DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
Status of the Claims
Pursuant to the amendment dated 10/24/2025, claims 10-15 have been cancelled and new claim 16 has been added. Claims 1-8 were cancelled previously.
Claims 9-15 are pending and under current examination.
All rejections not reiterated have been maintained.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
(a) A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under pre-AIA 35 U.S.C. 103(a) are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims under pre-AIA 35 U.S.C. 103(a), the examiner presumes that the subject matter of the various claims was commonly owned at the time any inventions covered therein were made absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and invention dates of each claim that was not commonly owned at the time a later invention was made in order for the examiner to consider the applicability of pre-AIA 35 U.S.C. 103(c) and potential pre-AIA 35 U.S.C. 102(e), (f) or (g) prior art under pre-AIA 35 U.S.C. 103(a).
Claims 9 and 16 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Jahagirdar et al. (EP2011486A1; publication date 01/07/2009; cited in the IDS filed 03/14/2025).
With regard to claim 9, Jahagirdar discloses a bilayer tablet wherein the tablet contains a first layer comprising rifaximin, HPMC (i.e. Hypromellose), diluents selected from microcrystalline cellulose or mannitol, colloidal silicon dioxide, and magnesium stearate and contains a second layer having HPMC (i.e. Hypromellose), polyoxyethylene, colloidal silicon dioxide, and magnesium stearate. The claims are considered obvious under 35 USC 103(a) because the composition is not described as containing both microcrystalline cellulose and mannitol; however, it would have been prima facie obvious to combine these two substances in the tablet because they are both disclosed to be diluents. See MPEP 2144.06(I): "It is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose.... [T]he idea of combining them flows logically from their having been individually taught in the prior art." In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980).
Many of the examples on pages 8-20 are tablets having first and second layers containing the substances noted above. The second layer consists of HPMC, PEO colloidal silicon dioxide, and magnesium stearate, as required by instant claim 9. The first layer typically contains just one substance that has been excluded by the transitional phrase “consisting of” recited in instant claim 9. Example 2 is reproduced below:
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Thus, the composition of example 2 contains all of the ingredients required by the instant claims and also contains PEO in the first layer, which is excluded by the transitional phrase “consisting of” preceding the listing of substances that may be present in the first layer. However, replacing PEO with additional HPMC (i.e. Hypromellose) would have been prima facie obvious to one of ordinary skill as of the instant effective filing date: Jahagirdar discloses that polyethylene oxide can serve as a bioadhesive polymer (0032) or as a binder (0046). In both locations, Jahagirdar also discloses that HPMC was another polymer known to serve these purposes. It would have been prima facie obvious to replace PEO in layer 1 of example 2 with HPMC because these substances were known to serve the same purpose at the time the instant invention was filed (see MPEP 2144.06).
Claim 9 also requires the PEO to be present in a 9:2 weight ratio to colloidal silicon dioxide and the Hypromellose to be in a 9:2 weight ratio to the magnesium stearate in the second layer of the tablet. In example 2, the ratio of HPMC (Hypromellose) to magnesium stearate is 5:1, i.e. 10:2, which falls close to the required ratio. The ratio of PEO to colloidal silicon dioxide is 3.5:1, i.e. a different ratio than required by the instant claims. However, there is a range of ratios disclosed in the examples implying that the amount of these substances can be varied to achieve a target drug release profile, and no limit is stated in the broader disclosure on amounts of HPMC, colloidal silicon dioxide, PEO, or magnesium stearate. Moreover, Jahagirdar describes the effects each of these substances has on the composition (bioadhesive, binder, lubricant, and glidant; 0032, 0046, 0048, 0049). It would have been merely optimization for one of ordinary skill to adjust the quantities of ingredients disclosed by Jahagirdar to provide their disclosed effect to the composition. See MPEP 2144.05(II)(A): Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Instant claim 16 recites specific quantities of each ingredient in the second layer. Analogously to the statement above regarding claim 9, the examiner does not consider the amounts of each substance to patentably define over the cited prior art because such falls within the narrow scope of Jahagirdar’s disclosures.
The examiner notes that the instant claims recite “a solid dispersion of rifaximin”. Page 6 of the specification states “The term ‘solid dispersion’ means the finely dispersed distribution of one or more components, e.g. an active substance like rifaximin, in an inert solid or semi-solid carrier which increases wettability and/ or solubility; it also embraces semi-solid dispersions. The active substance may be present in molecular dispersed form, i.e. as a solid solution, in fine crystalline dispersed form, in a glassy amorphous phase or dispersed as a fine amorphous powder. Eutectic mixtures, i.e. crystalline structures of active substances and carriers are also encompassed in the definition of ‘solid dispersions’.” Therefore the examiner considers the phrase “a solid dispersion of rifaximin to read on example 1 of Jahagirdar because the rifaximin is incorporated into the first layer by sifting/dry blending with the other ingredients followed by compression tableting. This would result in a finely dispersed distribution of the active component, rifaximin, in the inert solid carrier.
Response to Arguments
Applicant's arguments filed 10/24/2025 have been fully considered but they are not persuasive. On pages 1-2, Applicant asserts that Jaagirdar does not disclose or teach the instant invention as claimed in the amendments filed 10/24/2025. This argument is not persuasive because the instant invention, as claimed, is an obvious variant of Jahagirdar, as detailed in the rejection above.
Conclusion
No claims are allowed.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KATHERINE PEEBLES whose telephone number is (571)272-6247. The examiner can normally be reached Monday through Friday: 9 am to 3 pm.
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/KATHERINE PEEBLES/ Primary Examiner, Art Unit 1617