Sun Pharma surprised the pharma industry when its prostate cancer treatment Yonsa was approved, putting the drug, which treats metastatic-castration-resistant prostate cancer, into direct competition with Johnson & Johnson’s Zytiga.
Although the approval was unexpected, analysts from Credit Suisse expect minimal impact on the Johnson & Johnson drug’s sales. Zytiga went off-patent in December 2016, but J&J hadn’t faced any competition due to other method-of-use patents. Sun Pharma got around those patents by pairing Yonsa with a different drug.
In the first quarter, Zytiga saw $407 million in U.S. sales, a 74.7% increase over 2017. Analysts already expected generic competition for Zytiga by the fourth quarter of 2018, which would drop its sales numbers. However, competition from a new branded drug is expected to be minimal, according to analysts.
The issues holding Yonsa back are that it is branded competition rather than generic and it has a narrower indication. Sun Pharma will need to either convince doctors to switch their patients off of Zytiga or convince payors to force patients to switch in order to make a bigger market impact, according to analysts.
Sun Pharma acquired Yonsa from Churchill Pharmaceuticals. In the U.S., Sun had $2.1 billion in sales in 2017, though its U.S. sales have been dropping since 2015.