NEW YORK ( TheStreet) -- Delcath Systems ( DCTH) said Wednesday that its drug/device system to clear tumors from the liver exceeded expectations in a pivotal, phase III study.

Treatment with Delcath's Percutaneous Hepatic Perfusion (PHP) system resulted in a more than 50% reduction in the time-to-tumor progression or death compared to treatment with best alternative care, Delcath said.

The positive results from the phase III study will form the basis of an approval application to the U.S. Food and Drug Administration. Delcath is expected to seek that approval later this year.

Delcath shares closed Wednesday's regular trading session at $10.85. After a brief trading halt, the stock was bid at $11.80 in the after-market session.

PHP is a system that lets doctors isolate the liver from the rest of the blood supply, allowing tumors in the liver to be treated with very high doses of chemotherapy without causing significant toxicity in the rest of the body.

The PHP "system" isolates the liver using a series of catheters, balloon-like clamps and filters that are inserted via small incisions in the neck and legs. Doctors then infuse the liver with the chemotherapy drug melphalan at 10 times the dose they could use if the drug were injected normally. The PHP system filters out the melphalan as it exits the liver, which keeps the toxic drug out of the patient's blood supply and reduces side effects.

Delcath chose metastatic melanoma patients for its first phase III study since this type of cancer often spreads first and foremost to the liver. Ninety-two patients were enrolled, randomized to treatment with either the PHP system or "best alternative care." The primary endpoint was hepatic progression-free survival (hPFS), defined as the length of time before a patient's liver tumor grows, or death.

In the results released Wednesday, patients treated with PHP reported a median hPFS of 214 days compared to 70 days in the control arm, or a benefit of just under five months in favor of the PHP system. The result was statistically significant.

Analyzed another way, treatment with the PHP system reduced the risk of tumor progression and/or death by 54% compared to the best alternate care.

"We believe that these data support that the Delcath PHP System may provide a significantly better treatment option for patients suffering from melanoma metastases in the liver," said Eamonn Hobbs, Delcath's CEO and president.

-- Reported by Adam Feuerstein in Boston.

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