T 1592/12 - Plausibility and prophetic example

Key points

• In this case, the Board finds a Swiss-type for a dosage regime to be insufficiently disclosed. The claim specifies maintenance doses of an antibody every three weeks. Prior art is weekly doses, because the half-life of the antibody was considered to be around one week. The Board requires that the application makes the therapeutic effect credible for the less frequent doses. "From the general principle that the extent of the monopoly conferred by a patent should correspond to, and be justified by, the technical contribution made to the art, it follows that it is the suitability of this different administration frequency to treat breast cancer which needs to be disclosed in the patent for the requirements of sufficiency of disclosure to be met" 
• The experimental examples are based on weekly doses. The fact that the longer half-life can be inferred from the experimental data, is not relevant, because " no conclusions are drawn in the patent in suit from the data depicted in Figure 3, and no pharmacokinetic analysis of the data of Table 2 or Figure 3 is carried out. In these circumstances the board considers that the skilled person had no reason to analyse the data of example 2 with a view to reassessing the half-life of [the antibody] Herceptin**(®)." 
• The prophetic example 6 with administration every three weeks does not provide sufficiency of disclosure, because "the patent in suit neither explains why the treatment regimen will be effective nor contains data demonstrating the actual performance of the treatment regimen described." 
• " Post-published document D70 [a filing of patentee to the FDA] is considered to corroborate the board's finding in this respect. Document D70 discloses that preliminary data from 15 patients treated with Herceptin(®) administered every three weeks in combination with Taxol(®) "now indicate that the half-life Herceptin(®) is considerably longer than was originally determined" (see page 1). The document thus provides evidence that the appellant [patentee] itself, although in possession of the data of example 2 of the patent in suit and in particular of the data depicted in Figure 3 [from which the longer half-life could be inferred], had only reconsidered the half-life of Herceptin**(®) when analysing the data obtained from the clinical trial proposed in [prophetic] example 6 of the patent in suit. However, these data [of the trial] are neither contained in the patent in suit nor disclosed in the prior art. Accordingly, the [patentee's] submission that the notional skilled person reading the patent in suit would have realised from the data in its example 2 that the half-life of Herceptin**(®) was considerably longer is also contradicted by the evidence provided in document D70." 

EPO T 1592/12 -  link

Sufficiency of disclosure - claim 1

14. Independent claim 1 is formulated as a "Swiss-type" claim and relates to the use of the anti-ErbB2 antibody huMab 4D5-8, commonly known as trastuzumab (Herceptin**(®)), for treating a human patient diagnosed with breast cancer, whereby the antibody is administered at an initial dose of 8 mg/kg followed by maintenance doses of 6 mg/kg every three weeks (in brief 8/6/3).

15. Sufficiency of disclosure requires that the European patent application or European patent disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art

(Articles 83 and 100(b) EPC). According to established case law of the boards of appeal (see decision T 609/02 of 27 October 2004, point 9 of the reasons) where a therapeutic application is claimed in the form of a "Swiss-type" claim, attaining the claimed therapeutic effect is a functional technical feature of the claim. As a consequence, under Article 83 EPC, unless this is already known to the skilled person at the priority date, the application must disclose the suitability of the product to be manufactured for the claimed therapeutic application. In this context, post-published evidence may be taken into account, but only to back up the findings in the patent application and not to establish sufficiency of disclosure on their own.

16. The principles established in decision T 609/02, supra, in relation to sufficiency of disclosure of a second medical use claim do not relate only to the factual situation in that specific case, but are accepted to be generally applicable to such claims (see Case Law of the Boards of Appeal of the EPO, 8th edition 2016, section II.C.6.2 and decisions referred to therein).

17. The appellant's argument that for compliance with the requirement of sufficiency of disclosure it suffices that the skilled person can carry out the claimed dosage regimen thus fails.

18. The appellant's further argument that for such compliance it suffices that the suitability of the Herceptin**(®) antibody for treating breast cancer characterised by overexpressing ErbB2 was well known in the art also fails, for the following reasons.

19. In the present case, the technical contribution does not reside in the provision of Herceptin**(®) for treating breast cancer. Indeed, the parties agree that, at the effective date of the patent, Herceptin**(®) was well known to be suitable to treat breast cancer - if given weekly, and more specifically with a dosage regimen of a starting dose of 4 mg/kg followed by weekly doses of

2 mg/kg (in brief 4/2/1).

20. However, the claimed treatment regimen differs from the known treatment regimen in the administration frequency of Herceptin**(®), i.e. every three weeks instead of weekly. From the general principle that the extent of the monopoly conferred by a patent should correspond to, and be justified by, the technical contribution made to the art, it follows that it is the suitability of this different administration frequency to treat breast cancer which needs to be disclosed in the patent for the requirements of sufficiency of disclosure to be met (see also decision T 609/02, supra, reasons,

point 8).

