Paclitaxel SPC bound to fail

Background

The period that elapses between a patent being granted for a new medicinal product and a marketing authorisation being obtained for the product is often too short to allow a patentee to cover their investment. Supplementary protection certificates (SPCs) are intended to compensate patentees for the investment necessary to place a new medicinal product on the market.

Abraxis BioScience LLC had obtained a patent (EP 0961612) entitled “protein stabilized pharmacologically active agents and their use” covering their product Abraxane^TM, which comprises paclitaxel formulated as albumin bound nanoparticles (referred to as “nab-paclitaxel”). The patent was due to expire in September 2017 so Abraxis applied for an SPC at the UK IPO to extend patent protection of their product in the UK.

SPCs are available throughout Europe and, at present, must be obtained on a country-by-country basis. To obtain granted SPCs certain requirements must be met, including (in accordance with Article 3 of the SPC Regulation):

(a) the product must be protected by a patent;
(b) a valid marketing authorisation has been granted;
(c) the product has not already been the subject of an SPC;
(d) the authorisation referred to in point (b) is the first authorisation to place the product on the market as a medicinal product.

The product is defined as “the active ingredient or combination of active ingredients of a medicinal product” in Article 1(b) of the SPC Regulation.

SPC applications are formally examined in a similar manner to patent applications.  During the examination process, the applicant (or their representative) often has to satisfy the examiner that the patented product is the same product as the authorised product and/or that any previous marketing authorisations are not relevant to the product. In this case, the examination focussed on whether previously obtained marketing authorisations were relevant to Abraxis’ product.

Summary

The UK IPO examiner refused Abraxis’ SPC application on the basis that paclitaxel was the sole active ingredient in the product and paclitaxel had previously received marketing authorisations in the EU. Hence the examiner believed that the previous marketing authorisations for paclitaxel prevented an SPC being granted for Abraxis’ product. Abraxis appealed the examiner’s decision submitting that nab-paclitaxel was a new sole active ingredient and that, therefore, the previous marketing authorisations for paclitaxel were irrelevant to their SPC application.

Abraxis made numerous detailed arguments in support of the assertion that nab-paclitaxel was a new sole active ingredient during the hearing at the UKIPO. In particular, it was asserted that the binding between paclitaxel and albumin created a new sole active ingredient. However, although the UKIPO hearing officer accepted that albumin and paclitaxel are tightly bound together in nab-paclitaxel nanoparticles, he did not consider that the physical-chemical properties of the particles created a new sole active ingredient. Abraxis also relied upon the fact that nab-paclitaxel is safer and more effective that paclitaxel because it is less likely to result in allergic side effects than paclitaxel and because it can be used to treat cancers that paclitaxel cannot be used to treat. The hearing officer accepted that the pharmacological activity of nab-paclitaxel is distinct from that of paclitaxel and acknowledged the data demonstrating the effects of nab-paclitaxel on cancer cells and on the tumour microenvironment. However, the hearing officer did not consider that this necessarily proved that nab-paclitaxel was a new sole active ingredient.

For the sake of completeness, the hearing officer also considered whether nab-paclitaxel should be viewed as a combination of active ingredients. For nab-paclitaxel to be viewed as a combination of active ingredients it would need to be established that both the paclitaxel and the albumin had a therapeutic effect. However, the examiner concluded that the albumin behaves as a carrier in nab-paclitaxel and so the albumin is not an active ingredient.

Despite the detailed arguments submitted by Abraxis, the hearing officer refused the application on the basis that the combination of paclitaxel and albumin in nab-paclitaxel did not create a new sole active ingredient and nab-paclitaxel did not comprise a combination of active ingredients since albumin did not have a therapeutic effect of its own.

Abraxis have since appealed the refusal by the UK IPO and submitted that questions regarding the interpretation of Articles 1(b) and 3(d) of the SPC Regulation (see “Background” above) needed to be referred to the CJEU. When conducting the appeal, Mr Justice Arnold reviewed case law relevant to both these Articles and concluded that the law was clear regarding Article 1(b), but not Article 3(d). Therefore, Mr Justice Arnold has referred the following question to the CJEU:

“Is Article 3(d) of the SPC Regulation to be interpreted as permitting the grant of an SPC where the marketing authorisation referred to in Article 3(b) is the first authorisation within the scope of the basic patent to place the product on the market as a medicinal product and where the product is a new formulation of an old active ingredient?”

If the answer is no (as Mr Justice Arnold has suggested it should be), then Abraxis will not be granted an SPC for nab-paclitaxel.

Conclusion

SPC applications for products comprising a known active ingredient in combination with another ingredient may not be granted. Whether such applications are granted is likely to depend on whether the combination creates a new sole active ingredient and whether both ingredients have a therapeutic effect. The CJEU’s response to the question referred by Mr Justice Arnold should help clarify the requirements for grant of an SPC.

---

Category: Latest Insights | Author: Marianne Privett | Published: May 2017 | Read more