Aeterna Zentaris' (Nasdaq: AEZS) near-term fate lies in the hands of its colorectal cancer treatment, perifosine, but investors got a bit of good news while they wait.

The company's phase 3 trial for AEZS-130, its diagnostic test for adult growth hormone deficiency, or AGHD, seems to have been a success. Orally administered AEZS-130 diagnosed patients just as well as a combination of Serono's Geref Diagnostic and Pfizer's (NYSE: PFE) Ar-Gine, which have to be administered intravenously. Aeterna Zentaris had a Special Protocol Assessment with the FDA, so the agency has already signed off on the trial design.

From a patient's perspective, an oral medication usually trumps one that has to be injected because most patients hate needles, but it's less of an issue for a diagnostic test that isn't given daily. The older drugs do have to be administered over 30 minutes, so the oral administration is more convenient for the person giving the test, which might be a competitive advantage.

Unlike a standard diagnostic test that uses a patient's blood to determine their status, AEZS-130 has to be administered internally, so safety becomes just as important as how well the diagnostic correctly diagnoses a patient. Aeterna Zentaris described AEZS-130 as "safe and well tolerated," so we'll just have to assume that it isn't an issue until we see more data.

Aeterna Zentaris plans to submit its marketing application for AEZS-130 fairly soon, so it'll likely beat perifosine to the market, but I still think the cancer drug is the one to watch. Even though Aeterna Zentaris out-licensed the rights to perifosine to Keryx Biopharmaceuticals (Nasdaq: KERX), I still think it has potential to contribute more to the bottom line than AEZS-130, which Aeterna Zentaris owns entirely. Only about 6,000 adults are diagnosed with AGHD every year. Even if you quadruple that because some patients are going to be tested that aren't positive and assume AEZS-130 takes 100% of the market, it's still a pretty small market. The colorectal cancer market, on the other hand, is a decent size. Bristol-Myers Squibb (NYSE: BMY) and Eli Lilly's (NYSE: LLY) colorectal cancer drug Erbitux brought in over $650 million last year.

You can keep track of Aeterna Zentaris as it tries to gain approval of AEZS-130 and perifosine by adding it to The Fool's free My Watchlist service. Click here to start keeping track of all our Foolish analysis on Aeterna Zentaris.