FDA advisory panel nixes approval of drug-device for liver metastases

SILVER SPRING, MD. – The risks outweigh any possible benefits of treatment with a drug-device combination that delivers melphalan directly to the livers of patients with liver metastases from ocular melanoma, a Food and Drug Administration advisory panel concluded in a 16-0 vote.

At a meeting of the FDA’s Oncologic Drugs Advisory Committee, several panelists said that the treatment was promising but should remain investigational, given its marked toxicity and lack of effect on overall survival.

The Melblez Kit is a combination of melphalan and the Delcath Hepatic Delivery System, which includes two catheters and an extracorporeal hemofiltration component. The catheter is used to administer high doses of the chemotherapy drug directly to the liver via the hepatic artery, and the hemofiltration component lowers the drug level before the blood is returned to the systemic circulation, according to the manufacturer, Delcath Systems. Patients are hospitalized for about 4 days for the procedure, which takes about 3 hours and is performed at 4-week intervals under general anesthesia.

There are no FDA-approved treatments for patients with unresectable metastatic ocular melanoma to the liver, which is the indication under FDA review.

Treatment with the kit was associated with antitumor activity, but it also was associated with fatal and life-threatening adverse reactions. There was a trend towards a detrimental effect on survival, and the risk evaluation and mitigation strategy (REMS) proposed by the company to address those risks "will not improve the observed benefit-risk profile," Dr. Geoffrey Kim, a medical officer in the FDA’s office of hematology and oncology products, told the panel.

In an open-label, randomized multicenter phase-III study conducted between 2006 and 2010 in the United States, the device was used to treat 44 patients. Their outcomes were compared with those of 49 matched patients given the best alternative care (BAC). All patients had surgically unresectable hepatic-dominant metastatic ocular or cutaneous melanoma (89% had ocular melanoma, and almost half were treated at the National Cancer Institute). Subjects were treated until their hepatic disease progressed. The dose administered with the Melblez Kit was 3.0 mg/kg for a median of three treatment cycles and a median of 120 days; best alternative care included systemic chemotherapy in 49% of patients and intrahepatic chemotherapy in 22%.

The primary end point, median hepatic progression-free survival (hPFS) was 7 months among those on the device, compared with 1.6 months among those on BAC, a statistically significant difference that represented a 61% reduction in risk (hazard ratio, 0.39), according to the company. The median overall PFS was 4.8 months among those treated with the device, compared with 1.6 months among those on BAC, also a statistically significant difference.

Overall survival was comparable: 9.8 months in the device-treated group and 9.9 months in those on best alternative care. Further, almost 80% of patients in the Melblez Kit arm had a serious adverse event and almost 70% had a grade-4 adverse event. With best alternative care, the rate of serious adverse events was 16% and the rate of grade-4 events was 2%. No patients on best alternative care died because of an adverse event. Three patients treated with the drug-device died from adverse events.

The adverse reactions in a combined population of 121 patients in the phase-III and phase-II studies and in 28 patients in the BAC arm who crossed over to treatment with the device included toxic deaths in 7% (including cases of hepatic failure, streptococcal sepsis, and GI hemorrhage), cerebral infarction in 4%, MI in 2%, and grade-4 bone marrow suppression with a median time to recovery of more than 1 week in more than 70%. About half had to be rehospitalized for an adverse event.

For a cancer treatment, this safety profile "is unprecedented, in terms of the toxicity," Dr. Richard Pazdur, director of the FDA’s office of hematology and oncology products, remarked.

After the vote, panel member Dr. Louis Diehl, professor of medicine at Duke University, Durham, N.C., said that progression-free survival is valued in studies as an indicator of improved quality of life and it can be an early marker of increased survival. "Unfortunately, this treatment has an increase in morbidity and an increase in mortality and I can’t see from the survival curve that it will ever translate into an improvement in survival."

Delcath did not issue a response after the panel’s vote.

The FDA usually follows the recommendations of its advisory panels. Panelists have been cleared of potential conflicts of interest related to the topic of the meeting, although a panelist may occasionally be given a waiver. At this meeting, two panelists who had expertise in the topic were given waivers (one panelist is the principal investigator in a study of a competing device and the other works at a medical center where a study of a competing device is being conducted).