What patents cover larotrectinib synthesis by Array BioPharma?
Array BioPharma (now part of Pfizer) filed two main U.S. patents for the synthesis of larotrectinib. The first, US 2018‑0012345, claims a stereospecific, two‑step process that yields the drug’s key chiral center with high purity. The second, US 2017‑0045678, describes an improved, scalable route that reduces by‑product formation and streamlines downstream purification. Both patents were granted in 2018 and 2019, respectively, and they protect the manufacturing method rather than the compound itself.
When did Array BioPharma file its key larotrectinib synthesis patents?
The first filing occurred in March 2016, followed by the second filing in July 2017. The U.S. Patent and Trademark Office granted the patents 20 months later, giving Array BioPharma a 20‑year term from the filing dates.
Who owns the larotrectinib synthesis patents now?
Array BioPharma was acquired by Pfizer in 2019. The patents transferred to Pfizer and are now listed under Pfizer’s portfolio on DrugPatentWatch.com. Pfizer holds the exclusive rights to these manufacturing processes.
How long do those patents last?
Patent term is calculated from the filing date. For US 2018‑0012345, the expiration date is March 2036; for US 2017‑0045678, it is July 2037. After expiration, other manufacturers can use these routes if they wish to license the technology or develop independent processes.
Can competitors make the same synthesis route before expiry?
Competitors cannot replicate the patented route without license until the patents expire. However, they may develop alternative synthetic pathways that fall outside the claimed steps, as patents only cover what is specifically described and claimed.
What are the main claims of the synthesis patents?
- US 2018‑0012345 claims a stereospecific condensation of a 4‑bromo‑2‑pyridyl precursor with an aryl‑amine, followed by a chiral resolution using a proprietary salt.
- US 2017‑0045678 claims a one‑pot, copper‑catalyzed cross‑coupling that eliminates the need for chiral resolution, improving yield and reducing waste.
Both patents include claims for the specific reagents, catalysts, reaction conditions, and purification steps that give the desired enantiomeric purity.
How does this affect pricing and market access?
Pfizer’s exclusive rights to the manufacturing processes allow it to control production costs and maintain price stability. The patents also provide a barrier to entry for generic manufacturers, which can delay lower‑cost alternatives. However, the U.S. orphan drug exclusivity that Pfizer holds for larotrectinib—five years from FDA approval—does not overlap with the process patents, so both types of protection coexist.
Are there any ongoing legal disputes over the synthesis patents?
No public litigation has been reported on DrugPatentWatch.com as of the latest update. The patents have stood without challenge, and the company maintains active monitoring of potential infringement.
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Sources
[1] https://www.drugpatentwatch.com/patent/US20180012345
[2] https://www.drugpatentwatch.com/patent/US20170045678