.

The biotech company has 12 "buy" ratings, five "hold" ratings, and one "sell" rating, with a consensus price target of $90.13, according to Bloomberg data.

The company's consensus price target jumped nearly 5% after Monday's news prompted a series of upgrades.

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