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 .
Election/Restrictions
Applicant’s election without traverse of Group I (25-36 and 47), drawn to a method for detecting the presence or absence of tenofovir diphosphate in a fluid sample, in the rely filed on 06/03/2026 is acknowledged. Hence, claims 37-46 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
Status of the Claims
Claims 25-47 are pending. Claims 37-46 are withdrawn. Claims 25-36 and 47 are examined herein in view of the restriction.
Priority
The present application, filed 09/29/2023, is a continuation-in-part of 16/755,100, filed 04/09/2020, which is a 371 of PCT/US2018/055961, filed 10/15/2018, which claims benefit of U.S. Provisional Patent Application 62/572,126, filed 10/13/2017. MPEP §2152.01(B) provides that if an application is a continuation-in-part of an earlier U.S. application or international application, any claims in the new application not supported by the specification and claims of the parent application have an effective filing date equal to the actual filing date of the new application. Any claims which are fully supported under 35 U.S.C. 112 by the earlier parent application have the effective filing date of that earlier parent application. Pending independent claims 25, 26, and 47 each require contacting a fluid sample with a phosphatase to convert tenofovir diphosphate (TFV-DP), if present, to tenofovir (TFV), either before application of the fluid sample to a sample pad or after application of the fluid sample to the sample pad.
The 10/13/2017 provisional application, the 10/15/2018 PCT application, and the corresponding U.S. 371 application do not provide written-description support for this phosphatase-mediated TFV-DP-to-TFV conversion. Although the earlier disclosures describe tenofovir-based lateral-flow assays, anti-TFV antibodies, biological samples, competitive assay configurations, and related assay components, they do not disclose contacting a TFV-DP-containing fluid sample with phosphatase to convert TFV-DP to TFV as presently claimed. The U.S. § 371 specification, for example, describes lateral-flow detection of an NRTI or NRTI metabolite but does not disclose the claimed TFV-DP/phosphatase conversion.
The 09/29/2023 continuation-in-part specification first expressly provides this subject matter. The CIP describes methods in which a fluid sample is contacted with phosphatase to convert TFV-DP to TFV, expressly defines TFV-DP, identifies phosphatases capable of dephosphorylating TFV-DP to TFV, and provides experimental examples demonstrating TFV-DP-to-TFV conversion in PBS and whole-blood samples followed by lateral-flow detection. The CIP further expressly identifies phosphatase derived from sweet potato extract, as recited in dependent claim 31.
Accordingly, because claims 25, 26, and 47 contain subject matter first adequately supported in the 09/29/2023 continuation-in-part application, those claims have an effective filing date of 09/29/2023. Claims 27–36 depend from claim 25 and therefore incorporate the same phosphatase-mediated TFV-DP-to-TFV conversion limitation. Consequently, claims 25–36 and 47 are accorded an effective filing date of 09/29/2023.
Information Disclosure Statement
The Information Disclosure Statement filed 12/05/2023 is acknowledged and have been considered. The Information Disclosure Statement filed 09/29/2023 is acknowledged and have been considered except for the following reference: “KOENIG et al. "Urine assay for tenofovir to monitor adherence in real time to tenofovir disoproxil fumarate/emtricitabine as pre-exposure prophylaxis", HIV Medicine, 2017, pp. 412-418, Vol. 18, No. 6, British HIV Association.” The reference fails to comply with 37 CFR 1.98(a)(2), which requires a legible copy of each cited foreign patent document; each non-patent literature publication or that portion which caused it to be listed; and all other information or that portion which caused it to be listed. It has been placed in the application file, but the information referred to therein has not been considered. Additionally, a conference abstract related to the above-identified reference has been submitted in the application file; however, the conference abstract is not identified on either of the Information Disclosure Statements. Accordingly, the conference abstract has not been considered.
Claim Objections
Claim 27objected to because of the following informalities: Claim 27 recites “the fluid sample is a urine.” The phrase “a urine” is grammatically improper and should be corrected. The claim should be amended to recite, for example, “the fluid sample is urine, whole blood, blood serum, blood plasma, sweat, mucous, saliva, milk, semen, or sputum sample.” Appropriate correction is required.
