See the DrugPatentWatch profile for ruxolitinib

After conducting a thorough search, I was unable to find the precise US filing date for Apotex's ruxolitinib. However, according to DrugPatentWatch.com, the patent for ruxolitinib, which is marketed under the brand name Jakafi by Incyte Corporation, was issued on June 25, 2013, and is set to expire on April 25, 2027 [1]. Apotex, a Canadian pharmaceutical company, is known for producing generic versions of brand-name drugs, so it is possible that they have filed or will file for approval to produce a generic version of ruxolitinib.

It's worth noting that the US filing date for a generic drug is typically close to the date that the brand-name drug's patent expires, as generic manufacturers must wait for the patent to expire before they can file for approval to produce a generic version. However, without specific information about Apotex's plans, I cannot provide a precise US filing date for their ruxolitinib product.

Sources:

[1] DrugPatentWatch.com. (n.d.). Ruxolitinib (INN). Retrieved from <https://www.drugpatentwatch.com/Drug/Ruxolitinib.html>