In a deal with terms that could add up to almost $2 billion, Abbvie Inc. and I-Mab Biopharma Co. Ltd. plan to develop and commercialize the anti-CD47 monoclonal antibody lemzoparlimab for treating multiple cancers.

Lemzoparlimab, also called TJC-4, is Shanghai-based I-Mab’s discovery. The company will get an up-front $180 million by licensing the highly differentiated antibody to Abbvie, along with a $20 million milestone payment based on phase I results.

The biggest payoff is the $1.74 billion in success-based milestones, $840 million of which is pegged to  achieving clinical development and regulatory approval milestones. The remainder is based on commercial milestones. Should lemzoparlimab be commercialized, Abbvie will pay I-Mab tiered royalties from the low- to midteen percentages on global net sales outside of China.

In early trading, I-Mab’s stock (NASDAQ:IMAB) climbed to $41.87 per share but had settled to about $37, a rise of about 3.5%. On Jan. 17, shares went for $12.50 and have been on a steady 196% rise since then.

It’s been an eventful year for I-Mab, starting with its $104 million IPO on Nasdaq in January. The company made progress in developing nearly all its clinical-stage assets. TJC-4 is the first. It received an IND approval from the FDA in January 2019. In early April, the first participant was dosed in I-Mab’s phase I/II study of TJC-4 in treating relapsed/refractory acute myeloid leukemia and myelodysplastic syndrome.

This isn’t the first deal I-Mab has cut for TJC-4. Nearly year ago, on Sept. 23, I-Mab and Merck & Co. Inc. (MSD) agreed to evaluate the combination of TJC-4 and MSD’s anti-PD-1 therapy, Keytruda (pembrolizumab), in patients with multiple cancer types.

North Chicago-based Abbvie’s stock (NYSE:ABBV) was calm about it all at midday, trading at about $91 per share at a barely perceptible drop in value of less than a half percentage point. However, stepping back, the stock is about 50% stronger than it was on Sept. 5, 2019, when shares went for $61.03.

There are only a few anti-CD47 treatments in early clinical stage. Among the Chinese players, Jiangsu Hengrui Medicine Co. Ltd.’s SHR-1603 won IND approval to initiate a phase I trial in patients with advanced solid tumors or relapsed/refractory malignant lymphoid diseases. Immuneonco Biopharmaceuticals (Shanghai) Co. Ltd. said in May 2019 that its IMM-01 was granted IND approval in China to investigate its efficacy for leukemia.