Every biotech company goes into a clinical study with great hopes -- and often great fears, as well. There's no guarantee that all will go well. All the time and money poured into an experimental drug can go down the drain with bad results. But good results mean an entirely different story.

Three biotechs especially felt the thrill of good clinical results over the past week: Insmed (NASDAQ:INSM), Newlink Genetics (NASDAQ:NLNK), and Voyager Therapeutics (NASDAQ:VYGR). All three stocks skyrocketed, with two of them pretty much going into orbit. Here's why Insmed, Newlink Genetics, and Voyager had such great weeks -- and what their chances could be for keeping the momentum going. 

Hand with pen pointing to red line going up

Image source: Getty Images.

Insmed

Insmed stock zoomed nearly 150% this week after the biotech announced great results from a late-stage clinical study. Twenty-nine percent of patients with nontuberculous mycobacterial (NTM) lung disease caused by Mycobacterium avium complex (MAC) taking the company's drug, Amikacin Liposome Inhalation Suspension (ALIS), in addition to guideline-based therapy, showed no evidence of NTM lung disease in the sixth month of treatment. That was significantly higher than the 9% of patients with similar improvement who took guideline-based therapy alone.

What does all that mean? NTM is a rare disease, but its prevalence is growing. There are some drugs used to treat the disease, including an intravenous version of amikacin. However, there are some serious side effects for these drugs, and they're often not effective. The best therapy for NTM isn't even approved for treating the disease. 

Insmed's phase 3 results should bode well for the biotech's chances of winning regulatory approval for ALIS. The company plans to pursue accelerated approval of the drug. 

Newlink Genetics

Newlink Genetics stock vaulted more than 125% this week. The biotech released updated data from a phase 2 clinical study evaluating the use of IDO-inhibitor indoximod, alongside Merck's Keytruda, in treating advanced melanoma patients.

Two findings from that phase 2 study particularly pleased investors. Newlink said that progression-free survival (PFS) was 56% after a year of treatment with the indoximod/Keytruda combo, with median PFS of 12.9 months. Also, complete response improved from the 12% announced previously to 20%. 

This better news helped bolster Newlink Genetics' decision to move forward with a pivotal late-stage study of indoximod with Keytruda and Bristol-Myers Squibb's Opdivo in treating advanced melanoma. The company hopes to enroll patients in the study by the end of 2018. 

Voyager Therapeutics

Voyager Therapeutics stock's jump of more than 45% seems relatively small in comparison to the huge gains for Insmed and Newlink Genetics. However, its shareholders are certainly excited by the company's positive results from an early-stage study of gene therapy VY-AADC01 in treating advanced Parkinson's disease.

Parkinson's disease patients who received a one-time administration of VY-AADC01 experienced improved motor function after six months and 12 months. Higher doses of the therapy resulted in greater improvement. Patients experienced motor function improvement even with lower doses of their other medications, including leading Parkinson's disease drug levadopa. 

Voyager plans to begin a pivotal phase 2/3 clinical study of VY-AADC01 later this year. The first patient is expected to be dosed in the first half of 2018. 

Soaring higher?

Assessing the risks for each of these biotechs is as easy as one, two, three. Voyager Therapeutics' results were from a phase 1 study that included only 15 patients. The company's results are encouraging, but it's still very early. Newlink Genetics' risk level isn't quite as high because their good news came from a phase 2 study. Insmed faces the least risk with solid results from a phase 3 study.

However, all three of these biotech stocks could go higher despite different levels of risk. Insmed should get a nice bump if the FDA grants accelerated approval for ALIS. I suspect the odds of that happening are very good. Newlink Genetics' next catalyst that could boost the stock is probably the announcement of updated data from a phase 2 study of indoximod plus gemcitabine/nab-paclitaxel in treating pancreatic cancer. That should occur either later this year or in early 2018. 

While Voyager Therapeutics has the greatest risk, I think the stock could also have the most room to go higher over the long run. Voyager has the smallest market cap of the three and potentially the most promising pipeline candidate. There's still a long way to go, though. 

Keith Speights has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.