Who says the fireworks have to end on July 4th? There were still plenty of fireworks this week in the biotech industry.

Three biotech stocks turned in especially great performances over the last few days. The share prices of Benitec Biopharma (NASDAQ:BNTC), Zogenix (NASDAQ:ZGNX), and Arbutus Biopharma (NASDAQ:ABUS) soared 27% or more this week. What caused these biotech stocks to explode -- and are they buys now? 

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1. Benitec Biopharma: Let's make a deal

Shares of Benitec Biopharma skyrocketed 40% this week. The huge move came after Benitec announced on Monday that it was licensing exclusive global rights for gene therapy BB-301 to Axovant Sciences (NASDAQ:AXGT)

BB-301, which will now be known by the catchy name AXO-AAV-OPMD, uses a "silence-and-replace" approach to treat oculopharyngeal muscular dystrophy (OPMD). The PABPN1 gene mutation that causes OPMD is "silenced" by DNA-directed RNA interference. At the same time, the mutant version of the gene is replaced by a healthy version. 

Under the terms of the deal, Axovant will pay Benitec $10 million upfront with payments of $17.5 million contingent upon achieving near-term milestones. Benitec could also receive other development, regulatory, and commercial milestones in the future, bringing the total potential payments to $187.5 million. In addition, the small biotech stands to receive 30% of net profits on global sales of the OPMD gene therapy if it wins approval down the road.

2. Zogenix: A Dravet hooray

Zogenix stock jumped nearly 32% this week. The catalyst for the stock was the company's update on Thursday of phase 3 clinical results for lead candidate ZX008 in treating Dravet syndrome, a rare form of childhood-onset epilepsy.

Those results were pretty impressive. Patients taking ZX008 experienced a 54.7% reduction in mean monthly convulsive seizures compared to patients on placebo. Zogenix's drug also appeared to reduce seizure frequency by a statistically significant level versus placebo. The good news was completely unexpected, though: Zogenix reported positive results from an earlier phase 3 study of ZX008 in treating Dravet syndrome last year.

Based on the encouraging data from both late-stage studies of ZX008, Zogenix plans to submit the drug for approval in the U.S. and in Europe in the fourth quarter of 2018. The company is also evaluating ZX008 in a phase 3 study as a treatment for Lennox-Gastaut syndrome (LGS), another severe form of epilepsy.

3. Arbutus Biopharma: The pipeline is percolating

Arbutus Biopharma wasn't too far behind Zogenix, with its share price rising 27% this week. On Tuesday, Arbutus presented an update on progress with its pipeline that made investors happy campers.

The biotech announced that the first patient has been dosed in a phase 1 study evaluating AB-506 in treating patients infected by the hepatitis B virus (HBV). Top-line results from this study should be available by Q2 of 2019. Arbutus also said that it expects to begin dosing in another study of AB-452 in the fourth quarter of this year. These studies should set up the biotech to initiate an all-oral combination study of both experimental HBV drugs in the second half of 2019.

Arbutus could soon have more money flowing in the doors. The Food and Drug Administration is expected to announce its decision on approval for Alnylam's patisiran by Aug. 11, 2018. Arbutus stands to receive royalties if patisiran wins approval.  

Are they buys?

Let's take this week's biotech winners in alphabetical order. In my view, Arbutus has plenty of potential. However, I'd prefer to wait and see how its pipeline candidates actually perform. 

I think that it's way too early for most investors to buy shares of Benitec Biopharma. The Australian biotech's gene therapy probably won't even advance into clinical testing until next year.  

What about Zogenix? The positive results for ZX008 set up the biotech to likely go head-to-head against GW Pharmaceuticals, which won FDA approval a few weeks ago for cannabidiol (CBD) product Epidiolex in treating Dravet syndrome and LGS. GW will have a nice head start, though, in the Dravet syndrome market and an even greater one in LGS. This assumes, of course, that Zogenix wins approval for ZX008 in both indications.

My take is that the odds of approval for ZX008 in treating Dravet syndrome look really good based on the phase 3 data. It's hard to say how the drug will fare in treating LGS, but my guess is that Zogenix could gain another victory in the indication down the road. 

However, I don't think Zogenix is a great stock to buy right now. There are still several hurdles to jump. This week's big gain was warranted, but I'm not sure how much higher Zogenix will go.