This Day On The Street
Continue to site right-arrow
This account is pending registration confirmation. Please click on the link within the confirmation email previously sent you to complete registration.
Need a new registration confirmation email? Click here
Stocks Under $10 with 50-100% upside potential - 14 days FREE!

Biotech Stock Mailbag: PTC Therapeutics, Vanda, MannKind

Stocks in this article: PTCT SRPT VRTX VNDA MNKD

BOSTON ( TheStreet) -- An email from D.H. kicks off this week's Biotech Stock Mailbag.

Do you have any thoughts on PTC Therapeutics (PTCT)? They are in the process of going public. It is an interesting example of post-hoc subgroup analyses. Would be interested in seeing an article on this.

PTC Therapeutics went public Wednesday night, selling 8.4 million shares at $15 and raising about $114 million. That's a decent haul for a company developing a drug with a spotty clinical and regulatory track record. The stock closed Thursday, it's first trading day, up 10% to $16.49.

Existing PTC investors bought a bit less than 40% of the shares sold during Wednesday night's public offer, which takes some of the shine off the first-day trading performance.

PTC's lead drug ataluren is designed to treat patients with genetic disorders arising from so-called "nonsense mutations" which cause cells to produce shortened and malfunctioning proteins. Ataluren is supposed to act like a detour around the nonsense mutation, allowing cells to produce full-length, functional proteins.

Ataluren's mechanism of action is similar to the drugs being developed by Sarepta Therapeutics (SRPT) and Vertex Pharmaceuticals (VRTX) for Duchenne muscular dystrophy and cystic fibrosis, respectively. In fact, PTC is targeting DMD and CF as lead indications for ataluren, although for subgroups of patients with different mutations so not directly competitive to either company.

Sounds promising, except ataluren has a bad habit of failing clinical trials. A phase IIb study conducted a few years ago in DMD patients with nonsense mutations failed to show a significant walk benefit. Likewise, a phase III study of ataluren in cystic fibrosis patients failed to demonstrate a benefit in lung function.

Despite the clinical setbacks, PTC is pushing ahead with ataluren's development based on promising hints of efficacy observed in subgroups of patients enrolled in the previous studies. These are the "post-hoc subgroup analyses" that D.H. refers to in his email.

There's some validity to PTC's approach, particularly in DMD where we know now that younger kids and those with higher baseline walking ability tend to have disease that progresses more slowly i.e. the loss of muscle function and walking ability of these "less sick" kids doesn't decline as rapidly. This makes it harder for any DMD drug to demonstrate a benefit.

PTC's phase IIb study enrolled a good number of these "less sick" DMD kids in addition to older kids with more advanced disease. Excluding the former and including only the latter in a post-hoc efficacy analysis showed a more profound ataluren benefit.

1 of 4

Select the service that is right for you!

Action Alerts PLUS
Try it NOW

Jim Cramer and Stephanie Link actively manage a real portfolio and reveal their money management tactics while giving advanced notice before every trade.

Product Features:
  • $2.5+ million portfolio
  • Large-cap and dividend focus
  • Intraday trade alerts from Cramer
  • Weekly roundups
TheStreet Quant Ratings
Try it NOW
Only $49.95/yr

Access the tool that DOMINATES the Russell 2000 and the S&P 500.

Product Features:
  • Buy, hold, or sell recommendations for over 4,300 stocks
  • Unlimited research reports on your favorite stocks
  • A custom stock screener
  • Upgrade/downgrade alerts
Stocks Under $10
Try it NOW

David Peltier, uncovers low dollar stocks with extraordinary upside potential that are flying under Wall Street's radar.

Product Features:
  • Model portfolio
  • Stocks trading below $10
  • Intraday trade alerts
  • Weekly roundups
Dividend Stock Advisor
Try it NOW

Jim Cramer's protege, David Peltier, identifies the best of breed dividend stocks that will pay a reliable AND significant income stream.

Product Features:
  • Diversified model portfolio of dividend stocks
  • Alerts when market news affect the portfolio
  • Bi-weekly updates with exact steps to take - BUY, HOLD, SELL
Real Money Pro
Try it NOW

All of Real Money, plus 15 more of Wall Street's sharpest minds delivering actionable trading ideas, a comprehensive look at the market, and fundamental and technical analysis.

Product Features:
  • Real Money + Doug Kass Plus 15 more Wall Street Pros
  • Intraday commentary & news
  • Ultra-actionable trading ideas
Options Profits
Try it NOW

Our options trading pros provide daily market commentary and over 100 monthly option trading ideas and strategies to help you become a well-seasoned trader.

Product Features:
  • 100+ monthly options trading ideas
  • Actionable options commentary & news
  • Real-time trading community
  • Options TV
To begin commenting right away, you can log in below using your Disqus, Facebook, Twitter, OpenID or Yahoo login credentials. Alternatively, you can post a comment as a "guest" just by entering an email address. Your use of the commenting tool is subject to multiple terms of service/use and privacy policies - see here for more details.
Submit an article to us!


DOW 17,804.80 +26.65 0.15%
S&P 500 2,070.65 +9.42 0.46%
NASDAQ 4,765.38 +16.9840 0.36%

Brokerage Partners

Rates from

  • Mortgage
  • Credit Cards
  • Auto

Free Newsletters from TheStreet

My Subscriptions:

After the Bell

Before the Bell

Booyah! Newsletter

Midday Bell

TheStreet Top 10 Stories

Winners & Losers

Register for Newsletters
Top Rated Stocks Top Rated Funds Top Rated ETFs