The performance of a health care stock during the first week of trading is sometimes a good indicator of how it will perform for the year. I believe this pattern might be the result of bigger players positioning themselves for the year by dumping stocks they think will under-perform.

As such, the first week of trading might be indicative of the market's overall confidence in a given stock. Taking a look at the broader picture, it's interesting that some health-care stocks lifted off last week, while others sank for mysterious reasons. So with that in mind, here is my take on why Inovio Pharmaceuticals (NASDAQ:INO) and Rockwell Medical Technologies (NASDAQ:RMTI) were the biggest laggards in health-care during the first week of trading.

Is Inovio too risky?
Shares of the DNA vaccine maker Inovio fell more than 15% last week on unusually high volume, making it one of the worst performers in the sector. Drops like that are usually linked to a material event, yet nothing came across the wires that should cause investors to worry.

Instead, this downturn is only the latest wild swing in the company's share price. Over the past year, Inovio has risen roughly 380%, but has done so in nauseating fashion. In the past six months, investors have seen Inovio shares break through $3 three different times, only to see share price fall precipitously afterwards.

So my take is that this recent drop is little more than a continuation of this year-long trading pattern. Looking ahead, Inovio does have a mid-stage trial readout for its human papillomarvirus, or HPV, vaccine VGX-3100 that could help bring some stability to the company's shares. 

What's interesting is that Inovio's peer in the vaccine space, Novavax (NASDAQ:NVAX) is rapidly closing in on a $1 billion market cap figure and has been spared the wild swings in share price, even though it's at a similar developmental stage.

While Novavax is receiving payments from its BARDA contract that is clearly helping to drive share price appreciation, I believe the primary difference between the two companies is the uncertainty surrounding Inovio's vaccine platform. Novavax's nanoparticle platform has been validated through the approval of GlaxoSmithKline's HPV vaccine Cervarix, as well as the company's own successful mid-stage trials.

By contrast, Inovio's DNA-based approach is marked by a history of clinical failures, and the company is fighting to reverse this trend. So until Inovio validates their approach, you should expect more wild swings like last week.

Has the market lost confidence in Rockwell Medical?
Rockwell Medical was looking to have a banner year in 2013 after its shares rose nearly 400% in a few months' time. However, the market apparently lost confidence in the company's dialysis-induced iron deficiency drug, triferic, after Brean Capital issued a note saying the drug won't be approved in 2014. Namely, Brean's analyst on the matter, Jonathan Aschoff, questioned Rockwell's trial design, as well as the drug's effectiveness.

Even so, triferic did meet both its primary and secondary endpoints in late-stage trials, which will be used to support a New Drug Application with the Food and Drug Administration early this year. I think it's also important to understand that there is always debate over a drug's chances with the FDA. Sometimes the naysayers are right, sometimes they are way off base. Time will tell. 

Looking ahead, Rockwell Medical will be in trouble if triferic isn't approved, however. With only about $30 million in cash remaining, and a near stalemate between revenue and costs, Rockwell needs another revenue driver or shares are likely to head south in a hurry. Given that a regulatory decision isn't expected until year's end, you might want to wait on the sidelines for now.

Foolish outlook
I believe the negative view of Inovio and Rockwell in the first week of trading is a bellwether of sorts for each company. In Inovio's case, the market is unconvinced that the company has solved the riddle of DNA vaccines, and speculators have started to jump ship. Rockwell, on the other hand, is in for a rough year ahead of its regulatory review for triferic. Last week's drop might be a sign of things to come.