what is the meaning of "Wholesale Acquisition Cost (WAC)" as used in
the phrase:  " XXX has priced the product at a 10% discount as
compared to the Wholesale Acquisition Cost (WAC) for the most widely
prescribed extended release OAB branded products, specifically product
Z and Y"

Hi

Thanks for your question. Having worked around health service
pharmacies, I knew the answer to this one :)

The WAC or Wholesale Acquisition Cost is the list price for
wholesalers, distributors and other direct accounts before any
rebates, discounts, allowances or other price concessions that might
be offered by the supplier of the product

For example, a drugs wholesaler (XXX) might quote a hospital a figure
of 10% below the WAC if they buy products X and Y in bulk, whereas
they would have to pay the full WAC otherwise. The WAC is what the
wholesaler buys the drugs for from the manufacturer.

Here's a quote from an OXERA report on the US drugs industry that
clarifies things ( http://www.doh.gov.uk/generics/oxera_report_a7.htm
)

"In the USA, the wholesaler industry is a concentrated market
dominated by five firms. Wholesalers act as distributors, buying
pharmaceuticals from manufacturers at the average manufacturer price,
(which is equal to the WHOLESALE ACQUISITION COST), and then selling
them on to pharmacies using a ‘cost-plus’ approach (plus a mark-up
percentage) or a ‘list-less’ approach (less a discount percentage).
During the last decade, wholesalers experienced declining gross
margins—the difference between the WHOLESALE ACQUISITION COST they pay
the manufacturer and the price they sell to pharmacies—declining net
profits and declining operating expenses

Hope that helps

willie-ga

Google serch used
"wholesale acquisition cost" definition

Thank you! You worked fast and precise. 
Regards, Tom.