DETAILED ACTION
The amendment filed on 07/08/2026 has been entered and fully considered. Claims 83, 85-96 and 100-105 are pending, of which claim 90 and 102 are amended.
Response to Amendment
In response to amendment, the examiner withdraws rejection under 35 U.S.C. 112(b), and maintains rejection over the prior art established in the previous Office 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 .
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.
Claim(s) 83, 85-96 and 100-105 is/are rejected under 35 U.S.C. 103 as being unpatentable over Watkins (WO 2016/019140, IDS) in view of Warren (European Journal of Soil Science, 2018, IDS).
Regarding claim 83, Watkins discloses a universal lipid quantitative standard (ULQS) comprising a plurality of isotopically labeled lipid standards (par [0007]), wherein the plurality of isotopically labeled lipid standards includes at least one lipid species from one or more lipid classes selected from the group consisting of: a phospholipid class, a lysophospholipid class, a cholesterol ester class, a triacylglycerol class, a diacylglycerol class, a ceramide class, and a sphingomyelin class (par [0037][00105]).
Walkins teaches that “a method is provided for synthesizing one or more mixtures of lipid molecules representative of the composition of lipid molecular species present in one or more corresponding lipid classes in a sample of interest” (par [0007]). Claim 40 of Walkins further teaches that “composition for use as an internal standard comprising one or more mixtures of lipid molecules representative of the composition of lipid molecular species present in one or more corresponding lipid classes in a sample of interest, each mixture of lipid molecules comprising: a lipid backbone having an isotopically-labeled fatty acid at a first position on the lipid backbone, wherein the lipid backbone is for a lipid class having at least two acyl groups; and a mixture of at least two different fatty acids present at a separate position on the lipid backbone, wherein the mixture of fatty acids is representative of the fatty acids that occur in the corresponding lipid class in the sample of interest, and wherein each of the fatty acids in the mixture is present at a ratio representative of the ratio of occurrence of the fatty acid in the lipid molecular species present in the corresponding lipid class in the sample of interest.”. Here, Walkins teaches that the number of isotopically labeled lipid standards are the number of the potential corresponding lipid classes in a sample of interest.
Watkins teaches that lipid standards should be selected to represent the diversity of lipid molecular species across lipid classes, and that mixtures of lipid standards are constructed to reflect lipid composition in samples (claim 40).
Thus, Watkins establishes that:
the selection and number of lipid species is driven by achieving representative coverage of lipid diversity.
Warren teaches that LC-MS lipid analysis uses:
“a deuterium-labelled lipid mixture (Splash Lipidomix Mass Spec Standard, Avanti Polar Lipids, Alabaster, AB, USA) that contained lipid species from each of the major lipid classes” (page 792, par 7)
This teaching demonstrates that:
lipid standards are implemented as predefined mixtures,
comprising multiple lipid species across classes, and
selected to enable quantitative LC-MS analysis.
The prior art establishes that:
increasing the number of lipid standards improves coverage of lipid diversity, while
limiting the number reduces experimental complexity and cost
Thus, the number of lipid species in the mixture directly affects performance, and is therefore a result-effective variable.
Warren demonstrates that practitioners select finite sets of lipid species for practical implementation, confirming that the number of standards is chosen based on desired analytical performance.
Accordingly, selecting a specific number of lipid species per class would have been a matter of routine optimization to balance coverage and practicality.
In view of:
Watkins teaching representative multi-species lipid mixtures, and
Warren teaching implementation of such mixtures as predefined, multi-class lipid standard panels used in LC-MS,
it would have been obvious to a person of ordinary skill in the art to select a specific number of lipid species per class to achieve a desired balance between analytical coverage and experimental complexity.
Regarding claim 100, Watkins discloses a universal lipid quantitative standard (ULQS) comprising a plurality of isotopically labeled lipid standards (par [0007]).
Walkins teaches that “a method is provided for synthesizing one or more mixtures of lipid molecules representative of the composition of lipid molecular species present in one or more corresponding lipid classes in a sample of interest” (par [0007]). Claim 40 of Walkins further teaches that “composition for use as an internal standard comprising one or more mixtures of lipid molecules representative of the composition of lipid molecular species present in one or more corresponding lipid classes in a sample of interest, each mixture of lipid molecules comprising: a lipid backbone having an isotopically-labeled fatty acid at a first position on the lipid backbone, wherein the lipid backbone is for a lipid class having at least two acyl groups; and a mixture of at least two different fatty acids present at a separate position on the lipid backbone, wherein the mixture of fatty acids is representative of the fatty acids that occur in the corresponding lipid class in the sample of interest, and wherein each of the fatty acids in the mixture is present at a ratio representative of the ratio of occurrence of the fatty acid in the lipid molecular species present in the corresponding lipid class in the sample of interest.”. Here, Walkins teaches that the number of isotopically labeled lipid standards are the number of the potential corresponding lipid classes in a sample of interest.
