NPS Pharma: Gattex FDA Panel Preview

BEDMINSTER, NJ ( TheStreet) -- NPS Pharmaceuticals ( NPSP) has two major questions to tackle at next week's FDA advisory panel that will review Gattex for the treatment of patients with short bowel syndrome.

1. Does Gattex cause cancer?

2. Does a reduction in intravenous feeding (but not necessarily a cessation of intravenous feeding) represent a significant and meaningful clinical benefit for patients with short bowel syndrome?

The Gattex FDA advisory panel is scheduled for Tuesday, Oct. 16. On Friday, Oct. 12, FDA is expected to release briefing documents for panel including the agency's clinical review of Gattex.

NPS Pharma shares closed Wednesday at $9.17.

Short bowel syndrome (SBS) is a chronic and disabling condition that strikes people, who for various reasons including Crohn's disease, have about 50% of their lower intestines surgically removed. A majority of patients can adapt to lead normal lives. A smaller group of SBS patients never recover full functionality of their lower intestines, and a result, must spend the rest of their lives attached to an intravenous parenteral nutrition bag that provides the liquid nutrients they need to survive.

NPS Pharma estimates approximately 15,000 SBS patients eligible for Gattex in the U.S., meaning the condition qualifies for orphan drug status (and potential premium pricing.) Gattex pricing hasn't been disclosed but drug's U.S. peak sales potential is in the $350 million range.

European regulators approved Gattex last month. Takeda will sell the drug in Europe under the brande name Revestive. NPS Pharma receives royalties on Revestive sales.

Gattex is an analogue of GLP-2, a protein involved with intestinal growth and function. Administered via a shot under the skin, Gattex is designed to boost the ability of the intestine to absorb nutrients.

Approximately 556 SBS patients have been treated with Gattex in all studies. One year ago, NPS Pharma reported three cases of cancer in Gattex-treated SBS patients from a long-term follow-up study. Two of the patients died. Gattex is a growth factor so the three cancer cases raised concerns that the drug may be carcinogenic, particularly when used over long periods.

One patient died from a metastatic adenocarcinoma that likely originated in the gastrointestinal tract. This patient was being treated with Gattex for 313 days when the cancer was diagnosed. However, the patient was previously diagnosed with Hodgkin's disease and treated with radiation and chemotherapy. A CT scan taken six months before the patients began taking Gattex revealed a lesion on the liver.

The second patient was diagnosed with non-small cell lung cancer 85 days after starting treatment with Gattex. This patient, who also died, was a heavy smoker.

The third patient was diagnosed with squamous cell lung cancer after 535 days on Gattex therapy. This patient also had a history of smoking.

At the FDA panel, NPS Pharma will argue that the three cancer cases are unrelated to Gattex. Patients in the Gattex study were pre-screened with colonoscopies and any polyps found were removed. At the end of the study, no difference in the number of new polyps was observed between Gattex-treated patients and patients in the placebo arm. None of the new polyps that were found were cancerous.

A two-year rat carcinogenicity study of Gattex was performed with clean results. A similar study in mice is still being conducted but NPS Pharma has an agreement with FDA to finish the study after Gattex is approved.

European regulators reviewed all these safety data and found no link between Gattex and cancer.

SBS patients rely on intravenous feeding -- known as parenteral nutrition -- for the liquid nutrients they need to survive. The average SBS patient enrolled in the NPS Pharma studies required approximately 12 liters of parenteral nutrition per week. Gattex works by increasing the nutrient absorption rate of the intestines, thereby reducing the amount of parenteral nutrition that SBS patients require.

In the phase III study, 63% of SBS patients responded to treatment with Gattex after six months compared to 30% of similar patients treated with a placebo. This outcome -- the study's primary endpoint -- was highly statistically significant. Response was defined as a 20% or greater reduction in weekly parenteral nutrition volume.

The phase III study was not conducted under a Special Protocol Agreement with FDA although NPS Pharma has said FDA officials were consulted on the trial design and agreed with the primary endpoint used.

In other analyses of the trial data, Gattex-treated patients reduced their average weekly parenteral nutrition requirements by 4.4 liters, or a 35% reduction. By comparison, placebo patients reduced their parenteral nutrition by 2.3 liters, or 17%. The difference between the two groups was also statistically significant.

Also, 54% of Gattex patients were able to reduce the number of infusion days per week by one or more days, more than double the 23% reduction for placebo-treated patients. Mean body weight of Gattex-treated patients remained unchanged.

Whether or not reductions in parenteral nutrition represent a meaningful clinical benefit for SBS patients is likely to come up as a topic of discussion and debate at next week's FDA advisory panel. European regulators debated the same question and concluded that Gattex provided a meaningful clinical benefit for SBS patients.

Weaning off parenteral nutrition entirely is the best outcome for SBS patients. To date, 8% of Gattex-treated patients have achieved this goal. None of the placebo patients have done so. These patients were treated with Gattex for one year or more.

The FDA drug approval decision date for Gattex is Dec. 28.

--Written by Adam Feuerstein in Boston.

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Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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