Arrowhead Reports Partial Clinical Hold For ARC-50 Phase 2b Study - Quick Facts

(RTTNews) - Arrowhead Research Corp. (ARWR) said that the U.S. Food and Drug Administration or FDA verbally informed it in a preliminary call of a partial clinical hold, under which the company is cleared to begin a modified multiple-dose study of ARC-520 in patients with chronic hepatitis B infection.

Arrowhead's RNAi-based candidate ARC-520 is being investigated in the treatment of chronic HBV infection. About 350million to 400 million people worldwide are chronically infected with the hepatitis B virus, which can lead to cirrhosis of the liver and is responsible for 80 percent of primary liver cancers globally.

The FDA has requested Arrowhead Research to start the multiple-dose Phase 2b study at 1 mg/kg of ARC-520 rather than the proposed parallel study design of 2 and 4 mg/kg, and requested additional information be provided to the agency.

The additional information includes a final study report from the single-dose Phase 2a study in patients who received 1-4 mg/kg ARC-520, which is ongoing and has not reported any serious adverse events or evidence of end organ toxicity to date.

The FDA has also requested a final study report from an ongoing multiple-dose non-clinical study, which has shown ARC-520 to be well tolerated with no evidence of end organ toxicity to date.

Arrowhead Research noted that the FDA committed to provide with a letter detailing its thoughts and requests within 30 days. The ongoing Phase 2a study is continuing as planned, and the company expects to file with Asian and European agencies to begin additional Phase 2b studies in the coming weeks.