One more note, particularly for traders: Keep in mind that Merrimack is conducting multiple phase 2 studies of another cancer drug, MM-121 with data read-outs expected in the fourth quarter, likely before we hear about the MM-398 study results.

Moving on to Prosensa ( RNA) and the highly anticipated release of study results on its Duchenne muscular dystrophy drug drisapersen.

Despite my best effort, which included begging, Schikan was not willing to narrow down the window for when partner GlaxoSmithKline ( GSK) would be presenting the results from the drisapersen phase III study and the U.S.-based phase II "DEMAND-5" study. All he would say is drisapersen data will be presented at an upcoming medical meeting before the end of the year.

The possible venues and dates for the drisapersen data are:

World Muscle Society: Oct. 1-5
American Society of Human Genetics: Oct. 22-26
EURO-TIDES: Nov. 13-14
Oligonucleotide & Peptide Based Therapeutics Congress: Nov. 18-19

Based on positive efficacy seen in the previous "DEMAND-2" study presented in April, investors generally expect drisapersen to demonstrate a statistically significant benefit in six-minute walk distance in the phase III study as well.

The big risk to the outcome of the phase III study, as outlined by Schikan during our meeting Wednesday, is the effect that younger DMD boys (between 5 and 7) and those with greater walking ability at baseline will have on the overall results.

What we know now, but what Glaxo and Prosena say they didn't know when the phase III study was started, is that DMD kids younger than 7 are generally still capable of improvements in six-minute walk distance without treatment. It's not until DMD boys reach 7 that the disease begins to deteriorate muscle function to the point where walking becomes more difficult.

The worry is younger and healthier DMD patients enrolled in the phase III study may mute the overall treatment effect of drisapersen, thereby making it harder for the drug to demonstrate a statistically significant difference over placebo, Schikan said.

To be clear, Schikan wasn't warning me that the drisapersen phase III study was going to fail. Not at all. But he did speak rather openly about the risk of enrolling younger patients into the phase III study. Also, the phase III study does not stratify patients by age at enrollment, meaning there is a chance of an age imbalance between the drisapersen- and placebo-treated patients.

If you liked this article you might like

Verastem Shares Are Exploding 50% -- Here's Why

Otonomy Shares Rebound After Wednesday's Drop- Biotech Movers

Biotech Movers: Array Shares Rise on Bristol-Myers Collaboration

Trevena, Synergy Lead Biotech Movers

These 5 Stocks Under $10 Could Explode Up Soon