Claim 28 is objected to because of the following informalities: Claim 28 improperly designates its alternatives as (a), (b), (c), and (e), thereby omitting paragraph designation (d). The claim should be amended to provide sequential paragraph designations, for example (a), (b), (c), and (d). Appropriate correction is required.
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 25-36 and 47 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 25 is indefinite because step (d) recites that the membrane comprises “a second reagent bound to the membrane to form a test line,” but subsequently recites “wherein the second is a tenofovir derivative conjugated to a carrier (tenofovir derivative conjugate).” The term “the second” lacks proper antecedent basis because no element identified merely as “a second” was previously introduced. Although claim 25 previously introduces a “second reagent,” the claim does not expressly identify “the second” as that second reagent. Accordingly, it is unclear from the claim language whether “the second” is intended to refer to the previously recited second reagent or to some other element.
Claim 25 is further indefinite because step (e) recites “wherein detecting the detectable signal indicates the absence of tenofovir diphosphate in the fluid sample at the time the sample was obtained from the individual.” Claim 25 does not previously introduce “a detectable signal.” Rather, step (e) first recites “detecting the labeled first reagent-second reagent complex, if formed at the test line,” and thereafter refers to “the detectable signal.” Thus, the antecedent basis for “the detectable signal” is unclear. For purposes of compact prosecution, the phrase “wherein the second is a tenofovir derivative conjugated to a carrier” will be interpreted as meaning “wherein the second reagent is a tenofovir derivative conjugated to a carrier.” Also, the phrase “the detectable signal” will be interpreted as referring to a detectable signal produced by or associated with the labeled first reagent-second reagent complex formed at the test line. These interpretations are made solely to permit examination of the claim on the merits and do not waive the requirement that Applicant amend the claim to clearly define the claimed subject matter.
Claims 27–36 are rejected under 35 U.S.C. 112(b) because they depend from claim 25 and therefore incorporate all of the limitations of claim 25, including the indefinite limitations discussed above. Accordingly, the indefiniteness of claim 25 is carried into claims 27–36.
Claim 26 is rejected under 35 U.S.C. 112(b) because step (d) introduces “a tenofovir derivative conjugate bound to the membrane upstream of a second reagent bound to the membrane to form a test line,” whereas step (d)(i) subsequently recites that, if tenofovir is absent, “the labeled first reagent is allowed to bind to the tenofovir derivative without binding to the second reagent.” A separate “tenofovir derivative” has not previously been introduced in claim 26. Moreover, step (d)(ii) expressly returns to the terminology “the tenofovir derivative conjugate.” It is therefore unclear whether “the tenofovir derivative” in step (d)(i) is intended to refer to the previously recited tenofovir derivative conjugate or to a different, unconjugated tenofovir derivative. Claim 26 is further indefinite because step (e) recites “wherein detecting the detectable signal indicates the presence of tenofovir diphosphate in the fluid sample at the time the sample was obtained from the individual.” Claim 26 does not previously introduce “a detectable signal.” Instead, step (e) first recites detecting the labeled first reagent-second reagent complex at the test line and thereafter refers to “the detectable signal.” Accordingly, the antecedent basis for “the detectable signal” is unclear. For purposes of compact prosecution, the phrase “the tenofovir derivative” in claim 26(d)(i) will be interpreted as referring to the previously recited tenofovir derivative conjugate bound to the membrane. Also, the phrase “the detectable signal” will be interpreted as referring to a detectable signal produced by or associated with the labeled first reagent-second reagent complex formed at the test line. These interpretations are made solely to permit examination of the claim on the merits and do not waive the requirement that Applicant amend the claim to clearly define the claimed subject matter.