Watkins teaches that lipid standards should be selected to represent the diversity of lipid molecular species across lipid classes, and that mixtures of lipid standards are constructed to reflect lipid composition in samples (claim 40).
Thus, Watkins establishes that:
the selection and number of lipid species is driven by achieving representative coverage of lipid diversity.
Warren teaches that LC-MS lipid analysis uses:
“a deuterium-labelled lipid mixture (Splash Lipidomix Mass Spec Standard, Avanti Polar Lipids, Alabaster, AB, USA) that contained lipid species from each of the major lipid classes” (page 792, par 7)
This teaching demonstrates that:
lipid standards are implemented as predefined mixtures,
comprising multiple lipid species across classes, and
selected to enable quantitative LC-MS analysis.
The prior art establishes that:
increasing the number of lipid standards improves coverage of lipid diversity, while
limiting the number reduces experimental complexity and cost
Thus, the number of lipid species in the mixture directly affects performance, and is therefore a result-effective variable.
Warren demonstrates that practitioners select finite sets of lipid species for practical implementation, confirming that:
the number of standards is chosen based on desired analytical performance.
Accordingly, selecting a specific number of lipid species per class would have been a matter of routine optimization to balance coverage and practicality.
In view of:
Watkins teaching representative multi-species lipid mixtures, and
Warren teaching implementation of such mixtures as predefined, multi-class lipid standard panels used in LC-MS,
it would have been obvious to a person of ordinary skill in the art to select a specific number of lipid species per class to achieve a desired balance between analytical coverage and experimental complexity.
Regarding claim 85, Watkins discloses that wherein the phospholipid species, the lysophospholipid species, the cholesterol ester species, the triacylglycerol species, the diacylglycerol species, the ceramide species, and the sphingomyelin species lipid species for each lipid class are selected (par [0037][00105]).
“to correct for ionization efficiency, extraction efficiency, and differential fragmentation efficiency in a mass spectrometry analysis”, a stable isotope-labeled analog of the analyte is typically used as an internal standard; this means a molecule with the same chemical structure as the analyte but with a different isotopic mass (like deuterium substitution) that allows the mass spectrometer to distinguish between the analyte and the internal standard while still behaving similarly throughout the analytical process.
Besides, the phrase “to correct for at least one of the following: ionization efficiency, extraction efficiency, and differential fragmentation efficiency of the lipid species in a sample” merely describes an intended result and does not further limit the structure of the ULQS, therefore caried no weight in the patentability determination.
Regarding claim 86, Watkins discloses that wherein the phospholipid includes one or more phospholipid species selected from the group consisting of: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylglycerol (PG), and phosphatidylinositol (Pl) (par [00105]).
Regarding claim 87, Watkins discloses that wherein the phospholipid species are represented by the general formula I, except the location of the deuterium substitution (Fig. 2, par [0057]):
wherein:
R1 is -(CH2)n-N(CH3)3, -(CH2)n-NH3, -(CH2)n-C(H)(NH3)-C(O)-O-, -(CH2)n-CH(OH)-CH(OH),
inositol, and H;
n is 1 to 6;
R2 is a C3 to C30 saturated or unsaturated acyl chain;
R3 is a C3 to C30 saturated or unsaturated acyl chain; and
R4 is independently H.
In a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
1. Mass Shift
The purpose of isotopic labeling in MALDI-MS is often to introduce a mass difference between the labeled and unlabeled compound for unambiguous identification or quantification.
As long as the isotope is incorporated into the molecule and does not get lost during ionization, its position typically does not affect the mass shift observed.
2. Ionization Efficiency
The position of the isotope can sometimes influence ionization efficiency due to subtle changes in the molecule's chemical properties. For example:
2H (deuterium) at exchangeable sites (e.g., hydroxyl or amine hydrogens) can undergo back-exchange with the solvent or matrix, potentially reducing the observed labeling.
