With the SPDR S&P Biotech Index up 38% 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.

Clinically mixed reviews
Unlike the previous two weeks where we've been privy to almost nothing but positive clinical data, this week proved somewhat challenging.

One clinical trial that clearly had no issues was the release by AbbVie (ABBV 0.25%) of its second of six late-stage results for its direct-acting antiviral combo drug to treat hepatitis-C. In this trial, dubbed Sapphire-II, its DAA-combo delivered a sustained virologic response after 12 weeks of 96% in genotype 1 patients, with just 1% of total patients dropping out because of adverse events. In English, this just means that all detectable levels of hepatitis-C were eradicated in 96% of patients with the most common type of hepatitis-C in just 12 weeks. Best of all, the DAA-combo works without the need for interferon which can cause nasty flu-like side effects in patients. Enanta Pharmaceuticals (NASDAQ: ENTA) which makes ABT-450, one of the three combo components, also soared on the news.

The picture, though, was quite mixed for Infinity Pharmaceuticals (INFI) following the release of positive early-stage data for its PI3K inhibitor IPI-145 at the annual American Society of Hematology, or ASH, meeting. In phase 1 studies, IPI-145 demonstrated an overall response rate, or ORR, of 73% as a monotherapy treatment for indolent non-Hodgkin's lymphoma while also showing a 20% complete response in patients. Within its phase 1 chronic lymphocytic leukemia trial, it delivered an ORR of 48%, with nodal responses noted in 89% of CLL patients. Furthermore, Infinity also noted that IPI-145 demonstrated clinical benefit activity in the preclinical setting for treating diffuse large B-cell lymphoma and T-cell acute lymphoblastic leukemia. Despite what appears to be positive news on the surface, investors pushed shares of Infinity lower on the week by 13%.

On the other end of the spectrum we have clinical-stage small-cap biopharmaceutical company Curis (CRIS -4.58%), which was undeniably stomped on after reporting preliminary data for its ongoing phase 1 study of dual PI3K/HDAC inhibitor CUDC-907 for relapsed/refractory lymphoma or multiple myeloma at ASH. Curis' ongoing study showed that one patient had demonstrated a partial anti-tumor response, while seven of 11 evaluable patients were exhibiting signs of stable disease. Concerning investors, however, was that the daily dose was associated with a high number of adverse events as well as the fact that only one patient demonstrated an anti-tumor response. CUDC-907 is expected to be the cornerstone of Curis' future and investors are clearly not as sold on its anti-cancer effect at the moment. Consider, though, that dose escalation is still ongoing in the bi-weekly trial arm, so don't kill off the prospect of CUDC-907 succeeding just yet. 

The A-OK from the FDA ... panel, that is!
The second time proved the charm for AstraZeneca (AZN -0.25%) and Bristol-Myers Squibb's (NYSE: BMY) SGLT2 inhibitor, dapagliflozin (known as Forxiga in the EU), which on Thursday received a recommendation for approval from the FDA's advisory panel. The panel voted 13-1 that the benefits of the drug outweighed its risks, and 10-4 in favor of its cardiovascular risk profile. Dapagliflozin was actually rejected in 2011 because of concerns about an elevated risk of bladder or breast cancer from the pill, so this thumbs-up from the FDA's panel could go a long way to pushing this revolutionary new drug over the approval hump. Although the FDA isn't required to follow the recommendation of its panel, I would personally be surprised to see it not approve dapagliflozin.

Season's greetings, from your Inspector General
Finally, Insys Therapeutics (INSY) ended the week on a sour note after announcing that it had received a subpoena from the Inspector General of the Department of Health and Human Services with regard to its marketing and sales practices for Subsys, a sublingual spray used to treat severe pain in cancer patients. Keep in mind that investigations into marketing practices sometimes lead to no findings of wrongdoing or a simple slap on the wrist. In other cases, though, they've led to multibillion-dollar fines. Since Subsys comprised 97% of Insys' revenue as of the third-quarter, shareholders are clearly on edge.