21. Accordingly, since in the present case the pharmaceutical usefulness of Herceptin**(®) for treating breast cancer is undisputed, decisions T 433/05 of 14 June 2007 and T 601/05 of 2 December 2009, which held that an active agent's pharmaceutical usefulness may be evident from common general knowledge, do not assist the appellant's case.

22. According to established case law, a sufficient disclosure must be made at the effective date of the patent, on the basis of the information in the patent together with the common general knowledge then available to the skilled person (cf. decision T 609/02, supra, reasons, point 8).

23. The appellant did not dispute that the following facts summarise the common general knowledge of the skilled person before the first priority date of the patent in suit. A serum trough concentration of at least 10 to 20 myg/ml Herceptin**(®)is necessary for therapeutic efficacy in the treatment of breast cancer; the appropriate dosing interval suitable for achieving accumulation of the antibody up to the targeted serum trough concentration should not be substantially longer than the half-life of the corresponding antibody because otherwise no accumulation to the targeted serum trough concentration is achieved; and the half-life of Herceptin**(®)is around one week (see also document D2, page 309, left hand column and right hand column, paragraph bridging pages 312 and 313; document D4, page 2660, left hand column, third paragraph, Table 6; and document D9, page 738, right hand column, 4th paragraph and page 739, right hand column, second paragraph).

24. The patent in suit concerns the treatment of human patients diagnosed with cancer overexpressing ErbB2 wherein the anti-ErbB2 antibody is administered by front loading which has the advantage of increased efficacy by reaching a target serum drug concentration early in treatment (see paragraphs [0001], [0016] and [0088]). The patent in suit discloses infrequent dosing of anti-ErBB2 antibodies (see paragraph [0001]) but also that the initial dose is separated in time from the first subsequent dose "most preferably 1 week or less" (see paragraphs [0016] and [0214]) while paragraph [0028] discloses that the first dose and subsequent doses are separated by about two weeks to about two months. The patent furthermore sets out numerous permutations of possible doses and dosage intervals including the claimed regimen (see paragraphs [0017] to [0024] and paragraphs [0166] to [0172]).

25. Example 1 of the patent in suit provides details for the preparation of the Herceptin**(®) antibody and for combination therapy with chemotherapy. On day 0, patients received a 4 mg/kg dose of Herceptin**(®),**()followed by weekly administration of 2 mg/kg antibody (in brief 4/2/1), while chemotherapy was started 24 hours after the initial dose of Herceptin**(®). The administration frequency of Herceptin**(®)is thus the same as in the prior art, i.e. weekly. **()

26. Also example 2 relates to the 4/2/1 dosing regimen known in the prior art. Table 2 reports Herceptin**(®)anti-ErbB2 antibody trough and peak serum concentrations for the first 8 weeks of treatment, while Figure 3 is a graph of Herceptin**(®)trough serum concentration from week 2 through week 36 of treatment. The patent in suit states with reference to Figure 3 that "trough serum concentrations tended to increase through week 12 and tended to plateau after that time" (see paragraph [0198]). The board notes however that no importance is attached to the data shown in Figure 3, nor are these data combined with those of Table 2.

27. Example 2 mentions one alternative dosing regimen wherein an initial dose of 8 mg/kg is followed by weekly administration of 4 mg/kg Herceptin**(®)(in brief 8/4/1), and notes a significant difference between the Herceptin**(®)trough serum concentration in the responders and non-responders. The patent in suit then concludes that the data disclosed in example 2 indicate "that front loading of antibody, such that a target serum concentration is reached more quickly, may be associated with improved outcomes" (see paragraphs [0201] and [0203]).

28. The board concludes from the above that the skilled person, having read the general description of the patent in suit which emphasises weekly administration as most preferred and having studied examples 1 and 2 which likewise apply weekly administration, would rely on Herceptin**(®)'s known half-life of one week to assess the suitability of the claimed dosing regimen. The skilled person would thus have serious doubts that three-weekly administration of Herceptin**(®)would suffice to maintain the serum trough concentration of Herceptin**(®)required for effective treatment of breast cancer (see point 23).**()Consequently, the suitability of the claimed dosing regimen for the treatment of breast cancer cannot be considered to have been disclosed.

29. The appellant argued that the patent in suit repeatedly emphasised a more infrequent dosing than that known from the prior art. The skilled person would therefore study the data provided in example 2 and understand therefrom that the half-life of the huMab 4D5-8 antibody was sufficiently long for administration once every three weeks.

30. The board notes however that the half-life of Herceptin**(®) is not mentioned in example 2 or anywhere else in the patent. The most preferred dosing frequency in the patent in suit is disclosed to be weekly, and also the administration frequency of both trials in example 2 is weekly. Weekly administration is in line with a half-life of one week, i.e. the half-life of Herceptin**(®) the skilled person was familiar with (see point 23 above).

31. The board further notes that the sole conclusion drawn in the patent in suit as regards example 2 concerns the beneficial effect of front loading in the context of weekly dosing of Herceptin**(®). However, no conclusions are drawn in the patent in suit from the data depicted in Figure 3, and no pharmacokinetic analysis of the data of Table 2 or Figure 3 is carried out. In these circumstances the board considers that the skilled person had no reason to analyse the data of example 2 with a view to reassessing the half-life of Herceptin**(®).

