DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on May 21, 2026 has been entered.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-12 and 26 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation "the z end groups" in the final line. There is insufficient antecedent basis for this limitation in the claim. In particular, the variable z in claim 1 is defined as an integer rather than an end group. Claims 2-12 and 26 depend from claim 1 and are therefore similarly indefinite.
The claimed formula does include end groups R3. For the purpose of examination on the merits, claim 1 and its dependent claims will be interpreted as requiring from 2 to 4 R3 groups to be hydrophobic end groups. An amendment to this effect would be sufficient to overcome the rejection under 35 U.S.C. 112(b).
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over Zhao et al. (US 2013/0144014; cited in prior Office action).
Regarding Claims 1-3 and 5-10, Zhao teaches multi-arm block copolymers comprising a central core molecule, such as a polyol residue, and at least three copolymer. Each copolymer arm comprises an inner hydrophobic polymer segment covalently attached to the central core molecule and an outer hydrophilic segment covalently attached to the hydrophobic polymer segment (Abstract).
One example of Zhao’s copolymer is illustrated in Fig. 1, with PEG (i.e. an alkoxylated segment based on ethylene oxide) is the hydrophilic segment:
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Preferred polyols used as the central core molecule (corresponding to the claimed R1) include glycerol and pentaerythritol (p. 3-4, [0042]). These read on multi-functional oxygen-containing polyols with 3 (glycerol) or 4 (pentaerythritol OH groups (i.e. oxygen-containing reactive sites). The number of OH groups in these polyols will correspond to the claimed variable z in the resulting copolymer (i.e. z=3 or 4).
The hydrophobic polymer segment corresponds to the following portion of the formula recited in Claim 1:
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This segment may be a polyalkylene oxide other than PEG, such as polypropylene oxide (PPO) or polybutylene oxide (PBO), with hydrophobic segments having a molecular weight of about 5,000 specifically identified as being useful (p. 4, [0044]). This reads on the indicated segment where R2 is CH3 or CH2CH3 and x is either approximately 86 (PPO) or 69 (PBO), which falls within the claimed range of 1 to 200.
Alternatively, the hydrophobic segment can have a molecular weight of as low as 500 with an upper limit of 40,000 (p. 4, [0044]), corresponding to x=7 (PBO, Mw=500) to 689 (PPO, Mw=40,000). This overlaps the claimed range.
The hydrophilic polymer segment corresponds to the following portion of the formula recited in Claim 1:
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The hydrophilic polymer segment is preferably polyethylene glycol (PEG) hav a preferred molecular weight of about 1,000 to about 20,000 (p. 4, [0047]-[0048]). This reads on the indicated segment where y ranges from about 22 to about 454, which overlaps the claimed range of 1 to 250.
The PEG polymer segment may further include one or more capping groups covalently attached at a terminus of the PEG segment distal from the point of attachment to the hydrophobic polymer. The capping group can be a relatively inert group, such as an alkoxy group. Alternatively, the capping group can be a reactive functional group such as a protected carboxylic acid (p. 5, [0062]). When the chemically reactive group is a carboxylic acid, the protecting group may be a t-butyl group (p. 5, [0063]). This reads on the claimed R3 group where R3 is a hydrophobic carbon chain containing 4 carbons.
When a multi-functional polyol such as glycerol or pentaerythritol including 3 or 4 OH groups is employed and capping groups are included on all segments, the number of R3 groups will be 3 or 4. This falls within the claimed range of 2 to 4.
As indicated above, Zhao teaches ranges which overlap the claimed ranges. It would have been obvious to one of ordinary skill in the art at the time of filing to select values from the portion of the prior art ranges which overlap (and therefore fall within) the claimed ranges, as they are expressly identified by the prior art as being suitable. A prima facie case of obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05(I). Zhao as applied above reads on Claims 1-3 and 5-10.
Regarding Claim 4, as indicated above, exemplary hydrophobic segments include PPO having a molecular weight of about 5,000 (p. 4, [0044]). Zhao also describes exemplary PEG segments having a molecular weight of about 5,000 (p. 4, [0048]). When hydrophobic and hydrophilic segments having approximately identical molecular weights are selected, the propylene oxide content will be approximately 50%.
Claims 11, 12, and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Zhao as applied to Claim 1 above, further in view of Mayol et al. (Carbohydrate Polymers, 2014, vol. 102, p. 110-116; cited in prior Office action).
Regarding Claims 11, 12, and 26, Zhao remains as applied above. Zhao’s copolymer includes hydrophilic and hydrophobic segments and is therefore understood to be amphiphilic. The copolymer is also described as providing a micellar structure. One of the aims of Zhao’s invention is to improve delivery of hydrophobic drugs (p. 1, [0005]). Zhao further suggests incorporation of functional groups such as carboxylic acids at the terminus of the PEG segments (p. 5, [0062]).
Zhao does not teach incorporation of octenylsuccinic anhydride (OSA) as claimed.
In the same field of endeavor, Mayol teaches modification of a hydrophilic polymer with OSA. The OSA-modified product is able to self-assemble into micelles, load a hydrophobic drug, and release the active molecule (i.e. drug) with controlled kinetics (Abstract). As shown in Fig. 1 (p. 112), the hydrophilic polymer is modified via reaction of OH groups with OSA, and results in incorporation of a terminal carboxylate functional group as well as the pendant octenyl group (i.e. a hydrophobic group).
It would have been obvious to one of ordinary skill in the art at the time of filing to select Mayol’s OSA as the terminal functional group of Zhao’s copolymer, as it is shown to impart the desired carboxylate functionality; demonstrates suitability for loading and release of hydrophobic drugs; is shown to be suitable for use in amphiphilic micelle-forming polymers; and would be expected to react with the terminal OH groups of Zhao’s PEG segments through a mechanism similar to that shown in Mayol’s Fig. 1. Modification in this way reads on Claims 11, 12, and 26.
Response to Arguments
Applicant's arguments filed May 21, 2026 have been fully considered but they are not persuasive.
The Applicant argues that Zhao either alone or in combination with Mayol does not teach controlling the degree of end group substitution such that only a limited subset of the available terminal groups is hydrophobically modified.
The Applicant’s characterization of the claims is inconsistent with the language of the claims. Claim 1, for example, recites a formula including end groups R3. The number of end groups is dictated by the variable z, which ranges from 3 to 10. The number of end groups which must be hydrophobic ranges from 2 to 4.
When z=3 or 4, the total number of R3 groups will be either 3 or 4. In these cases all available functional arms may be modified with hydrophobic end groups and the newly introduced limitation requiring 2 to 4 hydrophobic end groups will be satisfied. The claims do not positively recite that at least one R3 group is H, so partial functionalization is required only when 2 end groups are hydrophobic or when z is an integer of 5 to 10.
Zhao as applied above teaches branched copolymers based on multi-functional oxygen-containing polyols with 3 (glycerol) or 4 (pentaerythritol OH groups (i.e. oxygen-containing reactive sites). The number of OH groups in these polyols will correspond to the claimed variable z in the resulting copolymer (i.e. z=3 or 4). Thus, Zhao’s copolymers may be fully functionalized with hydrophobic end groups and still satisfy the amended claims.
Conclusion
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/ROBERT S JONES JR/ Supervisory Patent Examiner, Art Unit 1762
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