Investor interest in biotech is enjoying a prosperous comeback, leading industry watchers and journalists to seek reasons for the frenzy. In The New York Times' DealBook post, one of the recurring themes among the high-flying drug developers, was a focus on personalized medicine.

"Personalized medicine" is one of the most overused terms in the life sciences world, yet many of the hottest biotech companies, including those involved in major deals such as IPOs and big-money overtures from pharma giants, are developing molecularly targeted drugs against diseases for which there are inadequate or no treatment options.

Take Epizyme ($EPZM). The Cambridge, MA-based biotech firm busted out a successful IPO in May based in part on the promise of an epigenetic enzyme inhibitor called EPZ-5676 that could be the first targeted drug for a deadly blood, cancer mixed lineage leukemia. The drug only entered early-stage clinical trials last fall, but positive signs of efficacy could put the compound on a speedy path to an approval because of the FDA's eagerness to streamline development of new therapies for patients in need.

"The regulators, notably the FDA, have been particularly willing to come up with new strategies to enable the rapid development of drugs for which there is a dramatic effect in a defined patient population," Third Rock Ventures partner Robert Tepper told the NYT blog. "If you can stratify the patient population you want to treat through genetic analysis, for example, you can move quite quickly through early-stage trials."

Third Rock and other believers in personalized medicine are capitalizing on the heated interest in the next wave of biotech companies. Bluebird Bio ($BLUE), a Third Rock-backed biotech group, soared out of the IPO gate last month as investors flocked to own a piece of the gene therapy company. Investors have rewarded the company for focusing on life-changing genetic therapies for rare diseases.

More than 20 life sciences outfits have pulled off IPOs in 2013, ending a dry spell for public debuts in biotech that began after the 2008 market crash. As DealBook noted, bluebird, Epizyme and DMD drug researcher Prosensa ($RNA) are among the hottest publicly traded biotech companies on the year.

"Many companies that have done well recently have a specific molecular-medicine approach to a serious disorder that has no other therapies," said Christoph Westphal, a founder of the biotech backer Longwood Fund, as quoted by the NYT blog.