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Good morning, fellow Foolish investors! Let's take a look at three health care stocks you should be following this morning: Cell Therapeutics (NASDAQ:CTIC), Aratana Therapeutics (NASDAQ:PETX), and TherapeuticsMD (NYSEMKT:TXMD).

Cell Therapeutics gets a NICE vote of confidence
Let's first take a look at Cell Therapeutics, which announced yesterday that the National Institute for Health and Care Excellence, or NICE, in the U.K. had issued a Final Appraisal Determination, or FAD, for its blood disorder drug Pixuvri.

NICE's draft guidance determined that Pixuvri was a cost-effective treatment for adults with multiply relapsed or refractory aggressive B-cell non-Hodgkin lymphoma, or NHL. There were an estimated 1,600 to 1,800 cases of the rare blood disorder in the U.K. last year.

In May 2012, Pixuvri was granted a conditional marketing approval in the E.U. as a monotherapy for the same indication. However, it has not been determined if Pixuvri is effective as a fifth line or greater chemotherapy for refractory patients. Pixuvri is not approved in the United States, but it is being tested as a combination treatment with Roche's Rituxan/MabThera, a common treatment for diseases with B-cell disorders like NHL.

Sales of Pixuvri, the company's only source of revenue, only came in at $0.4 million last quarter. However, analysts believe that annual peak sales could eventually hit $240 million if it is approved in other markets, and the NICE FAD suggests Cell is headed in the right direction.

This positive step for Pixuvri is a second recent catalyst for the company, which announced last week that the FDA had removed the partial clinical hold on its experimental cancer drug tosedostat, which was in phase 1/2 trials. The hold was initiated in June after a patient in the trial died.

Although these two developments are highly positive, investors should be advised that Cell Therapeutics already rallied more than 70% over the past 12 months and trades with a whopping P/S ratio of 220.

Aratana acquires Okapi Sciences
Meanwhile, Aratana Therapeutics, a company focused on pet medications, today announced its acquisition of Okapi Sciences, which has a proprietary pet antiviral platform and five clinical and development stage candidates in its pipeline. Two of Okapi's most promising antiviral products include its feline herpes and feline immunodeficiency virus franchises.

The acquisition was made for approximately $14 million in cash, a promissory note for $15 million with a maturity date of Dec. 31, 2014, and a possible additional payment of $16 million in cash or shares of common stock.

Aratana, which I identified in a previous article as one of the top-performing biotech IPOs of 2013, has no marketed products. However, it announced that it had met all of its 2013 milestone developments in late December -- a clinical study for its osteoarthritis drug for dogs showed promising results, it initiated a study with 150 dogs for its appetite-stimulating drug, and outlined plans for a field study for its drug for postoperative pain in dogs.

Aratana also acquired Vet Therapeutics in October to add veterinary biologics to its pipeline. The combined acquisitions of Vet and Okapi could significantly accelerate the speed at which Aratana's products reach the market, so investors should stay tuned to the company's progress.

TherapeuticsMD provides an update regarding REPLENISH
Last but not least, TherapeuticsMD, a women's health care company, provided an update regarding its phase 3 trial for TX 12-001HR, an experimental treatment for menopause symptoms.

TherapeuticsMD has now completed its 50th site enrollment for the double-blind, placebo-controlled trial, known as REPLENISH. REPLENISH will measure the reduction in the frequency and severity of hot flashes over a 90-day period while checking endometrial protection for a year.

TX 12-001HR is one of the company's four main hormone therapies. According to a study commissioned by the company, the current market for hormone therapies is estimated to be worth over $3.7 billion per year.

TX 12-001HR stands out from other hormone therapies because it is the first and only bioidentical low-dose HRT (hormone replacement therapy) combo. This means it contains two equal low doses of the hormones 17ß-estradiol and progesterone, which is considered a superior option to the current market of "compounded" (customized) menopausal drugs.

If approved by 2016, analysts believe TX 12-001 could generate peak sales of $300 million -- hardly a blockbuster, but not a bad boost for a company that only reported $3.8 million in revenue in fiscal 2012.

Another top stock to watch
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Fool contributor Leo Sun has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.