32. Therefore, the question whether the skilled person would have recognised that the data in Table 2 and Figure 3 needed to be combined, and a pharmacokinetic model different from the one used in the prior art was required to actually arrive at a half-life of 28 days does not arise. Accordingly, and for the same reasons, declarations D39, D40 and D57 - which merely confirm that an analysis of the data in example 2 yields a half-life of 28 days - do not assist the appellant's case.

33. In view of the above considerations the appellant's main argument fails.

34. The appellant's further argument was based on example 6 of the patent in suit. This is a prophetic example which discloses that the recommended dose of Herceptin**(®) at the relevant date was 2 mg/kg once weekly and proposes that "Patients will be administered HERCEPTIN® every three weeks instead of weekly, along with paclitaxel (175mg/m**(2) every three weeks). Simulation of the proposed treatment regimen suggests that the trough serum concentrations will be 17 mcg/ml, in the range (10-20 mcg/ml) of the targeted trough serum concentrations from previous HERCEPTIN® IV clinical trials. After the first 12 patients the PK parameters will be assessed, if exposure is felt inadequate, then the dose will be increased to 8 mg/kg every three weeks for the remaining 12 patients" (see paragraph [0227]). The example concludes by stating that "it is believed that the above treatment regimen will be effective in treating metastatic breast cancer, despite the infrequency with which HERCEPTIN® is administered to the patient" (see paragraph [0233]).

35. The board notes that the patent in suit does not disclose the nature of the described "simulation of the proposed treatment regimen". Moreover, the patent in suit neither explains why the treatment regimen will be effective nor contains data demonstrating the actual performance of the treatment regimen described.

36. The board further notes that the skilled person reading example 6 is however aware that the half-life of Herceptin**(® )is assumed in the art to be around one week, and thus too short to maintain an effective trough serum concentration when Herceptin**(® )is administered once every three weeks (see point 23 above).

37. The board concludes from the above that the skilled person would thus have serious doubts that three-weekly administration of Herceptin**(®)would suffice to maintain the serum trough concentration of Herceptin**(®)required for effective treatment of breast cancer (see point 23). This has the consequence that the suitability of the claimed dosing regimen for the treatment of breast cancer cannot be considered to have been disclosed by example 6 either.

38. The appellant submitted that "the skilled person who wanted to carry out the claimed invention would look for the basis for the inventors' stated belief that the treatment regimen will be effective [note by the board: point 34 above] which would have motivated analysis of the data of example 2 with consequent appreciation of the longer half-life."

39. The board notes however in this context that example 6 does not explain how the simulation of the proposed treatment regimen was done or that it was based on the data of example 2. Also, the proposed treatment regimen of example 6 is a combination therapy of Herceptin**(®)with paclitaxel administered every three weeks, while example 2 relates to a monotherapy with Herceptin**(®)which is administered weekly. Thus, example 2 relates not only to a different dosage regimen but to a different treatment regimen. In the board's judgement, the skilled person thus had no reason to turn to example 2 or to analyse the data of example 2 when faced with the treatment proposed in example 6.

40. Post-published document D70 is considered to corroborate the board's finding in this respect. Document D70 discloses that preliminary data from 15 patients treated with Herceptin**(®) administered every three weeks in combination with Taxol**(®) "now indicate that the half-life Herceptin**(®) is considerably longer than was originally determined" (see page 1). The document thus provides evidence that the appellant itself, although in possession of the data of example 2 of the patent in suit and in particular of the data depicted in Figure 3, had only reconsidered the half-life of Herceptin**(®) when analysing the data obtained from the clinical trial proposed in example 6 of the patent in suit. However, these data are neither contained in the patent in suit nor disclosed in the prior art. Accordingly, the appellant's submission that the notional skilled person reading the patent in suit would have realised from the data in its example 2 that the half-life of Herceptin**(®) was considerably longer is also contradicted by the evidence provided in document D70.

41. In conclusion, the board, having regard to the facts and arguments presented to it, decides that the contested patent does not disclose the suitability of Herceptin**(®)for the treatment of breast cancer with the claimed dosage regimen.

42. Under these circumstances, the appellant cannot rely on post-filed evidence such as document D54 (see point 15 above). In this context the board notes that in T 157/03 of 4 January 2005 the deciding board accepted that post-published documents could be used as evidence as to whether the invention was indeed reproducible without undue burden at the relevant filing date (see reasons, point 9). However, as set out above (see points 15 and 16), the established case law followed by this board requires the suitability of the claimed dosage regimen to be disclosed at the effective date of the patent. Accordingly, the appellant's reliance on decision T 157/03, supra, cannot lead to a different conclusion as regards sufficiency of disclosure.

43. The decision of the opposition division as regards insufficiency of disclosure (Article 100(b) EPC) of the subject-matter of claim 1 was correct.

Order

For these reasons it is decided that:

The appeal is dismissed.