Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Good morning, fellow Foolish investors! Let's take a closer look at three companies -- Merck (MRK -0.11%), CytRx (NASDAQ: CYTR), and Mylan (MYL)-- which could loom large in health care headlines this morning.

Merck makes a $2.3 billion investment in Ablynx's oncology pipeline
First and foremost, Belgian biotech company Ablynx (NASDAQOTH: ABLYF) just signed a deal worth up to €1.7 billion ($2.29 billion) with Merck to develop new treatments for cancer.

This is the second major agreement between Ablynx and Merck, following a prior neurology partnership which started in October 2012. According to a statement from Ablynx, the company will be in charge of discovering antibody-derived proteins known as nanobodies, which are intended to target "immune checkpoint modulators". The theory is that Ablynx's nanobodies can help activate a patient's immune system to recognize and attack cancer cells.

Under the deal, Ablynx will be paid €20 million ($26.96 million) and €10.7 million ($14.42 million) in research funding during the initial three-year research term. Ablynx will be eligible to receive milestone payments up to €1.7 billion plus royalties, while Merck gets the rights to develop, manufacture, and commercialize any of Ablynx's approved products.

This is a positive development for Merck's oncology pipeline, which the company has been trying to grow under its new R&D chief Roger Perlmutter, who replaced Peter Kim last March.

Growing its small oncology portfolio into a new pillar of growth is critical for Merck, since it currently faces a simultaneous slowdown in sales of its top-selling asthma drug, Singulair, and its diabetes drug Januvia. Singulair lost patent protection in August 2012, while Januvia may be weighed down by safety concerns and rising competition in the field of alternative diabetes treatments. Last quarter, sales of Singulair plunged 53% year-over-year to $280 million, andsales of Januvia fell 5% to $927 million.

Merck's most promising oncology candidates are the skin cancer treatment MK-3475 and the ovarian cancer drug MK-1775, which it is co-developing with AstraZeneca.

CytRx's prices its new offering of 11.5 million shares
Meanwhile, CytRx could open lower this morning, after the company priced its previously announced public offering of 11.5 million shares at $6.50 per share. The sale will generate approximately $75 million in cash, prior to the deduction of underwriting discounts, commissions, and expenses.

The new offering price represents a 22% discount from the 52-week high of $8.35 the stock hit on January 30, and the 11.5 million shares will considerably dilute the 42 million outstanding shares of the stock.

Much of CytRx's previous rally of more than 200% over the past 12 months has been fueled by several positive developments regarding aldoxorubicin, the company's lead drug candidate. The drug is being tested as a second-line treatment for soft tissue sarcomas, and could eventually also be approved for first-line soft tissue sarcomas, brain cancer, and other indications. If approved for multiple indications, aldoxorubicin could generate peak sales of $1.1 billion -- a huge boost for a company with a market cap of $290 million with no stable sources of revenue.

CytRx's offering is necessary, since the company finished last quarter with only $23 million in cash and equivalents. Last October, the company added $24.1 million (after fees) from another equity offering, but the company's current cash position will be unclear until it reports its fourth quarter and full year earnings.

Mylan launches the world's first biosimilar version of Roche's Herceptin
Last but not least, generics maker Mylan announced that it had launched the world's first biosimilar version of Roche's (RHHBY -0.10%) blockbuster breast cancer drug Herceptin (trastuzumab) in India, known as Hertraz.

Hertraz is indicated for the treatment of HER2-positive metastatic breast cancer, which accounts for 15% to 20% of all breast cancer cases, and will be available in two strengths -- 440 mg and 150 mg.

Herceptin is one of the best-selling breast cancer drugs in the world, generating 6.08 billion Swiss francs ($6.67 billion) in 2013 sales. However, Roche abandoned its Herceptin patent in India in August 2013, due to the intellectual property rights "environment" in the country.

Over the past several years, the Indian government has invalidated patents for drugs that it considers essential for the poor -- such as cancer medications -- and handed over the production rights to local generic manufacturers instead.

Where Roche retreated Mylan sees opportunity. In fiscal 2012, Roche reported $21 million in Herceptin sales in India. It's unclear how much Mylan will lower the price, but Roche has already lowered the price of Herceptin to $1,366 per month (compared to $4,500 per month in the U.S.).

This is the second recent positive development for Mylan in India. On January 31, the company was named Gilead Sciences' exclusive branded medicines business partner in India, which will allow Mylan to market and distribute Gilead's HIV drugs Viread (also for hepatitis B), Truvada, Stribild, and the systemic fungal infection treatment AmBisome.