(a) This section shall apply to each manufacturer of a drug product with a wholesale acquisition cost of more than forty dollars ($40) for a course of therapy as defined in subdivision (a) Health and Safety Code Section 127677.

(b) When a manufacturer proposes a wholesale acquisition cost increase that will result in a total wholesale acquisition cost increase of more than 16% above the wholesale acquisition cost of the drug product on December 31 of the calendar year three years prior to the current calendar year, the manufacturer shall provide each registered purchaser with advance notice as required by subdivisions (b) and (c) of Health and Safety Code Section 127677.

(c) Total wholesale acquisition cost increase includes the current proposed wholesale acquisition cost increase and the sum of the wholesale acquisition cost increases that occurred in the current calendar year to date and the two previous calendar years.