FDA approves sale of nuc med agent for imaging appendicitis

The FDA has given the go-ahead for Mallinckrodt Imaging and its strategic collaboration partner, Palatin Technologies, to begin marketing the radiopharmaceutical NeutroSpec, the first such agent approved by the agency to identify infection in more than two decades.

The announcement came July 7 in a conference call hosted by Palatin of Cranbury, NJ. The product initially will be used as a scintigraphic imaging agent for patients age 5 and older who present with signs and symptoms of appendicitis. In noting that marketing of NeutroSpec would begin during the coming weeks, Palatin estimated peak sales from the drug, based on 100,000 procedures, to hit $75 million to $100 million annually within five years.

"FDA approval of NeutroSpec is a milestone resulting from four years of work," said Carl Spana, Ph.D., Palatin's president and CEO. "The company is now positioned to realize revenue from product sales for the first time, a transition that few biopharmaceutical companies ever make."

Palatin's product team will now devote its full attention to PT-141, a nasally administered peptide designed to treat sexual dysfunction. He expressed confidence that PT-141 also would receive FDA approval.

NeutroSpec actually dates back more than four years, to 1999, when Palatin entered into an agreement with Mallinckrodt to exclusively market and distribute the product throughout North and South America and Asia Pacific markets. The following year, an FDA advisory committee found the agent, then called LeuTech, to be safe and effective for use in diagnosing appendicitis in patients with atypical symptoms.

The radiopharmaceutical is designed to determine definitively whether appendicitis is the cause of such suspicious but nonspecific symptoms. About half the 700,000 patients in the U.S. with suspected appendicitis lack typical symptoms such as pain and tenderness in the right lower abdomen, fever, nausea, and an elevated white blood cell count, said Dr. Frederick Weiland, an associate clinical professor of radiology at the University of California, Davis, and codirector of nuclear medicine at Sutter Roseville Medical Center in Roseville, CA. The new product enables clinicians to diagnose appendicitis within five or 10 minutes, Weiland said.

In May, LeuTech was renamed NeutroSpec at the request of the FDA, which suggested a name change would minimize the possibility that the drug would be confused with other product names that look or sound the same. The big news came July 2, when Palatin was notified that the FDA had approved NeutroSpec.

NeutroSpec consists of a murine monoclonal antibody formulated for labeling with the radioisotope technetium-99m. The labeled antibody binds to circulating and sequestered neutrophils, cells that defend against and congregate at the site of infection.

"Traditionally in nuclear medicine, the process of labeling white blood cells has been laborious," said Weiland, a NeutroSpec investigator who participated in Palatin's phase III clinical trials.

A marketing plan will be implemented when labeling for the drug is completed, according to Steve Hanley, president of Mallinckrodt. This should be done in a few weeks. Spana said the per-dose cost might range from $500 to $1000.

"The community of nuclear medicine physicians, a small one, has been awaiting this product for a long time," Hanley said. "Our representatives and pharmacy personnel throughout the country have been well trained and are ready to educate them about the benefits of NeutroSpec. Our (marketing) message is pretty clear-this is rapid, safe, and simple."

Mallinckrodt will market and distribute NeutroSpec through the company's Maryland Heights, MO, distribution center and its network of U.S. radiopharmacies. Mallinckrodt is a business unit of Tyco. Continuing education programs will be developed in an effort to market the product by educating clinicians, Hanley said. The product initially will be marketed to nuclear medicine physicians and radiology departments.

"Our (marketing) message will be very clear-this (test) is rapid, safe, and simple," he said.

Spana expects no problems in getting this message across.

"The nuclear medicine community isn't overly large, so we can get to a lot of them in peer-to-peer contact," he said. "Considerable time has been spent training the technical sales staff."

Palatin may seek to expand the labeling beyond appendicitis, according to Spana. Potential applications include bone infections and postsurgical infections. Clinical trials to support other applications are expected to begin by the first quarter of 2005.

"We are now discussing with the Mallinckrodt Imaging team which applications we want to address in the pivotal trials," he said. "We are also working with the FDA to finalize our clinical development plan so that we can seek a broad-section imaging label for the product without having to go indication by indication. I think we will be successful there as well."

Palatin has a strong balance sheet with cash, cash equivalents, and short-term investments totaling $27.2 million. With FDA approval now in hand, the company has high hopes for the rest of this year and beyond.