The US Federal Trade Commission has approved Bristol-Myers Squibb’s $74 billion takeover of biotech Celgene by a vote of 3 to 2. The biggest merger in the history of the global pharmaceutical industry values the US biotech at around $90 billion, including debt.

With all regulatory requirements satisfied, BMS said it expected to complete the transaction on Nov. 20.  In return for its approval, the FTC mandated that the merged company sell Celgene’s blockbuster psoriasis drug Otezla.

Without the divestment, the FTC said the acquisition would harm consumers in the US market for treatments taken orally for moderate-to-severe psoriasis Bristol Myers Squibb’s phase 3 TYK-2 inhibitor BMS-986165 is regarded as the most advanced oral treatment that could compete directly with Otezla.

Celgene is selling the drug – which is not yet on the market – to Amgen for $13.4 billion. The divestment is another superlative, being called the largest divestment ever mandated by the FTC or the US Department of Justice.

The antitrust agency apparently is skeptical that Amgen was the right buyer. While saying that the drugmaker has the expertise, US sales infrastructure and resources to restore the competition that would otherwise be lost, it reserved the right to cancel the sale and force a better deal if it finds Amgen’s marketing efforts inadequate.

Industry watchers noted that the FTC’s vote was split along US political party lines, with the Republican majority prevailing.

Commissioner Rohit Chopra, a consumer advocate, reportedly challenged the agency’s usual approach of examining only product overlap when reviewing pharma mergers and called for a closer look at whether a deal would magnify anticompetitive behavior such as patent abuse or deter innovation from small biotech firms.

The merged drugs group will have nine products with more than $1 billion in sales and near-term launch opportunities with revenue potential of more than $15 billion. Launches anticipated in the medium term include two immunology and inflammation products and four hematology drugs.