The biotech analysts at PropThink always try to handicap the best and worst scenarios on the stocks they cover. PropThink is an intelligence service that delivers long and short trading ideas to investors in the health care and life sciences industries. Their focus is on identifying and analyzing technically complicated companies and equities that are grossly overvalued or undervalued.

Here are some current stocks the PropThink analysts are covering. Investors should remember that these names can be highly speculative and are not suitable for conservative portfolios.

AVEO Pharmaceuticals Inc. (NASDAQ: AVEO) may be a micro-cap stock to buy. An advisory panel vote went against the company recently, but it may be a bottom-fishing candidate. Aveo is a developmental stage biotech company, with its leading product candidate designed to treat renal cancer. Seth Klarman’s Baupost Group hedge fund owned 4.9 million shares at the beginning of this year. The Thomson/First Call price target is $2.90.

Onyx Pharmaceuticals Inc. (NASDAQ: ONXX) is a company with huge momentum. For its most recent quarter, Onyx delivered a doubling in revenue from the previous year to $145.5 million, with practically all the gains coming from its multiple myeloma drug Kyprolis. The consensus price target for the stock is $106.

Celgene Corp. (NASDAQ: CELG) hit a new 52-week high this week. The company recently reported data from its ongoing phase III trial of apremilast this month, showing the drug successfully reduced psoriatic arthritis symptoms by at least 20% versus placebo. The consensus target is at $140.

Regeneron Pharmaceuticals Inc. (NASDAQ: REGN) is another name that has been on a huge roll. Regeneron is an integrated biopharmaceutical company that focuses on development of new candidates for serious ailments primarily in areas like ophthalmology, inflammation, cancer and hypercholesterolemia. The consensus for the stock is at $288.50.

MAKO Surgical Corp. (NASDAQ: MAKO) is an intriguing stock to the PropThink team, although not yet listed as a stock to buy. MAKO Surgical is a medical device company that markets its advanced robotic arm solution, joint-specific applications for the knee and hip, and orthopedic implants for orthopedic procedures in the United States and internationally. The consensus price target is $12.

ViroPharma Inc. (NASDAQ: VPHM) is expected to deliver growth despite a poor quarter. ViroPharma’s commercial and pipeline progress is on track, with new timelines announced for several clinical programs. With its lead drug Cinryze continuing to show growth and what appears to be growing market share, the company is moving beyond the loss of its Vancocin franchise. The consensus price target for the stock is $33.

Cubist Pharmaceutical Inc. (NASDAQ: CBST) is the ultimate binary event play. With a critical court decision pending, the stock could have tremendous movement, depending on the outcome. Cubists’ primary revenue drug Cubicin (daptomycin), which is an injectable antibiotic with nearly $1 billion in sales, is being challenged by a generic drug manufacturer. Investors need to be very careful here. The consensus price target for the stock is $52.50.

With a penchant for large-cap names with huge momentum and small-cap names on the verge of a big success, PropThink offers a good balance of biotech information and data. Again, investors should remember that some of the highly speculative stocks may be totally unsuitable for conservative portfolios. With that caveat in place, some of the names could also lead to spectacular gains.

In a close examination of their stocks to buy, Merrill Lynch analysts sought to (1) point out possible product launches and (2) highlight important milestones, including potential threats for the companies in their coverage universe. The firm also summarized quarterly growth and margin trends and provided a valuation snapshot for each company. Here are the stocks to buy from Merrill Lynch.

AbbVie Inc. (NYSE: ABBV) seems to be on the radar at most major Wall Street firms, despite the fact that 50% of all revenues are from one drug (Humira). Merrill Lynch is bullish on the stock given its attractive valuation, above-average dividend yield, and the potential for the pipeline to deliver a blockbuster hepatitis C (HCV) franchise over the medium term. Their price target for the stock is $49. The Thomson/First Call consensus target is $45.50. Investors are paid a 3.60% dividend.

Bristol-Myers Squibb Co. (NYSE: BMY) is a stock to buy. Merrill Lynch analysts do have some concern over the pipeline of future products. They believe that pipeline setbacks could pressure the stock, but a solid dividend yield should limit downside risk. The Merrill Lynch price objective for the stock is $45. The consensus target is much lower at $38. Investors receive a 3.50% dividend.

