Avanir Pharmaceuticals' (Nasdaq: AVNR) first full quarter marketing Nuedexta was only marginally better than the quarter it launched in. Net sales of Neudexta were just $1.9 million, which is an improvement from $0.5 million last quarter, but it's still a far cry from a successful drug.

The problem is that Neudexta isn't like other orphan drugs such as BioMarin Pharmaceuticals' (Nasdaq: BMRN) Naglazyme, Alexion Pharmaceutical's (Nasdaq: ALXN) Soliris, and Regeneron Pharmaceuticals' (Nasdaq: REGN) Arcalyst that treat diseases directly. Neudexta treats uncontrollable outbursts of crying or laughing that's a symptom of neurological diseases or injuries to the brain in some patients.

The disease technically has a name -- pseudobulbar affect -- but doctors treating the patients are more focused on the underlying cause: Lou Gehrig's disease, Parkinson's disease, multiple sclerosis, and others. Although I imagine pseudobulbar affect is rather embarrassing, it's not an immediate life-threatening aspect of the disease.

On the conference call, management spouted off some numbers suggesting that the more often its sales force visits a doctor, the more likely the doctor is to prescribe Neudexta. Educating doctors about pseudobulbar affect takes "time and effort."

Time is always a precious commodity for biotechs. The company burned through $14.5 million in the third quarter and had just over $90 million in the bank. That's only six quarters of cash, but hopefully Avanir can keep increasing sales, which will lower its burn rate.

The prescriptions for Neudexta grew 16% month over month from May to June, which is a solid 56% quarter-over-quarter growth rate. If Avanir could keep up that rate, it could be at a run rate of about $100 million annually in about six quarters, which isn't too shabby for a company with a sub-$400 million market cap.

I think investors should give Avanir a little more time. But keep a close eye on that prescription data, because it'll determine whether you'll be crying uncontrollably or be laughing all the way to the bank.

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