Generic drug maker reverses unfavorable judgment after expiration of patent term

AstraZeneca is the owner of Taiwanese patent I238720 entitled “Pharmaceutical composition for use in the treatment of heterozygous familial hypercholesterolemia.” AstraZeneca manufactures Rosuvastatin under the famous trade name Crestor. Sold in 20mg and 10mg tablets, Crestor is a statin medication to treat cardiovascular disorders such as dyslipidaemia and hypercholesterolaemia by working as a certain reductase’s inhibitor in order to reduce the production of low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL). After the pharmaceutical patent linkage system was instituted into law, AstraZeneca listed the ‘720 patent to declare it associated with Crestor 10mg and 20mg tablets.

TSH Biopharm (“TSH”) of Taiwan developed Cretrol tablets, a medication that contains Rosuvastatin calcium and Ezetimibe as active ingredients for curing primary hypercholesterolemia and dyslipidaemia. In October 2019, to apply for regulatory approval, TSH declared that Cretrol did not infringe the ‘720 patent pursuant to the Pharmaceutical Act and relevant regulations.

In response to TSH’s declaration, AstraZeneca filed an infringement suit in an attempt to prevent the manufacture, use, sale, offer for sale, or import activities relating to Cretrol. AstraZeneca asserted that, by treating primary hypercholesterolemia (PH), TSH’s Cretrol also treats its sub-form - the heterozygous familial hypercholesterolemia (HeFH) - and therefore infringes the ‘720 patent. The hierarchical relationships of PH, HeFH, and other relevant diseases are illustrated below.

Tsai, Lee & Chen was retained to defend TSH.

As the lawsuit was ongoing, TSH applied for revision of therapeutic indications on the product label. Specifically, the intended original use of Cretrol was written to treat “primary hypercholesterolemia.” But it later added an exclusion to say “primary hypercholesterolemia (excluding the heterozygous familial type).” In other words, the drug authority approved the indications on the product label to become essentially non-familial hypercholesterolemia (Non-FH) and homozygous familial hypercholesterolemia (HoFH) but not HeFH.

TSH as the defendant in its arguments stressed that the mere act of applying for marketing approval of a drug should not constitute an infringement by default. However, the patent linkage system creates a legal fiction to regard an application for marketing approval a quasi-infringement. Meanwhile, the system creates an exception available for the applicant to elude fictional infringement. Article 48-20(2)(2) of the Pharmaceutical Act particularly prescribes that “[in the event where] the applicant for a generic drug’s marketing approval exclude a therapeutic indication corresponding to a patent claim of pharmaceutical use and then declare non-infringement,” the remaining rules regarding a suspension for granting the generic marketing approval and a sales exclusivity shall not apply. Indeed, according to its legislative background, Article 48-20 was stipulated to offer a generic drug a chance to avoid the risks of infringement by way of excluding a certain number of therapeutic indications that are overlapped with those of a patented drug. That is, “carve-out” is a permissible practice to prevent infringement.

Moreover, the ‘720 patent’s claims were “product-by-process” claims. Based on the patent examination guidelines prior to 2013, the features of use were limitations to the claimed scope. The enforceable scope of patent right is to be restricted to only the pharmaceutical use as claimed. Claim 1 directs to a “use of [Rosuvastatin] or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for use in the treatment of a patient suffering from heterozygous familial hypercholesterolemia.” The “treatment of heterozygous familial hypercholesterolemia (HeFH)” was a limiting feature suggesting that only another drug that cures HeFH would read on Claim 1. However, in the present case, there was no drug product that actually went into production by the defendant TSH to begin with. Moreover, as explained above, the product label as revised specifically carved out the therapeutic indication of HeFH. Hence, TSH’s application for its marketing approval should not be infringing.

Regrettably, in the court’s approach to the case, it went beyond what the revised product label read and studied rather scientifically whether the Cretrol’s combination of ingredients - namely Rosuvastatin calcium and Ezetimibe - would treat HeFH despite the fact that Cretrol was not even produced yet. The court concluded the answer to be “yes” and hence ruled that this hypothetical product Cretrol infringing on Claims 1, 5, and 8 of the ’720 patent. The trial judgment was made on October 26, 2021.[1] The defendant TSH quickly appealed under the advice of Tsai, Lee & Chen who continued to be the sole counsel for the case in the second instance.

During the pendency of the appellate level, the ‘720 patent became expired on November 20 of 2021, which was before the close of oral argument proceedings. The appellate court did not delve into the substantive issues such as the scope of claimed patent rights and the therapeutic indications on the product labels. Instead, the court only focused on the lapse of patent term. Notwithstanding the appellant’s necessity of legal protection existed in the first instance, the court shall rule to dismiss the case if such necessity becomes extinguished before the oral argument finishes, the court cited.[2] The case went moot. Thus the court held dismissal of the case.[3] The entire trial judgment was vacated. The legal status of both parties returns to the state of no infringement.

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