Have you checked your 401(k) or IRA balance lately? If you're like many people, the numbers brought forth a smile, with the major indexes hitting record highs. But if you had significant stakes in some health-care companies, frowns were more in order. Here are three of the most horrendous performers this week.

End of the road

It's the end of the road. That's the message from Ziopharm Oncology (TCRT -1.67%) concerning palifosfamide as a potential treatment for metastatic soft tissue sarcoma. The biotech's shares plummeted more than 60% this week after disappointing news from a late-stage clinical study of the drug.

After the drug failed to improve progression-free survival in the study, Ziopharm CEO Jonathan Lewis bluntly said that, "There is no way this drug will get to approval in any country in the world." The company announced that it was scrapping the palifosfamide program as a result of the clinical results, despite a recommendation from its independent data monitoring committee to move ahead with an analysis on possible effects of the drug on overall survival. 

While a colossal failure like this is really bad news, it could have been worse. Ziopharm does at least have other drugs in its pipeline that could be successful down the road. The company said that it was now refocusing on its synthetic biology program, particularly Ad-RTS IL-12, which is in mid-stage trials, and targeting treatment of advanced melanoma and breast cancer. 

Too slow, too bad
Shares in Idenix Pharmaceuticals (NASDAQ: IDIX) fell 22% this week. This latest decline extends a 62% fall for the stock over the past year.

Bad news from the U.S. Patent and Trademark Office, which was announced last weekend, served as the culprit. The patent office found that Gilead Sciences (GILD 0.07%) beat Idenix to the punch in filing for a patent for a new hepatitis C treatment. That's not the end of the matter, though. Another decision is yet to come on which company actually invented the treatment first.

Idenix said that it doesn't think that patent application is relevant to any of its products currently in development. This decision also doesn't impact any of the several other patent disputes that the company has with Gilead.

A big hole to fill
Managed-care companies don't often make our list of horrendous health-care stocks, but Vanguard Health Systems (NYSE: VHS) proved to be an exception this week. Unwelcome news from the Grand Canyon state left the company with a big hole to fill. Shares fell nearly 11% for the week.

Vanguard announced on Sunday that it failed to gain a new contract with Arizona's Medicaid agency. The company's current contract expires on Sept. 30 of this year. Vanguard's Phoenix Health Plan had served the Arizona Medicaid program for almost 30 years.

While the loss decimates the Phoenix Health Plan's business segment, Vanguard can fall back on several other sources of revenue. The company owns and operates 28 acute care hospitals, and has managed care plans in three other locations.

Comeback kid
Which of the three horrendous stocks of the week is most likely to stage a nice comeback? I have to go with the one with the least amount to make up -- Vanguard Health. Ziopharma is a long way off from even the potential of launching a product. Idenix has at least one drug on the market, but any other possible commercial success is well in the future.

Vanguard's hospitals and other managed care plans could do well under Obamacare -- and it still has the option to appeal the Arizona decision. I wouldn't recommend buying the stock, though. There are plenty of better picks out there. But, for the least worst of the worst for this week, Vanguard's the best bet.