Pfizer is near a deal to combine its off-patent drugs division — which includes best-selling treatments like Viagra — with Mylan, the maker of the EpiPen emergency allergy treatment, to create a new giant in the business of drugs without patent protections, two people briefed on the matter said.

A deal could be announced as soon as Monday, according to these people, who were not authorized to speak publicly about the confidential discussions.

The generic-drug industry has suffered for years in the face of falling prices, a trend that is often overlooked as many Americans struggle with paying for brand-name drugs.

Prices have declined for a range of reasons, in part because fewer blockbuster drugs, like the one-time Pfizer best sellers like Lipitor and Viagra, are losing their patent protection. (Prices fall more slowly immediately after patents expire, then drop precipitously after that.) Pharmacies and wholesalers have also been banding together to create giant buying groups, creating more leverage against generic drug companies.