Let's take a quick look at three stocks -- Puma Biotechnology (NASDAQ:PBYI), Biogen Idec (NASDAQ:BIIB), and Intuitive Surgical (NASDAQ:ISRG) -- which could all loom large in health care headlines this Wednesday morning.

Puma Biotechnology soars on positive breast cancer data
Shares of Puma Biotechnology are up more than 240% in pre-market trading this morning, after the company reported that a clinical trial of its experimental drug neratinib blocked the return of breast cancer in women with early stage HER2-positive breast cancer. These patients, who account for roughly 20% of all breast cancer cases, are traditionally treated with Roche's Herceptin.

During a trial of 2,821 women, neratinib improved disease-free survival by 33% compared to the placebo. The women in the trial had breast cancer removed surgically, and were then treated by Herceptin to prevent recurrence. After the Herceptin treatment, the patients were either given neratinib or a placebo. Based on these positive results, Puma intends to seek U.S. regulatory approval in the first half of 2015. Neratinib, which is Puma's only pipeline candidate, is also in eight other clinical trials for various types of breast, lung, and other cancers.

Citigroup, which raised its price target for Puma from $99 to $292, now believes that Puma could be a takeover target. Citi believes that the company could be worth $291 to $351 per share in a takeover scenario.

These are highly positive developments for Puma, but investors shouldn't overlook a negative development -- Pfizer just amended its license agreement with Puma for neratinib. Under the terms of the new amendment, Pfizer will no longer fund legacy clinical trials for the drug. The royalty rate will also be decreased to the low to mid-teens, compared to the original range of 10% to 20%. As a result, Puma expects its R&D expenses to rise by $30 million, with most of the expenses occurring in 2014.

Biogen climbs after topping analyst forecasts
Shares of Biogen Idec are up more than 6% in pre-market trading this morning after the company reported impressive second quarter earnings. Biogen's non-GAAP earnings climbed 52% year-over-year to $3.49 per share, topping analyst estimates by $0.65. Revenue rose 40% to $2.4 billion, topping estimates by $280 million.

Tecfidera, Biogen's oral MS treatment, was the main growth leader. Sales rose 264.5% year-over-year to $700 million. The drug launched in April 2013, and is expected to generate peak annual sales of $3.8 billion, according to EvaluatePharma. Tecfidera competes against Novartis' Gilenya and Sanofi's Aubagio. Sales of Tysabri, Biogen's older infused MS treatment, climbed 37.9% to $533 million. Sales of Avonex, another older injectable MS drug, remained flat at $774 million.

Biogen also updated its full year 2014 guidance. The company expects revenue to rise 38% to 41%. Non-GAAP diluted earnings are expected to come in between $12.90 to $13.10 per share -- representing 44% to 46% growth from 2013. Biogen also revised its GAAP earnings expectations from $9.85-$9.95 to $11.26-$11.46 per share. Shares of Biogen have climbed nearly 32% over the past 12 months.

Intuitive Surgical climbs on better-than-expected sales and shipments
Intuitive Surgical is up nearly 13% in pre-market trading, despite posting its fifth consecutive quarterly earnings decline. The maker of the da Vinci non-invasive surgical robot reported a net profit of $2.77 per share -- a 29% decline from the prior year quarter. Revenue fell 11% year-over-year to $512.2 million, but topped Wall Street's lower expectations of $501.7 million.

Intuitive Surgical sold 96 da Vinci systems during the quarter, a sharp decline from 143 a year earlier, but a moderate sequential improvement from 87 last quarter. Sales of the da Vinci, which costs $1.5 million each, have fallen due to reduced hospital budgets and a flurry of safety concerns which started with an FDA probe last year.

Sales of instruments and accessories, which are dependent on da Vinci sales, fell about 1% to $262 million. However, procedures utilizing da Vinci systems climbed roughly 9%, thanks to higher usage for general surgery in the U.S. and urologic procedures in overseas markets.

Based on its moderate improvements during the quarter, Intuitive raised the low-end of its full year procedure forecast from 2%-8% growth to 5%-8% growth. The company did not provide a full-year revenue forecast, due to various uncertainties about the market. The stock has remained flat over the past 12 months, despite a few volatile spikes.