Kadcyla is a biologic drug used in the treatment of certain types of breast cancer. To determine its market exclusivity timeline, we can refer to the provided sources.

According to the first source, DrugPatentWatch, Kadcyla's composition of matter patent is set to expire on May 18, 2020. This patent, listed as US 8,283,364, provides exclusivity for the unique chemical structure of the drug. However, it's important to note that this source does not provide information on any additional patents or exclusivity rights that may apply to Kadcyla.

The second source, FiercePharma, lists Kadcyla as one of the top 15 blockbuster patent expirations in the coming decade. While it does not provide specific dates, it suggests that Kadcyla's patent exclusivity is set to expire soon.

To get a more comprehensive understanding of Kadcyla's market exclusivity, we can turn to the third source, the FDA's Purple Book. This resource provides information on licensed biological products, reference product exclusivity, and biosimilarity. However, upon reviewing the Purple Book, it appears that Kadcyla is not specifically listed.

Based on the information available from the sources, it can be concluded that Kadcyla's composition of matter patent has expired on May 18, 2020 [1]. However, it is unclear if there are any additional patents or exclusivity rights that may apply to the drug. Further research or consulting additional sources may be necessary to obtain a complete market exclusivity timeline for Kadcyla.

Sources:
[1] DrugPatentWatch - Kadcyla: https://www.drugpatentwatch.com/p/biologics/tradename/KADCYLA
[2] FiercePharma - Top 15 blockbuster patent expirations: https://www.fiercepharma.com/special-report/top-15-blockbuster-patent-expirations-coming-decade
[3] FDA - Purple Book: https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/purple-book-lists-licensed-biological-products-reference-product-exclusivity-and-biosimilarity-or