Eli Lilly & Co. (NYSE: LLY) is considered a “sum-of-the parts” stock to buy. Continued strong cash flow generation, a focus on shareholder return through a stable dividend, expense control and potential for positive pipeline news could improve sentiment over time and lead to multiple expansion. The Merrill Lynch price target is $65. The consensus is, again, much lower at $57. Shareholders are paid a 3.60% dividend.

Merck & Co. Inc. (NYSE: MRK) is a stock to buy with characteristics similar to the Eli Lilly story. Merrill Lynch analysts are looking for continued strong cash flow generation, focus on shareholder return through a stable dividend (with potential for growth) and share buybacks, and potential for positive pipeline news could improve sentiment over time and lead to multiple expansion. The Merrill Lynch price target for the stock is $53, while the consensus is at $51. Investors are paid a 3.80% dividend.

Pfizer Inc. (NYSE: PFE) rounds out the list of large cap stocks to buy. With a solid current revenue base and a growing pipeline, Pfizer may have the most potential of the stocks to buy. The Merrill Lynch price target is $33. The consensus is $32. Shareholder are paid a 3.30% dividend.

While the Merrill Lynch report did not assess macro issues, which can play an important role in driving stock performance, it was very helpful for company-specific analysis. Combining strong growth potential with consistent and possibly rising dividends, make large cap pharmaceutical stocks a good bet for any portfolio.

Through an arrangement with CVS Caremark Corp. (NYSE: CVS), patients who have a valid prescription for Viagra will be able to order the medication online. Other treatments for erectile dysfunction like Cialis from Eli Lilly & Co. (NYSE: LLY), Levitra and Staxyn from GlaxoSmithKline (NYSE: GSK) and Germany’s Bayer A.G., Stendra from Vivus Inc. (NASDAQ: VVUS) and Zydena from South Korea’s Dong-A are likely to be the first followers as patients with prescriptions for these drugs may want to avoid the stigma — real or imagined — attached to purchasing these drugs in person.

But the makers of other drugs will be watching as well. By selling direct, drug makers avoid two problems. First is counterfeiting. Viagra, which sells by prescription for $25 a tablet, is often faked by online sellers and sold as the real thing. That damages the drug’s brand and keeps profits out of Pfizer’s hands.

Second, Pfizer will not undersell its distribution chain, at least not yet, meaning that the company will put more profit in its pocket. For Viagra, with sales of $2 billion a year, the company may realize some additional profit, but by promoting Web sales as offering “real Viagra,” Pfizer is offering a guarantee that the knock-off sites cannot match.

Makers of weight-loss drugs will be watching Pfizer’s Web sales closely, and these may be the next drugs to hit the market directly from manufacturers to patients. Drugs like Viagra attract more Internet searches from men and weight-loss medications more searches from women than any other medications.

If Pfizer can pull this off, it could decide to extend Web sales for other drugs or it could promote sales from online pharmacies like CVS or Walgreen Co. (NYSE: WAG). Once again, the Internet changes everything.

Under Pfizer’s new system, men armed with a prescription can order their drugs, have the order filed at CVS Caremark Corp. (NYSE: CVS) and then mailed. Pfizer describes the benefits of the system this way:

CONVENIENCE AND PRIVACY of ordering from your home with FREE shipping in the continental U.S.

CONFIDENCE in knowing that your order is being handled by trusted pharmacists and that your information is secure.

SAVINGS AND OFFERS found on VIAGRA.com that can also be redeemed at your local pharmacy or preferred online pharmacy with a valid prescription for VIAGRA.

Cialis and Levitra can, and probably have to, match the initiative immediately. Through programs for the three, online erectile dysfunction products can follow a system pioneered by companies such as Amazon.com Inc. (NASDAQ: AMZN) in which consumers can buy everything from books to consumer electronics to clothing. Perhaps the three drugs should have joined these other products years ago. It could have blunted the rise of the black market and made the sales of them easier for the consumer, a benefit that other categories of products discovered years ago.

The marketers at Cialis maker Eli Lilly & Co. (NYSE: LLY) and Levitra maker GlaxoSmithKline PLC (NYSE: GSK) are too intelligent and aggressive to allow Pfizer’s plan go unchallenged for too long.

