Is This Good Drug Good Enough?

Threshold Pharmaceuticals' (Nasdaq: THLD  ) TH-302 is a good drug. It just isn't a super-duper extraordinary drug.

Apparently investors were looking for the latter and sent shares down 20% on Monday.

We already knew the drug delayed the progression of pancreatic cancer. Back in Febuary, Threshold said TH-302 combined with Eli Lilly's (NYSE: LLY  ) Gemzar produced a 63% improvement in progression-free survival compared with Gemzar alone.

This week, Threshold presented the full data package, including overall survival. Patients taking the higher dose of TH-302 combined with Gemzar lived 9.2 months compared to 6.9 months for Gemzar alone. While numerically longer, the results weren't statistically significant.

But they weren't designed to be. This was a phase 2 clinical trial with just 214 patients split into three different treatment groups. While overall survival was measured, it was only a secondary endpoint of the study, in part because patients that progressed on Gemzar alone were allowed to crossover and take TH-302. That may have increased the survival of the Gemzar-alone group.

With enough patients in the phase 3 trial, Threshold and partner Merck KGaA should be able to show statistical significance for the 2.3 month increase in survival.

The question, of course, is how much confidence we should have that the difference between the two treatment groups will remain that wide. The phase 2 data could have just happened by chance; that's the definition of not being statistically significant.

There are some hints that the difference might be real, though. The increase in progression-free survival is a good one. If TH-302 is delaying the growth of the tumor, there's a good chance that translates into an increase in survival, although it's no guarantee. For some types of tumors, Roche's Avastin showed increases in PFS but not overall survival. Ditto for Amgen's (Nasdaq: AMGN  ) Vectibix, Eli Lilly's Alimta, and Celgene's (Nasdaq: CELG  ) Thalomid as a maintenance therapy. Of course, there are more examples where the two correlated well than where they failed.

Another nugget of potentially good news is that a second lower dose tested in the phase 2 trial produced survival that was between the placebo and the higher dose. A dose response is a good sign that an effect is real.

Ultimately, it'll be the phase 3 trial that determines if TH-302 is good enough to get approved. It would've been nice if the drug produced survival data so wonderful that the phase 3 trial was an easy layup, but not all drugs can be of the super-duper variety.

If you want super-duper stocks, these three have an X factor that makes them stand out from their illustrious Dow peers. Find out what it is in the Fool's new free report, "The 3 Dow Stocks Dividend Investors Need."

Fool contributor Brian Orelli holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool has a disclosure policy.
We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.


Read/Post Comments (3) | Recommend This Article (1)

Comments from our Foolish Readers

Help us keep this a respectfully Foolish area! This is a place for our readers to discuss, debate, and learn more about the Foolish investing topic you read about above. Help us keep it clean and safe. If you believe a comment is abusive or otherwise violates our Fool's Rules, please report it via the Report this Comment Report this Comment icon found on every comment.

  • Report this Comment On September 18, 2012, at 4:13 PM, caution1st wrote:

    Decent summary of yesterday's events and the company with the exception that the pancreatic trials are one of 11 trials the company has in progress. The most advanced of which is a phase 3 Sarcoma trial on which Threshold is expected to file an NDA in late 2014.

    To relate the value of the company to one trial when there are so many others in the pipeline does not tell your readers the whole story.

    You did however, point out the critical points of the pancreatic news release and highlighted why the numbers were what they were.

    Overall, Good job.

  • Report this Comment On September 18, 2012, at 4:19 PM, TruffelPig wrote:

    I basically wrote something similar in my reply to this yesterday: http://www.fool.com/investing/general/2012/09/17/why-thresho...

    I loaded up on shares! Today justified my buy completly.

  • Report this Comment On September 18, 2012, at 8:47 PM, Hope4GoodFuture wrote:

    I like the way you write Dr. Orelli. You are one of the few biotech writers that I bother to read.

    I'm a layperson, but one thing nags me about the TH-302 trial. Following CLVS' CO-101, I've learned about (their theory of) the importance of hENT high/low status with Gemzar. They say that a meaningful % of pancreatic cancer patients are hENT low and Gemzar will have no impact on them. I guess that means that a meanful % of the TH-302/Gemzar trial patients are hENT low. I suppose this means that if patients are hENT low, the only drug they are getting benefit from in the combo is TH-302, and if they are hENT high, they get benefit from both. Since I don't believe THLD is using hENT status to select the different arms, couldn't this mean that there is a lot of variability in hENT status between the arms that could significantly impact the relative results? That seems like a big risk. It seems that a phase III design might want to contemplate hENT status. It seems that if CLVS's drug works, TH-302 will be paired with either Gemzar or CO-101 depending on hENT status. It would be interesting to know what, if any, biomarkers influence the efficacy of Abraxane in pancreatic cancer- if there are no major ones like hENT, that might make Abraxane appear to be more effective, not because it actually is, but because of TH-302 trial failing to contemplate this. Any thoughts?

Add your comment.

Sponsored Links

Leaked: Apple's Next Smart Device
(Warning, it may shock you)
The secret is out... experts are predicting 458 million of these types of devices will be sold per year. 1 hyper-growth company stands to rake in maximum profit - and it's NOT Apple. Show me Apple's new smart gizmo!

DocumentId: 2021632, ~/Articles/ArticleHandler.aspx, 10/24/2014 5:51:29 AM

Report This Comment

Use this area to report a comment that you believe is in violation of the community guidelines. Our team will review the entry and take any appropriate action.

Sending report...


Advertisement