Gilead to pay Assembly Bio an initial $100 million as part of 12-year partnership to develop antiviral drugs

Gilead Sciences Inc.
GILD,
+2.00%
announced Tuesday a 12-year partnership Assembly Biosciences Inc.
ASMB,
+2.11%
to develop antiviral therapies, with an initial focus in hepatitis B virus and hepatitis D virus. As part of the partnership, Gilead will pay Assembly $100 million, including $84.8 million upfront and a $15.2 million equity investment. Assembly’s stock was halted for news until 7:30 a.m. Eastern, while Gilead shares were still inactive. The equity investment represents 19.9% of the voting stock of Assembly. Separately, Gilead has agreed to buy up to 29.9% of Assembly’s voting stock at a premium. And Assembly will be eligible to receive up to $330 million in regulatory and commercial milestones, and be eligible to receive three separate $75 million collaboration extension payments. Gilead has the right to appoint two people to Assembly’s board of directors. Assembly’s stock has tumbled 35.8% over the past three months through Monday, while Gilead shares have gained 2.2% and the S&P 500
SPX,
+1.06%
has slipped 3.3%.