All the men who were embarrassed about their erectile problems can now sneak on to the Internet, get their pills delivered to their homes, and, by the way, get three free pills in the process.

Maybe the big pharmaceutical company figures it is easier to use a computer than to walk into a drug store. After all, contact lenses already are available on the Internet. Another theory is that men are embarrassed to let their local pharmacist know that they have an erection problem.

Whatever the reason, the Houston Chronicle reports on getting Viagra online:

Men still will need a prescription to buy the blue, diamond-shaped pill on viagra.com, but they no longer have to face a pharmacist to get it filled. And for those who are bothered by Viagra’s steep $25-a-pill price, Pfizer is offering three free pills with the first order and 30 percent off the second one.

Pfizer’s bold move blows up the drug industry’s distribution model. Drugmakers don’t sell medicines directly to patients. Instead, they sell in bulk to wholesalers, who then distribute the drugs to pharmacies, hospitals and doctors’ offices.

But the world’s second-largest drugmaker is trying a new strategy to tackle a problem that plagues the industry. Unscrupulous online pharmacies increasingly offer patients counterfeit versions of Viagra and other brand-name drugs for up to 95 percent off with no prescription needed. Patients don’t realize the drugs are fake or that legitimate pharmacies require a prescription.

Those fake drugs do not work, anyway.

Arena made its announcement last night when it reported first-quarter earnings. The company said it is “currently evaluating the best approach for submitting at a later date.”

Belviq is one of three new weight-loss drugs from different makers, and was the first new medicine of its kind to receive U.S. Food and Drug Administration (FDA) approval in 13 years. Qsymia, from Vivus Inc. (NASDAQ: VVUS) and Contrave from Orexigen Therapeutics Inc. (NASDAQ: OREX) are the others. Qsymia has also received FDA approval while Orexigen is expected to reapply for Contrave approval later this year or early next.

Arena is likely to have withdrawn its application in order to avoid being rejected by the European regulators. None of the three competing weight-loss drugs has been approved for use in Europe.

Shares of Arena are getting hammered in premarket trading this morning, down about 14.4% to $7.19, in a 52-week range of $2.32 to $13.50.

Shares of Vivus are up 2.7%, at $13.30 in a 52-week range of $9.86 to $31.21.

On a GAAP basis, AbbVie reported quarterly EPS of $0.60, which excludes intangible asset amortization expenses and other items.

The company affirmed its adjusted EPS guidance for the full year of $3.03 to $3.13, which does not include $0.37 per share of items primarily related to costs associated with its separation from Abbott Labs.

The company’s CEO said:

The business generated strong sales growth despite loss of exclusivity in our lipid franchise, which speaks to the foundation of AbbVie’s product portfolio. Additionally, we advanced our promising pipeline during the first quarter, with continued progress across our mid- and late-stage development programs.

AbbVie has now put a stake in the ground and provided investors with some information about the company going forward. Adjusted gross margin totaled 76.2% in the first quarter, and operating profit of $1.31 billion topped the $978 million the company earned in the first quarter of 2012.

The company’s shares are down about 0.1% in premarket trading, at $44.20 in a post-IPO range of $32.51 to $46.32. Thomson Reuters had a consensus analyst price target of around $40.90 before today’s report.

On a GAAP basis, Abbott posted EPS of $0.34.

On the revenue side, Abbott said that excluding the effects of currency exchange rates, the company’s revenues rose by 3.5%. Including exchange rate effects, revenues rose by just 1.8%. U.S. sales fell by 3.3% and sales in the medical devices group fell by 12.7%. Sales gains in the nutrition and diagnostics segments totaled 2.1% and 2.9%, respectively.

The company’s CEO said:

Strong performance in Nutrition and Diagnostics, as well as overall results in emerging markets, led our sales growth this quarter. We had significant new product and geographic expansion activity during the quarter that positions Abbott well for continued growth.

Abbott confirmed its full-year adjusted EPS guidance of $1.98 to $2.04, in line with the consensus estimate of $2.01. GAAP EPS is expected to total $1.39 to $1.45 due to items including intangible amortization expenses and cost reduction expenses. For the second quarter, Abbott expects to post adjusted EPS of $0.43 to $0.45, which does not include $0.16 in one-time items.

