Sure, the data wasn't exciting enough to cause an overnight three-bagger, like Rigel Pharmaceuticals' (NASDAQ:RIGL) previous announcement of clinical trial results did, but investors should have been a little more excited than they were about the drug developer's most recent data.

Rigel had previously proved its Syk inhibitor, R788, successful against rheumatoid arthritis, but the company's also testing it in patients with B-cell lymphoma and immune thrombocytopenic purpura (ITP). In each of these diseases, the body's immune system has fallen out of whack. By inhibiting the Syk protein, Rigel hopes to calm down the overactive cells.

Yesterday's data, which was presented at the International Conference on Malignant Lymphoma, showed that R788 slowed the disease in patients with two types of lymphoma -- small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) and diffuse large B-cell lymphoma (DLBCL).

These patients were fairly far along in their disease progression, having previously failed in their front-line chemotherapy regimens. Some had even failed with Genentech (NYSE:DNA) and Biogen Idec's (NASDAQ:BIIB) second-line treatment, Rituxan, so a partial response in some patients is good enough at this point.

R788 didn't show a response in all the lymphomas tested, and while you'll likely hear me and my Foolish colleagues clamoring about how subset analysis is generally bad, it's considerably more acceptable in phase 2 studies. That's because there's still time to work things out and test a hypothesis in the phase 3 trial, or even another phase 2.

Rigel didn't say what its next move would be, but I'd guess it will run another phase 2 trial -- just with patients diagnosed with the SLL/CLL and DLBCL subtypes.  

If approved, the use of R788 in rheumatoid arthritis is likely to be the big moneymaker for Rigel -- especially since it's an oral agent that would compete against drugs given by injection and transfusion, like Abbott Laboratories' (NYSE:ABT) Humira or Johnson & Johnson's (NYSE:JNJ) Remicade. But this early data for its use in lymphoma should give investors hope that the drug might be approved for a second indication.