NEW YORK (CNN/Money) - Two drug candidates that would reduce the symptoms of rheumatoid arthritis have passed testing, announced drug manufacturers Human Genome Sciences, Roche, Genentech and Biogen Idec on Wednesday, offering hope where arthritis treatments have raised health concerns.

Mab Thera met its critical endpoint in phase III testing and data will soon be submitted to European health authorities, according to Swiss firm Roche (up $1.62 to $107.56, Research), which tested the product in conjunction with partners Genentech (up $1.13 to $58.28, Research) and Biogen Idec (up $0.47 to $35.24, Research). If successful, the drug would help prevent cartilage and bone erosion resulting from arthritis. Stock prices for the drug developers rose more than 1 percent on the news.

Mab Thera is the same product as Rituxan, a Genentech-produced drug that has been sold in the U.S. since FDA approval in 1997. Rituxan was Genentech's top-selling drug last year with $1.7 billion in sales, nearly half the company's total drug sales of $3.7 billion.

Genentech spokeswoman Megan Pace said Rituxan treats patients of non-Hodgkin's lymphoma in the U.S. If approved as Mab Thera in Europe, the drug could be used to treat patients with rheumatoid arthritis for whom other treatments have been unsuccessful. (See correction) "We are excited about these results and there's an unmet need for these patients," said Pace. "They are very difficult to treat. They have already failed on other medications."

A separate drug candidate, LymphoStat-B, met primary endpoints in phase II clinical trials, announced Human Genome Sciences (up $0.79 to $10.05, Research). The Maryland-based company said that the product demonstrated efficacy and safety for use in patients with rheumatoid arthritis. The company, which does not yet have any products on the market, saw share price rise more than 4 percent following the news.

"This was a very demanding study in terms of trial design," said Human Genome Sciences spokesman Jerry Parrott. "These are good results. The drug appears to be safe and well tolerated."

Like Mab Thera, LymphoStat-B was tested on patients who have failed previous drug treatments, said Parrott.

If Mab Thera is approved by the European Health Authority, Europe's version of the FDA, that would likely mean a rise in revenue for Genentech, though most of the revenue would probably go to Basel-based partner Roche, said Argus Research analyst John Eade.

"It certainly is a positive for Genentech but I'm sure the setup they have with Roche gives Roche the lion's share for global [non-U.S..] sales," said Eade.

Nonetheless, millions of patients suffer from rheumatoid arthritis worldwide and the money-making

potential for a successful treatment is promising. "There's a lot of competition here but the field is wide open, especially with the recent development with Vioxx and Celebrex," said Eade.

Arthritis treatments have generally been viewed as a lucrative growth area for drug makers, especially as the Baby Boomer generation ages. However, there have been problems in the product area recently.

Merck & Co. pulled leading arthritis-related painkiller Vioxx off the market Sept. 30, citing doubled risk of heart disease. Pfizer announced Dec. 17 that it would not be removing arthritis treatment drug Celebrex from the market, even though the product had raised similar health concerns.

Correction: An earlier version of this story incorrectly referred to non-Hodgkin's lymphoma and rheumatoid arthritis as the same disease. CNN/Money regrets the error.