When Delcath designed the phase III study, it assumed patients treated with BAC would report median hPFS of about four months compared to about seven months for Melblez. Why did BAC underperform expectations so significantly? It will be interesting to read the FDA analysis of what constituted BAC in this study and whether the treatments used constituted a real comparator.
I'd also like to see the hPFS data excluding the 11% of patients with cutaneous melanoma since they're no longer being considered for approval under the amended Melblez application. I don't expect the results to change significantly but Delcath has never reported these data before.
I expect FDA and the advisory panel to raise significant concerns about Melblez's safety. Three patients out of 40 died due to Melblez during the phase III trial -- two from neutropenic sepsis and one from hepatic failure. That's a 7.5% mortality rate attributed to Melblez -- not the underlying cancer. Melblez is a risky procedure.
I also question the ability of the filters used in Melblez to keep melphalan from leaking outside the liver. Sixty-one percent of patients treated with Melblez reported serious (grade 3 or 4) neutropenia, 74% reported serious thrombocytopenia and 46% reported serious anemia.
Delcath changed out the filter in Melblez but the company hasn't disclosed any new safety data. (Although the company claims the "Gen 2" filter is better.) On a conference call Wednesday night, Delcath executives said the FDA advisory panel would spend considerable time reviewing the company's proposed risk-management plan for Melblez. To me, this is a tacit acknowledgment that Melblez's safety is a regulatory concern.
The road leading to the May 2 FDA advisory panel has been rough for Delcath. Remember, Melblez was first submitted for FDA approval in late 2010. FDA issued a refuse to file letter, requiring Delcath to re-submit with additional manufacturing and safety data. We have never seen these new safety data. Delcath has not been as transparent with Melblez data as I'd prefer, so I won't be surprised to see some unpleasantness aired by FDA when the briefing documents are posted publicly.