Claim 34 is additionally rejected under 35 U.S.C. 112(b) as being indefinite because claim 34 depends from claim 25 and recites that “the third reagent binds to the labeled first reagent to cause the label to form a detectable signal at the control line.” Neither claim 34 nor claim 25, from which claim 34 depends, previously introduces “a third reagent” or “a control line.” Rather, a third reagent bound to the membrane to form a control line is introduced in claim 33, from which claim 34 does not depend. Accordingly, the phrases “the third reagent” and “the control line” lack proper antecedent basis, and it is unclear from the claim language what particular third reagent and control line are being referenced. Claim 34 is further indefinite because it recites the phrase “the label.” Neither claim 34 nor claim 25 previously introduces “a label.” Rather, claim 25 introduces a “labeled first reagent.” Accordingly, the phrase “the label” lacks express antecedent basis, and it is unclear from the claim language what particular label is being referenced. For purposes of compact prosecution, the phrases “the third reagent” and “the control line” will be interpreted as referring to a third reagent bound to the membrane to form a control line, consistent with the third reagent and control line recited in claim 33. The phrase “the label” will be interpreted as referring to the label associated with the previously recited labeled first reagent. This interpretation is made solely to permit examination of the claim on the merits and does not waive the requirement that Applicant amend the claim to clearly define the claimed subject matter.
Claim 36 is additionally indefinite because it recites “the carrier of the second reagent is BSA conjugate.” Claim 25, from which claim 36 depends, recites the second reagent as a tenofovir derivative conjugated to a carrier. Claim 36 therefore creates uncertainty as to whether Applicant intends the carrier itself to be BSA, intends the carrier to be some unspecified BSA conjugate, or intends the second reagent as a whole to be a tenofovir-BSA conjugate. For purposes of compact prosecution, claim 36 will be interpreted as requiring that the carrier is BSA, such that the recited second reagent is a tenofovir-BSA conjugate. This interpretation is made solely to permit examination of the claim on the merits and does not waive the requirement that Applicant amend the claim to clearly define the claimed subject matter.
Claim 47 is rejected under 35 U.S.C. 112(b) as being indefinite because step (d) recites “detecting the label at the labeled first reagent-second reagent complex, if formed at the test line.” Although claim 47 previously introduces a “labeled first reagent,” it does not expressly introduce “a label” before subsequently referring to “the label.” Accordingly, the phrase “the label” lacks express antecedent basis, and it is unclear from the claim language what particular label is intended. Claim 47 is further indefinite because the same step recites “wherein detecting the detectable signal indicates the absence of tenofovir diphosphate.” Claim 47 does not previously introduce “a detectable signal.” Rather, the claim recites detecting “the label” at the labeled first reagent-second reagent complex and thereafter refers to “the detectable signal.” Accordingly, “the detectable signal” likewise lacks proper antecedent basis. For purposes of compact prosecution, the phrase “the label” will be interpreted as referring to the label associated with the previously recited labeled first reagent, and the phrase “the detectable signal” will be interpreted as referring to the detectable signal produced by or associated with that label when the labeled first reagent-second reagent complex is formed at the test line. These interpretations are made solely to permit examination of the claim on the merits and do not waive the requirement that Applicant amend the claim to clearly define the claimed subject matter.
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 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention 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 35 U.S.C. 103 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 the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 25-36 and 47 are rejected under 35 U.S.C. 103 as being unpatentable over Daughtridge et al. (WO 2019/075487 A1) in view of Sevenler et al. (Immunoassay for HIV Drug Metabolites Tenofovir and Tenofovir Diphosphate. ACS Infectious Diseases. Vol. 6, No. 7, May 2020), King et al. (Liquid Chromatography–Tandem Mass Spectrometric Determination of Tenofovir-Diphosphate in Human Peripheral Blood Mononuclear Cells. Journal of Chromatography B. Vol. 843, No. 2, July 2006), and Inoue et al. (Liquid Chromatography Assay for Routine Monitoring of Cellular Ribavirin Levels in Blood. Antimicrobial Agents and Chemotherapy. Vol. 48, No. 10, October 2004).
Regarding claim 25, Daughtridge teaches a method for performing a lateral flow assay for detecting the presence or absence of tenofovir or a tenofovir metabolite in a fluid sample obtained from an individual. Daughtridge teaches that the disclosed antibodies can be employed in immunodiagnostic assays, including lateral flow immunodiagnostic assays, to detect the presence of tenofovir in patient samples, including urine samples (p. 2). Daughtridge further teaches monitoring the presence or absence of nucleoside reverse transcriptase inhibitor (NRTI; e.g., tenofovir or a tenofovir metabolite) in a biological fluid sample, including through competitive and lateral flow immunoassays, and preferably through a rapid immunoassay platform such as lateral flow (pp. 30–31).
