The number of companies challenging the patent of Pfizer’s breast cancer treatment ‘Ibrance (palbociclib)’ has increased to 5.

According to the pharmaceutical industry, Boryung Pharmaceutical, Shinpoong Pharm, Daewoong Pharmaceutical, and Samyang Holdings had filed a series of claims to confirm the passive scope of rights on Ibrance’s crystalline form patent.

Kwang Dong Pharmaceutical had been the first to challenge the patent on the 3rd of this month. With the additions, a total of 5 companies will be attempting to avoid the crystalline form patent of Ibrance. In the case of Kwang Dong Pharmaceutical, the company had also received approval for a bioequivalence test to develop a gen