3. Calibration and Quantification
In MALDI-MS quantitative analysis, isotopically labeled compounds are often used as internal standards. The label should be placed in a non-exchangeable position to ensure that the labeled standard behaves identically to the analyte during ionization and detection.
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Indeed, in the instant claim 93, the deuterium substitution is on the backbone of sphingolipid.
Regarding claim 88, Watkins discloses that wherein the lysophospholipid includes one or more selected from the group consisting of: lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), lysophosphatidylsphoserine (LPS), lysophosphatidylglycerol (LPG), and lysophosphatidylinositol (LPI) (par [00105]).
Regarding claim 89 and 101, Watkins discloses that wherein the lysophospholipid species are represented by the general formula II, except the location of the deuterium substitution:
wherein:
R1 is -(CH2)n-N(CH3)3, -(CH2)n-NH3, -(CH2)n-C(H)(NH3)-C(O)-O-, -(CH2)n-CH(OH)-CH(OH), inositol, and H;
n is 1 to 6;
R2 is a C2 to C24 saturated or unsaturated acyl chain; and
R4 is independently H.
As has been discussed regarding claim 87 above, in a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Regarding claim 89, Watkins discloses that wherein the lysophospholipid species are represented by the general formula II, except the location of the deuterium substitution:
wherein:
R1 is -(CH2)n-N(CH3)3, -(CH2)n-NH3, -(CH2)n-C(H)(NH3)-C(O)-O-, -(CH2)n-CH(OH)-CH(OH), inositol, and H;
n is 1 to 6;
R2 is a C2 to C24 saturated or unsaturated acyl chain; and
R4 is independently H.
As has been discussed regarding claim 87 above, in a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Regarding claim 90 and 102, Watkins discloses that wherein the cholesterol ester species are represented by the general formula III, or a pharmaceutically acceptable salt thereof (Fig. 9, par [00144][0051]):
wherein:
R2 is a C9 to C29 saturated or unsaturated acyl chain; and
R4 is independently H or an isotope of H, provided that at least one of R4 is an isotope of H.
Regarding claim 91 and 103, Watkins discloses that wherein the triacylglycerol class includes one or more triacylglycerol species, and wherein the triacylglycerol species are represented by the general formula IV, except the location of the deuterium substitution (Fig. 7, par [0062]):
R2 is a C3 to C30 saturated or unsaturated acyl chain;
R3 are each independently a C3 to C25 saturated or unsaturated acyl chain; and
R4 is independently H.
As has been discussed regarding claim 87 above, in a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Regarding claim 92 and 104, Watkins discloses that wherein the diacylglycerol class includes one or more diacylglycerol species, wherein the diacylglycerol species are represented by the general formula V, except the location of the deuterium substitution:
wherein:
R2 is a C3 to C30 saturated or unsaturated acyl chain;
R3 is a C3 to C25 saturated or unsaturated acyl chain; and
R4 is independently H.
As has been discussed regarding claim 87 above, in a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Regarding claim 93 and 105, Watkins discloses that wherein the ceramide class includes one or more ceramide species, wherein the ceramide species are represented by the general formula VI, or a pharmaceutically acceptable salt thereof (with an isotopically-labeled sphingolipid backbone) (par [0051]):
wherein:
R2 is a C10 to C30 saturated or unsaturated acyl chain; and
R4 is independently H or an isotope of H, provided that at least one of R4 is an isotope of H.
Regarding claim 94, Watkins discloses that wherein the sphingomyelin class includes one or more sphingomyelin species, wherein the sphingomyelin species are represented by the general formula VII, except the location of the deuterium substitution (par [0051]).
As has been discussed regarding claim 87 above, in a MALDI (Matrix-Assisted Laser Desorption/Ionization) mass spectrum, where the compound does not fragment, the location of isotopic labeling generally matters less compared to techniques where fragmentation occurs. However, there are still important considerations:
Since the difference of the location of deuterium substitution between Watkins and the instant claim does not affect the above considerations, the difference is merely a design of choices.
Regarding claim 95-96, Since the difference of the location of deuterium substitution between Watkins and the instant claims do not affect the above considerations, the difference is merely a design of choices.
Response to Arguments
Applicant's arguments filed 07/08/2026 have been fully considered but they are not persuasive.
Applicant’s amendment correcting general formula III in the specification and in claims 90 and 102 has been considered. The amended formula now clearly depicts the intended cholesterol side-chain structure. Accordingly, the rejection of claims 90 and 102 under 35 U.S.C. §112(b) is withdrawn.