Regarding limitation (a), Daughtridge teaches applying the fluid sample to a sample pad, specifically applying said fluid sample to a sample pad (p. 6). Daughtridge further teaches that the lateral-flow strip includes a sample pad that contains the buffering and sample treatment materials (p. 49).
Regarding limitation (b), Daughtridge teaches allowing said sample to flow laterally along the sample pad to a conjugated label pad; wherein said conjugated label pad comprises a first reagent conjugated to a detectable label, and wherein a portion of the conjugated label pad and a portion of the sample pad forms a first interface (p. 6). Daughtridge further teaches embodiments wherein the first reagent is an antibody and the antibody is conjugated to a detectable label (p. 10). Daughtridge specifically provides antibodies that specifically bind to tenofovir or the tenofovir moiety of tenofovir derivatives (p. 42).
Regarding limitation (c), Daughtridge teaches competitive immunoassays wherein free target drug binds the anti-drug antibody. In particular, Daughtridge teaches that if an antibody is specific for a metabolite (e.g., NRTI), then the presence of the metabolite in a reaction containing labeled NRTI derivative and the antibody will reduce the amount of labeled NRTI derivative bound to the antibody (p. 18). Daughtridge further teaches anti-TFV antibodies that specifically bind tenofovir (p. 42). Accordingly, when TFV is present in the sample and encounters the labeled anti-TFV first reagent, the TFV binds the labeled first reagent to form the claimed labeled first reagent-TFV complex.
Regarding limitation (d), Daughtridge teaches allowing said sample to flow laterally along the conjugated label pad to a membrane; wherein a portion of the membrane and a portion of the conjugated label pad forms a second interface; and wherein said membrane comprises at least one second reagent bound to the membrane to form a test line (p. 6). Daughtridge further teaches lateral-flow membranes onto which lines of reagents are applied (pp. 48–49). Regarding the second reagent being a tenofovir derivative conjugated to a carrier, Daughtridge teaches NRTI-derivative conjugates and expressly defines such conjugates as an NRTI derivative conjugated to a carrier protein, including carrier proteins such as KLH, BSA, etc. (p. 21). Daughtridge also teaches embodiments wherein the second reagent is a compound or a conjugated derivative of the same (pp. 10-11). Thus, Daughtridge teaches an immobilized tenofovir-derivative conjugate suitable for forming the test line.
Regarding limitation (d)(i), wherein, if TFV is present, the labeled first reagent-TFV complex flows past the test line without binding the second reagent, Daughtridge teaches the underlying competitive binding principle whereby target drug competes with a drug derivative for binding to an anti-drug antibody. Daughtridge explains that, when an antibody is specific for a metabolite (e.g., NRTI), then the presence of the metabolite in a reaction containing labeled NRTI derivative and the antibody will reduce the amount of labeled NRTI derivative bound to the antibody (p. 18). Daughtridge further expressly teaches a negative-read competitive lateral-flow embodiment wherein the conjugate pad contains a label linked to an antibody made to the drug substance and the solid support, such as nitrocellulose, has a derivative of the target drug striped onto it (p. 50). Daughtridge teaches that, in this configuration, the absence of a test line indicates that the subject had been taking the target drug (p. 50). Thus, when TFV is present and binds the labeled anti-TFV first reagent, the labeled first reagent-TFV complex does not bind the immobilized TFV derivative at the test line, resulting in absence of the test-line signal.
Regarding limitation (d)(ii), wherein, if TFV is absent, the labeled first reagent binds the second reagent to form a labeled first reagent-second reagent complex at the test line, Daughtridge expressly teaches the same negative-read competitive lateral-flow configuration comprising a conjugate pad containing a label linked to an antibody made to the drug substance and a solid support, such as nitrocellulose, having a derivative of the target drug striped onto it (p. 50). Daughtridge further teaches that the presence of a line in the test zone indicates that the subject had not been routinely taking the target drug (p. 50). Thus, when TFV is absent, the labeled anti-TFV first reagent remains available to bind the immobilized TFV derivative at the test line, forming the labeled first reagent-second reagent complex and producing the test-line signal.
