While domestic pharmaceutical firms voluntarily withdrew patent suits against Pfizer’s anti-arthritis therapy Xeljanz (tofacitinib), Chong Kun Dang went ahead to apply for a bioequivalence test on a generic drug of the original medicine.
Pfizer’s Xeljanz treats rheumatoid arthritis and musculoskeletal diseases, including rheumatism. The treatment drew attention as the first oral medicine for rheumatoid arthritis, which had been conventionally treated by injections such as Enbrel, Remicade, and Humira.
In the first half, sales of Xeljanz surged to 3.98 billion won ($3.51 million) from 1.69 billion won a year earlier, according to IQVIA data. The Pfizer’s drug is expected to continue robust revenue growth this year.
As the original drug is an oral medication, developing its imitation can be relatively easy for local rivals. The 5.5 trillion won market for rheumatoid arthritis is large enough for domestic players to attack Pfizer’s patent and develop a generic drug, observers said.
There are two locally-registered patents for Xeljanz – one is on the “Novel Crystal Compound” expiring on Nov. 24, 2017, and the other is on “Pyrrolo [2,3-d] Pyrimidine Compounds” expiring on Nov. 22, 2025.
Local drug companies targeted the patent on the “Novel Crystal Compound” through patent trials. Some of them successfully avoided the patent on “Pyrrolo [2,3-d] Pyrimidine Compounds” in January.
However, Jin Yang Pharmaceutical, Yungjin Pharm, and Aju Pharm announced in March, August, and September, respectively, that they would give up on the suit against Pfizer’s “Novel Crystal Compound” patent. Recently, Samil Pharmaceutical followed suit.
A series of voluntary withdrawals of the patent suits show that it was difficult for local firms to develop Xeljanz’ copy drug.
However, Chong Kun Dang recently became the first Korean company to conduct a bioequivalence test on Xeljanz’ generic copy.
Chong Kun Dang had applied to conduct a bioequivalence test on Chong Kun Dang Tofacitinib Tab. and Pfizer’s Xeljanz Tab in open, randomized, fasting, single, oral, two-group, and cross-over study.
The local company’s application is an attempt to strengthen rheumatoid arthritis area with Xeljanz’ generic, observers said.
Chong Kun Dang seemed to have paid attention to Pfizer’s ongoing trial on Xeljanz (phase-3 in active ankylosing spondylitis, phase-3/4 in ulcerative colitis), as it could expand indications depending on the results of the test.
As other domestic rivals gave up the patent suits, Chong Kun Dang will be able to obtain exclusive sales rights of a generic drug if it avoids the patent, which was also why Chong Kun Dang was going ahead with a bioequivalence test, observers said.
Even if Chong Kun Dang avoids Pfizer’s patent, however, it will be able to roll out a Xeljanz’ copy after the re-evaluation period for Xeljanz expires on April 1, 2020.
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