Mylan N.V. is waiving the exclusivity it expects for its generic version of Kaletra, which is AbbVie’s branded HIV drug being tested as a COVID-19 treatment, to allow other generic drug makers to supply the medicine sooner. It’s rare, possibly unprecedented, for a generic drug company to waive its so-called 180-day exclusivity. To encourage companies to challenge weak drug patents, patent law gives the producer of the first generic of a brand drug 180 days on the market without additional...