Shares of Abbott are trading down in the premarket this morning, at $35.80 in a 52-week range of $31.64 to $72.47. Thomson Reuters had a consensus analyst price target of around $37.90 before today’s report.

In the past three years, some 40 China-based firms have announced deals to take the company private and nearly half the deals have been backed by private equity firms. One of the largest is the $3.7 billion deal to take private China’s premier display advertising firm, Focus Media Holding Ltd. (NASDAQ: FMCN). The Carlyle Group L.P. (NASDAQ: CG) is joining with the company’s CEO in the buyout.

Other recent take-private deals include one for Zhongpin Inc. (NASDAQ: HOGS) and another for fertilizer maker Yongye International Inc. (NASDAQ: YONG). Zhongpin’s chairman is taking the company private on his own, and Yongye’s CEO is getting help from a branch of Morgan Stanley (NYSE: MS). Carlyle Group is also involved in going-private deal worth $688 million for 7 Days Group Holdings Ltd. (NYSE: SNN). Chinese pharmaceutical maker Simcere Pharmaceutical Group (NYSE: SCR) also got an offer from its chairman to take the drug maker private.

One question follows from all this activity: what about China’s struggling solar makers? Now that Suntech Power Holdings Co. Ltd. (NYSE: STP) is no longer a factor, it is interesting to speculate on the possibility of a take-private deal for one of the other solar players. Names that spring immediately to mind are LDK Solar Co. Ltd. (NYSE: LDK), Trina Solar Ltd. (NYSE: TSL), Canadian Solar Inc. (NASDAQ: CSIQ) and ReneSola Ltd. (NYSE: SOL).

LDK has issued 12 million newly minted shares to Fulai Investments, giving the firm about 11% of the company. A state-controlled firm owns another 20% of LDK. With a current total market cap of just $141 million, LDK would seem ripe for a take-private deal, especially after shedding one of its largest plants to a provincial government. A government-engineered takeover is more likely here due to the government’s heavy involvement with LDK already.

Trina is one of the companies expected to get some benefit from the downfall of Suntech. The company says it will meet $83.5 million loan payment due July 15. There has been no indication that Trina is being targeted for a take-private deal, but with a market cap of around $260 million the opportunity is there.

Canadian Solar, with a market cap of just $150 million, could be another take-private candidate. The company has a solar installation business, and that promises to help make up for the low prices for wafers and modules. Earlier this year the company got a $40 million loan from Credit Suisse to acquire four projects in Ontario.

ReneSola just received a $51 million loan from a Chinese government-controlled bank, and with a market cap below $125 million, this one is the cheapest of the bunch. But again, the government stake in ReneSola is a negative to taking the company private.

Perhaps the biggest issue with taking a solar company — or any other for that matter — private is how good the chances are that the company can be floated to the public again. No private equity fund is going to bail in to a deal without a clear plan for bailing out. There are not likely to be a lot more buyers for solar makers in another two or three years.

For founders and company executives, taking a Chinese firm private could be a matter of pride. Because these are the very guys who drove the companies to the brink of extinction in the first place, partnering with them seems needlessly risky. Suggestions that firms might consolidate also are unlikely to get much traction in China, again mainly as a matter of pride.

As with so many things in China, the government likely will be responsible for picking winners and losers in the solar business. The government surely could have rescued Suntech, but chose not to. On that basis, the loan to ReneSola is encouraging for that firm.

From here, though, LDK continues to look like the next target, and it will not be a buyout but a government takeover in some form. Trying a merger arbitrage play here, just in case a buyer should pop up, could be a safe bet with some possible upside if the government eventually does ride to the rescue.

In last night’s announcement, Affymax said it was taking these steps “to focus the company’s resources on the ongoing investigation of reported hypersensitivity reactions” to its leading drug. The company was forced to recall its anemia drug, Omontys, in February after 50 patients developed severe allergic reactions to the injectable drug and five people died. Affymax really has no other drug pipeline available to take up the slack from the recall, which may turn out to be permanent. Japan’s Takeda Pharmaceutical Co. is a partner with Affymax in making and distributing Omontys.

Among the strategic alternatives the company is considering are further restructuring, a “wind-down of operations, or even bankruptcy proceedings.”

Shares of Affymax are down more than 56% in premarket trading this morning, at $1.27, well below the 52-week range of $2.26 to $27.74.