Human Genome Sciences and GlaxoSmithKline are planning the launch of lupus drug Benlysta, and step one involves building a sales force to call on rheumatologists.

“We’ll be able to reach key prescribers with a pretty small, focused bunch,” said Barry Labinger, EVP and chief commercial officer at Human Genome, adding that other sales forces for autoimmune diseases treated by rheumatologists are on the order of 150 reps.  “Certainly we wouldn’t need more than that.”

Human Genome and GSK are partners in a 50-50 collaboration on Benlysta, which appears to be emerging from development in fine shape: data from a second Phase III study, released last month, show the drug performed well compared to placebo, with a favorable safety profile.  

Professional messaging, being handled by McCann agency echoTorre Lazur, is likely to key in on Benlysta’s ability to meet criteria borne out in the R&D:  proven efficacy and the ability to treat long term without significantly increased safety risk.

The next hurdle is regulatory approval.  Reps could hit the street as soon as the second half of 2010, assuming Human Genome files with FDA early next year and the agency grants priority review.

Barclays Capital’s Jim Birchenough expects launch in early 2011, forecasting peak sales of $3 billion. To reach the 200,000 patients Human Genome says are being treated by rheumatologists for the moderate-to-severe form of lupus erythematosus, the companies have tapped online patient groups and are considering social media, but not classic DTC.

 “I don’t think we’ll be doing mass media DTC,” Labinger said.  “We’ll be more targeted.”