Chelsea Therapeutics (NASDAQ:CHTP) won’t meet with regulators until later this month to discuss its orphan drug Northera but the company is already staking out scenarios of a more limited approval for the drug.

If results of an ongoing phase 3 study don’t support the durability of Northera’s effect over time, the company said in its quarterly filing that it “might seek to obtain approval for Northera as an acute rather than a chronic treatment.” That change, detailed in an updated list of risk factors for the company, would further limit use of a drug that was already intended for a narrow patient population.

 

Northera, which failed to gain U.S. Food and Drug Administration approval in March, was developed to treat neurogenic orthostatic hypotension, or NOH, a condition characterized by dizziness and fainting upon standing due to low blood pressure. The condition can be found in patients with Parkinson’s disease, multiple systems atrophy and pure autonomic failure. Chelsea has said that the number of U.S. patients who have NOH is estimated at just 80,000.

Charlotte-based Chelsea did not hold a conference call to discuss first quarter financial results, saying that a call would be held after the company meets with the FDA. That meeting will happen this month though Chelsea did not specify the date.

The FDA meeting will be the first formal discussion on Northera since Chelsea received a March 28 complete response letter for the drug. The drug’s durability was cited as a a factor in the FDA’s decision declining approval. The FDA asked Chelsea to provide more data on Northera’s durability over a two to three month period. Northera’s durability was also questioned during the FDA staff review of the drug application. Clinical trials did not show Northera’s effects lasted longer than four weeks.

Chelsea plans to address the FDA’s durability questions with data from an ongoing clinical study. But the company acknowledged that this study may not meet the FDA’s requirements. The study was originally intended to support Chelsea’s Northera drug filing but was modified last year with a new goal of testing whether the drug reduced falls in Parkinson’s patients who have NOH. Chelsea was advised that reducing falls could be added in a label change if the drug was approved. Now Northera approval may hinge on this study — if the FDA accepts this study as being enough. Chelsea said that it might need to modify the study or conduct a new one altogether. The company won’t know more details on what the FDA wants until it meets with the agency. Chelsea expects to get formal meeting minutes by the end of the month. Afterward, Chelsea plans to hold a conference call to discuss the meeting and the company’s next steps for Northera.