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
TheStreet Open House

Why This Fund Manager Is Short Ziopharm

Again, take a look at the slide representing PFS data from the phase II study. The red curve is the patients treated with the palifosfamide combination. The blue circles above the red line represent "censored" patients. These are patients who are excluded from the PFS analysis because they were either lost to follow up or had not completed enough treatment cycles to be included in the analysis. It's a bit hard to count, but there are either 15 or 16 blue circles (censored patients) in the palifosfamide-doxorubicin arm of the study before median (50%) PFS was reached. Thirty sarcoma patients were enrolled in the treatment arm, so 15-16 blue circles means half the patients were excluded from the analysis before median PFS was reached.

A little bit of patient censoring is relatively common in clinical trials. Censoring, or excluding, half the patients early in the trial (before median treatment effect is reached) is unusual and raises a red flag about the reliability of the data being reported. If those censored patients were included, the PFS reported for the palifosfamide-doxorubicin arm might have been significantly lower. In a larger trial conducted more rigorously, like Ziopharm's phase III study, it's reasonable to expect far fewer censored patients.

Early and frequent patient censoring was also a big problem for Peregrine Pharmaceuticals and the bavituximab second-line lung cancer study.

My fund manager source is further convinced the phase II study results aren't real because if you dig deep into the history of palifosfamide, which stretches all the way back to 1983 and its inventor Robert Struck, you find the drug's chemical structure is inherently unstable. Extrapolating data from ifosfamide papers like Santoro (Journal of Clinical Oncology, 1995) Palifosfamide doesn't penetrate cells well at all, so in order to have any tumor-killing effect, it must be administered at very high doses. Unfortunately, high doses can't be used because the drug causes kidney toxicity.

The palifosfamide dose used by Ziopharm in the phase II and phase III trials is ineffective. Proof? While supposedly increasing tumor response rate from 9% to 23% in the phase II trial, palifosfamide had no effect on other dividing cells such as leukocytes (white blood cells.) The incidence of leukopenia (a side effect of decreased white blood cells) was 17% in the palifosfamide-doxorubicin arm versus 16% in the doxorubicin arm. If palifosfamide was an active drug, the rate of hematological side effects such as leukopenia would be much higher.

Chemically and clinically, palifosfamide makes no sense. Therefore, my fund manager source believes the phase III study in sarcoma fails.

We'll know if he's right next week.

-- Reported by Adam Feuerstein in Boston.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.
3 of 3

Select the service that is right for you!

COMPARE ALL SERVICES
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 17,031.14 +43.63 0.26%
S&P 500 1,984.13 -1.41 -0.07%
NASDAQ 4,518.9020 -48.6960 -1.07%

Brokerage Partners

Rates from Bankrate.com

  • 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