Xtandi generics signal June showdown as patent expiry nears

Company recently succeeded in bypassing formulation patents… Number of generic approvals rises to six

Astellas’ newly launched ‘Xtandi Tab’

GL Pharma has thrown its hat into the ring for the generic market of Astellas Pharma Korea’s blockbuster prostate cancer treatment, ‘Xtandi (enzalutamide).’ With the compound patent set to expire in June, domestic pharmaceutical companies are securing approvals one after another, and fierce competition is expected in the second half of the year to gain market leadership.

GL Pharma’s ‘Proenza’ approved… expands generic lineup

According to industry sources on the 20th, the Ministry of Food and Drug Safety (MFDS) granted marketing authorization for GL Pharma’s ‘Proenza Soft Cap 40mg.’ This product is manufactured under a contract manufacturing (CMO) arrangement with Cosmax Pharma.

With this approval, the number of domestic companies holding approvals for Xtandi generics has increased to include GL Pharma, joining existing holders Alvogen Korea (Anamide), Daewon Pharmaceutical (Enzadex), Hanall Biopharma (Enzaluta), Menarini Korea (Enzal-X), and Hanmi Pharmaceutical (Enzaron).

In particular, following Hanmi Pharmaceutical’s approval last month for the first domestically manufactured product, GL Pharma has also secured a domestically produced product, improving supply stability.

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Formulation patent through 2033 also avoided… launch barriers eliminated

The patent barriers, which had been the biggest obstacle for generic companies, have in effect all been removed. Xtandi had been protected mainly by two patents.

The compound patent (diaryl hydantoin compound) expires on June 27, 2026. Generic drugs are expected to enter the market starting at this point.

The formulation patent (enzalutamide formulation) was scheduled to expire in September 2033. However, five domestic companies, including GL Pharma, Hanmi Pharmaceutical, Chong Kun Dang, JW Pharmaceutical, and Alvogen Korea, recently succeeded in circumventing it by securing a favorable ruling after obtaining favorable decisions in passive scope confirmation trials.

As a result, domestic companies have fully secured the legal basis to launch generics early, from June 28.

Astellas’ last stand “tablet conversion”… can it defend the market?

The defense strategy of the originator company, Astellas Pharma Korea, is no less formidable. Astellas moved to defend the market by abruptly listing ‘Xtandi Tab (40 mg, 80 mg)’ for reimbursement this month, immediately before generic launch, which improves ease of administration.

Compared to the existing 40 mg soft capsule, the 40mg tablet version is about half the size, and with the addition of the 80 mg high-dose product, the daily dosage has also been reduced. Consequently, the medication burden of patients who had to take four 40 mg capsules per day is expected to be significantly eased.

The price for the 40mg product remains unchanged at KRW 14,167 per tablet, the same as the existing soft capsules, while the 80mg product is priced at KRW 21,251 per tablet. Notably, for the 80mg product, the monthly medication cost (based on 56 tablets) is approximately 25% lower than that of the existing 40mg capsules (112 capsules), which is expected to reduce the financial burden on patients.

Astellas’ strategy is to use the tablet formulation to penetrate the generic drug market, which currently consists solely of capsule formulations.

According to pharmaceutical market research firm UBIST, Xtandi recorded KRW 38 billion in sales last year, up 26% from KRW 30.2 billion the previous year. Industry attention is focused on whether Astellas can defend the market with the new tablet product.

A pharmaceutical industry source said, “With GL Pharma joining the fray, the scale of generics to be launched in line with the June compound patent expiry has grown even larger. Going forward, who secures pricing competitiveness will be one of the decisive factors.”