This Week in Biotech

With the SPDR S&P Biotech Index up 35% over the trailing-12-month period, it's evident that investment dollars are willingly flowing into the biotech sector. Keeping that in mind, let's have a look at some of the rulings, studies, and companies that made waves in the sector last week.

There weren't many well-known names making big moves this week, but we were privy to a good variety of stories including FDA designations and new drug filings, plenty of analyst action, and a late-week, rally-killing share offering.

The best-known, and potentially most exciting, story of the week was the Food and Drug Administration's classification of Pfizer's (NYSE: PFE  ) Palbociclib as a "breakthrough therapy." Palbociclib is an oral treatment for ER+, HER2-positive metastatic breast cancer that, in trials, when combined with Novartis' Femara, crushed the control arm made up of Femara alone in terms of progression-free survival (26.1 months versus 7.5 months). Those amazing results earned Palbociclib this extremely rare designation from the FDA, which should help expedite its development and hopeful approval of the drug. 

ACADIA Pharmaceuticals (NASDAQ: ACAD  ) added on 63% since last Friday, following an announcement that the FDA will allow it to file an accelerated new drug application for its Parkinson's disease anti-psychosis drug, Pimavanserin. ACADIA's drug met the primary endpoint of demonstrating highly significant anti-psychotic activity and the secondary endpoint of increased motoric tolerability in its late-stage trial, which provided more than enough evidence for the FDA to give the company the go-ahead to skip another confirmatory trial. Pimavanserin's chances for approval definitely got a boost, but ACADIA's valuation certainly is giving me cause for concern.

The red-hot Astex Pharmaceuticals (NASDAQ: ASTX  ) continued its impressive surge after updating its preclinical progress on SGI-110 on Wednesday. Astex noted that "in ovarian cancer xenograft models, SGI-110 in combination with platinum significantly delayed tumor growth." In addition, the combination was shown to induce demethylation and increased expression of multiple tumor suppressor and tumor differentiation genes. The good news here is this data would support the ongoing midstage trials for which SGI-110 is currently being used in combination with Carboplatin to treat platinum-resistant ovarian cancers. Shares of Astex are now up 119% year to date.

AcelRx Pharmaceuticals (NASDAQ: ACRX  ) received a nice boost from Jefferies this week, after an analyst there initiated coverage on the company with a "buy" rating and a price target of $8, implying about 33% upside from Friday's close. The covering analyst, Corey Davis, is forecasting that AcelRx's post-operative pain management drug/system, sufentanil NanoTab PCA -- which allows patients to give themselves a pre-set dose of sufentanil under their tongue instead of intravenously -- will be approved by the FDA in 2014 and become up to a $400 million drug in the United States. AcelRx's delivery system does drastically reduce the potential for infections and dosing errors, but I always remain concerned when pain medication systems go before the FDA. In essence, I'd still tread cautiously around this story.

Finally, Synergy Pharmaceuticals (NASDAQ: SGYP  ) may have had the wildest week of them all. Synergy's share price spiked 16% on Tuesday as an analyst at Cantor Fitzgerald raised her peak sales estimate for plecandtide, the company's midstage drug for chronic idiopathic constipation and irritable bowel syndrome with constipation, to $1.58 billion from $1.05 billion, as clinical data has been stronger than expected. However, the company didn't return the favor to shareholders by -- the very next day, mind you – announcing a secondary offering of 16.375 million shares. The downside of clinical-stage companies is the always apparent risk of dilution. Shares have lost 25% since their Tuesday close.

While you can certainly make huge gains in biotech and pharmaceuticals, the best investing approach is to choose great companies and stick with them for the long term. The Motley Fool's free report "3 Stocks That Will Help You Retire Rich" names stocks that could help you build long-term wealth and retire well, along with some winning wealth-building strategies that every investor should be aware of. Click here now to keep reading.