Generic market for anti-cancer drug Xtandi heats up

As the substance patent nears expiration, applications for film-coated tablets follow soft capsules

Independent 40mg, 80mg, and 160mg lineups set, targeting first generic exclusivity…major battle anticipated

Original Xtandi Tab

The generic market for Xtandi (enzalutamide, Astellas), a blockbuster prostate cancer treatment, is in turmoil.

With the expiration of the substance patent approaching this June and approvals for soft capsule generics coming one after another, latecomers are now setting their sights squarely on the ‘tablet’ market—the original manufacturer’s latest strategic weapon— rapidly expanding the competitive battlefield.

According to industry sources, on April 24, applications for approval of three film-coated tablet strengths of enzalutamide (40mg, 80mg, and 160mg) were simultaneously submitted to the Ministry of Food and Drug Safety. Industry attention is focused on these applications because they aim to secure ‘first generic exclusivity,’ considered the key to early market dominance.

From capsules to tablets…follow-up approvals accelerate after breaking the 2033 barrier

Originally, the Xtandi generic market had been developing primarily around soft capsule formulations timed with the expiration of the substance patent on June 27. Major pharmaceutical companies, including Alvogen Korea, Daewon Pharmaceutical, Hanmi Pharmaceutical, GL Pharma, and Dongkook Pharmaceutical, have already obtained approvals for soft capsule generics and are preparing to launch.

In response, original manufacturer Astellas Pharma Korea introduced ‘Xtandi Tab’ (40mg and 80mg) with improved dosing convenience and completed reimbursement listing last April. This was part of a defensive strategy to shift the market’s center of gravity toward tablets and fend off the generic competition. This was because the tablet formulation was protected by a separate composition patent valid until September 2033.

However, the defensive line collapsed as domestic pharmaceutical companies successively succeeded in circumventing this 2033 formulation patent through a series of negative scope confirmation trials. The latest film-coated tablet generic applications are therefore interpreted as the first step toward realizing a ‘dual competition’ structure between dosage forms after neutralizing the patent barrier.

Addition of a 160mg high-dose option… Aiming for exclusivity through first generic approval rights

A notable feature of the film-coated tablet lineup applied for this time is the inclusion of a 160mg high-dose product, which is not available in the original Xtandi Tab lineup (40mg, 80mg).

Currently, patients face the inconvenience of having to take four 40mg soft capsules at once each day. In response to the original manufacturer introducing an 80mg tablet form to reduce the number of pills taken to two, the generic manufacturer has launched a counterattack by developing a 160mg ultra-high-dose formulation that requires taking “just one pill a day.” This is a strategy to surpass the original in terms of convenience.

Furthermore, if these companies secure first generic exclusivity based on the latest applications, they will gain the privilege of blocking other tablet generics from entering the market for a certain period while competing exclusively against the original product.

A pharmaceutical industry official predicted, “If the ‘first war’ takes place in June when soft capsule generics flood the market immediately after the substance patent expires, then approvals and reimbursement listings for tablet generics pursuing first generic exclusivity will ignite the ‘second war’ in the second half of the year.”

As a direct confrontation approaches between the original company’s market-defense strategy through tablet conversion and domestic pharmaceutical firms seeking early dominance of the tablet market through patent circumvention and independent high-dose lineups, the industry’s attention is focused on who will take the lead in the enzalutamide market. Xtandi recorded domestic sales of KRW 38 billion last year, according to UBIST data.