Regarding the rejection under 35 U.S.C. §103, Applicant argues that Watkins and Warren do not identify a finite number of predictable solutions leading to the particular panels of 42, 64, or 69 lipid standards recited in claims 83 and 100; that the asserted prior art presents a vast number of possible combinations; and that arriving at the claimed numbers and distribution among seven lipid categories would require hindsight and undue experimentation. These arguments have been considered but are not persuasive.
The rejection does not rely merely on the general proposition that any arbitrary mixture of lipid standards could have been selected. Watkins expressly recognizes that using only one standard per broad lipid class provides inadequate representation of lipid diversity and teaches producing internal-standard mixtures containing “up to 10 fatty acids per lipid class,” with the fatty acids selected “to represent the diversity of chemical structures (lipid molecular species)” present in the sample. Watkins further teaches assigning remaining analytes to the closest internal-standard analogue and calculating the total concentration for each lipid class. Thus, Watkins expressly identifies both the variable to be adjusted—the number and identity of representative lipid species within each class—and the result affected by that variable—coverage of the structural diversity of the analytes.
Watkins also provides a directed selection procedure rather than an unrestricted universe of possibilities. Watkins teaches selecting fatty acids based on representative degrees of unsaturation and relative abundance in the sample, assigning selected species as high- or low-abundance components, and completing the mixture with the most abundant remaining fatty acids. Watkins therefore directs the skilled artisan toward standards representative of the expected sample composition, rather than toward arbitrary combinations. Watkins additionally provides internal standards for ten lipid classes and specific mixtures listed in its tables.
Warren confirms that this teaching had been implemented in practice before the effective filing date. Warren states that method development used “a deuterium-labelled lipid mixture (Splash Lipidomix Mass Spec Standard …) that contained lipid species from each of the major lipid classes.” The evidence submitted by Applicant further identifies that SPLASH product as a single-vial, premixed quantitative standard containing fourteen deuterium-labeled components representing major lipid classes, with the concentration of each class optimized for plasma analysis. Warren therefore corroborates that skilled artisans selected a finite, predefined number and distribution of labeled standards across lipid classes according to the sample and analytical application.
Applicant’s characterization of SPLASH as its “first generation” product and the claimed ULQS as a “second generation” product does not establish nonobviousness. That characterization instead confirms that increasing the number of representative standards and expanding coverage within lipid classes constituted development along the same known design objective identified by Watkins: improving representation of lipid diversity. The fact that the commercial products contain different total numbers does not, by itself, demonstrate that the claimed numbers produce a new or unexpected technical effect.
Moreover, KSR does not require every obviousness rejection to be based exclusively on the “finite number of identified, predictable solutions” rationale. Here, the rejection is also based on optimization of a recognized result-effective variable. Watkins expressly teaches that broader structural representation provides better analytical coverage and teaches adjusting the number and identity of standards according to the lipid species expected in the sample. Once the number of representative standards was recognized as affecting analytical coverage, determining how many standards to include for each relevant lipid category would have involved selecting and testing a finite panel using the disclosed abundance, chain-length, and unsaturation criteria. Warren’s successful use of a predefined multi-class deuterated panel provides a reasonable expectation that such expanded panels would function for LC–MS analysis.
Applicant has not provided comparative evidence showing that the particular distributions recited in alternatives (a), (b), or (c)—rather than neighboring panel sizes or distributions—produce an unexpected result or represent a critical threshold. Nor has Applicant identified any technical obstacle that would have prevented the skilled artisan from preparing and testing additional isotopically labeled species using Watkins’ disclosed selection framework. Attorney argument that the number of possible combinations is large does not, without supporting evidence, establish that the selection would have required undue experimentation.
Accordingly, Watkins’ express teaching to vary the number and identity of lipid standards to obtain representative coverage, considered with Warren’s practical use of a predefined deuterium-labeled, multi-class standard mixture in LC–MS, provides articulated reasoning with a rational underpinning for selecting particular finite numbers of representative species for the recited lipid categories. The rejection of claims 83, 85–96, and 100–105 under 35 U.S.C. §103 over Watkins in view of Warren is therefore maintained.
Conclusion
THIS ACTION IS MADE FINAL. 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.
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/XIAOYUN R XU, Ph.D./ Primary Examiner, Art Unit 1797
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