Second generic for prostate cancer drug Xtandi approved

Taiwan-imported Enzadex Soft Cap approved

Launch strategy targets post–compound patent expiry in June next year

Pharmaceutical companies are rapidly entering the generic market for the prostate cancer treatment ‘Xtandi (enzalutamide)’, which has a market worth approximately KRW 50 billion.

Following Alvogen Korea's initial product approval last January, Daewon Pharmaceutical has also successfully obtained approval for its generic drug. These products are expected to establish patent strategies targeting launch after the substance patent expires next June.

The Ministry of Food and Drug Safety approved Daewon Pharmaceutical's ‘Enzadex Soft Cap 40mg’ on the 23rd. This product is the second generic drug containing the active ingredient enzalutamide.

The first generic was Alvogen Korea's ‘Anamide Soft Cap 40mg’, approved last January. A common feature of both Alvogen Korea and Daewon Pharmaceutical's products is that they import the finished drug from Taiwan.

Enzadex Soft Cap is indicated for ▲ treatment of asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer (mCRPC), ▲ treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with docetaxel, ▲ treatment of patients with high-risk non-metastatic castration-resistant prostate cancer (mHSPC), ▲combination therapy with androgen deprivation therapy (ADT) for the treatment of patients with hormone-sensitive metastatic prostate cancer (mHSPC), ▲treatment of patients with high-risk hormone-sensitive non-metastatic prostate cancer (nmHSPC) who have experienced biochemical recurrence (BCR). These indications are identical to those of the original Xtandi Soft Cap 40mg.

Xtandi’s formulation patent is set to expire on June 27 next year. However, a formulation patent valid until September 11, 2033, remains a key barrier to generic entry. As a result, multiple generic manufacturers have initiated legal actions to challenge or circumvent the formulation patent.

Starting with Alvogen Korea in August, GL Pharma, Hanmi Pharmaceutical, Chong Kun Dang, JW Pharmaceutical, and Kuhnil Pharmaceutical have filed passive scope confirmation trials aimed at clearing the formulation patent hurdle.

Industry analysts suggest that if the formulation patent is successfully overcome, generics could enter the market as early as June next year.

Astellas' Xtandi competes in the first-line prostate cancer treatment market against drugs like Erleada (apalutamide, Janssen) and Zytiga (abiraterone, Janssen).

Notably, since November 2023, the patient coinsurance rate has decreased from 30% to 5%, leading to increased usage. According to the pharmaceutical market research institution IQVIA, Xtandi's sales surged from KRW 23 billion in 2019 to KRW 43.2 billion in 2023.

As the market expands, domestic pharmaceutical companies are also eagerly entering the prostate cancer treatment market. Hanmi Pharmaceutical has already moved aggressively by launching Abiteron Tab 500 mg, the first generic version of Zytiga, to secure early market share.

With Xtandi’s patent expiry approaching, many generic manufacturers are now closely monitoring the opportunity. Generic companies are simultaneously advancing patent litigation strategies and regulatory approvals, aiming for early entry in June next year.

Meanwhile, Astellas has preemptively obtained approval for Xtandi Tab, a new formulation last year, to counter the wave of emerging generic drugs. This appears to be a strategy to dilute the market impact of generic drugs by introducing a new formulation product.