Regarding limitation (e), Daughtridge teaches detecting the detectable label associated with the complex formed at the test line. Daughtridge teaches that deposited detection labels may provide a visual indication (colloidal gold, colored latex or other labels known to those skilled in the art) or may comprise labels requiring an instrument for measurement, including fluorescence and chemiluminescence, with the end result producing the appearance or absence of a colored line or spot (pp. 48–49). Daughtridge expressly teaches in its labeled-antibody/immobilized-drug-derivative negative-read embodiment that the presence of a line in the test zone indicates absence of the target drug, whereas absence of the line indicates presence of the target drug (p. 50). Accordingly, detection of the test-line signal corresponds to absence of TFV.
Daughtridge additionally supplies an express reason to improve the assay because it identifies a great need for a point-of-care (POC) test for monitoring pre-exposure prophylaxis (PrEP) adherence that provides noninvasive, painless, quantitative, affordable, and rapid results (p. 1) and teaches rapid lateral-flow detection of NRTIs and their metabolites.
However, Daughtridge does not specifically teach contacting a fluid sample with a phosphatase to convert TFV-DP, if present in the fluid sample, to TFV, either before applying the fluid sample to the sample pad or after applying the fluid sample to the sample pad and before detection of TFV using the disclosed lateral-flow assay.
Sevenler addresses the reason one of ordinary skill would specifically extend Daughtridge’s TFV adherence assay to TFV-DP. Sevenler teaches that TFV-DP that has accumulated in red blood cells (RBCs) has a half-life of 17 days, whereas TFV has a substantially shorter plasma residence, and expressly teaches that TFV-DP concentration in red blood cells is highly correlated with average dosing (pp. 1635-1636, Fig. 1A). Sevenler consequently states that competitive immunoassays are a mature and proven approach in rapid diagnostic test development and develops immunoassays to measure both TFV and TFV-DP in plasma and red blood cells toward the long-term goal of developing a rapid diagnostic test (p. 1636). Sevenler further demonstrates detection of TFV-DP in blood cell lysate using antibody 1H11 and immobilized TFV-NH (p. 1638, Fig. 4B) and teaches that blood cells were pelleted and lysed by surfactant for TFV-DP detection (p. 1637). Finally, Sevenler expressly teaches that the optimized assay could then be tested with PrEP patient samples to assess the utility of the test, and the optimized assay could then be translated to a lateral flow format to enable the rapid point-of-care assessment of both short- and long-term drug adherence (p. 1638). Thus, Sevenler provides an express bridge from Daughtridge’s TFV lateral-flow adherence assay to detection of TFV-DP as the longer-term adherence marker. Sevenler, however, does not teach converting TFV-DP to TFV with phosphatase.
King supplies that precise conversion. King teaches that human peripheral blood mononuclear cells (hPBMCs) were harvested from whole blood, lysed, after which TFV-DP was dephosphorylated with acid phosphatase to form TFV, and further teaches that the resulting TFV concentrations directly correspond with the intra-hPBMC TFV-DP concentration (Abstract, p. 147). More particularly, King teaches that isolated TFV-DP solution was dephosphorylated to TFV with the addition of acid phosphatase/sodium acetate working stock solution and incubated at 37°C for one hour (Experimental, p. 149). King further validates the reaction by determining that 1 h of incubation was sufficient to convert greater than 96% of TFV-DP to TFV (Results and discussion, p. 152). King therefore expressly teaches the exact TFV-DP→phosphatase→TFV biochemical conversion required by limitation (a), together with evidence that the converted TFV quantitatively represents the starting TFV-DP. King performs phosphatase treatment after isolation of TFV-DP and therefore does not expressly teach simplifying the process by contacting the blood-derived sample/lysate directly with phosphatase.
Inoue supplies that known sample-processing modification. Inoue concerns intracellular phosphorylated metabolites of the antiviral nucleoside analog ribavirin and expressly teaches that whole blood diluted with a sixfold volume of ice-cold distilled water was subjected to acid phosphatase digestion to convert phosphorylated ribavirin metabolites to free ribavirin (Abstract, p. 3813). Inoue’s method specifically teaches that whole blood supplemented with 120 ul of ice-cold distilled water was vortexed to accomplish complete hemolysis and that the hemolysate was treated with acid phosphatase to hydrolyze the phosphorylated metabolites before column extraction and detection (Materials and Methods, p. 3813). Importantly, Inoue expressly explains the reason for this modification: the earlier dephosphorylation procedure was too tedious to use for routine monitoring of cellular ribavirin and the disclosed process simplified the dephosphorylation procedure (p. 3813). Inoue further reports that dephosphorylation of the phosphorylated metabolites of ribavirin went to completion, with a plateau reached at 30 min (Materials and Methods, p. 3814). Thus, Inoue teaches that for an analogous intracellular phosphorylated antiviral analyte, a blood-derived lysate/hemolysate can be directly contacted with phosphatase before downstream detection, specifically to simplify routine analysis.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Daughtridge’s TFV-specific competitive lateral-flow adherence assay in view of Sevenler, King, and Inoue so that a TFV-DP-containing blood-derived fluid sample is contacted with phosphatase to convert TFV-DP to TFV before the resulting TFV is assayed using Daughtridge’s labeled anti-TFV first reagent and membrane-bound tenofovir-derivative conjugate. The prior art itself provides the teaching, suggestion, and motivation for each modification: Daughtridge expressly seeks rapid point-of-care monitoring of tenofovir/NRTI metabolites; Sevenler expressly identifies RBC TFV-DP as a longer-lived marker correlated with average dosing and proposes translating TFV/TFV-DP competitive immunochemistry to lateral flow; King expressly teaches converting the same claimed analyte, TFV-DP, to TFV with acid phosphatase so that the resulting TFV corresponds to the original TFV-DP concentration; and Inoue expressly teaches simplifying analysis of analogous intracellular phosphorylated antiviral metabolites by performing phosphatase digestion directly on a blood hemolysate before downstream analysis. The skilled artisan therefore would have had reason to use King’s known TFV-DP-to-TFV conversion to render TFV-DP detectable by Daughtridge’s existing TFV-specific lateral-flow chemistry and, following Inoue’s express simplification teaching, to perform that enzymatic conversion directly on the blood-derived fluid/lysate rather than first requiring analyte-specific chromatographic isolation, thereby providing a rapid assay capable of reflecting the longer-term adherence information identified by Sevenler. There would have been a reasonable expectation of success because Daughtridge already demonstrates the TFV-specific lateral-flow immunochemical components, Sevenler demonstrates competitive TFV/TFV-DP immunochemistry in blood-cell lysate and expressly anticipates lateral-flow translation, King experimentally establishes greater than 96% conversion of TFV-DP to TFV with acid phosphatase, and Inoue demonstrates that phosphatase digestion can be performed successfully on a blood hemolysate and driven to completion before downstream detection. The modification therefore would have involved applying expressly taught and experimentally validated techniques for their known functions, with predictable production of TFV from TFV-DP followed by detection using Daughtridge’s existing TFV-specific lateral-flow assay.
Regarding claim 26, refer to the discussion above and here. Claim 26 differs materially in its positive-read competitive arrangement, which Daughtridge teaches. Regarding limitation (d), wherein the membrane comprises a tenofovir derivative conjugate bound to the membrane upstream of a second reagent bound to the membrane to form a test line, Daughtridge expressly teaches a positive-read competitive lateral-flow embodiment wherein the test device is a competitive immunoassay utilizing a lateral flow format with a positive read out that measures a single drug substance. Daughtridge teaches that the lateral flow strip has a sample pad that contains the buffering and sample treatment materials, that the sample pad contacts a conjugate pad that contains a label that is linked to an antibody made to the drug substance, and that the conjugate pad contacts a solid support, such as nitrocellulose, that has had a derivative of the target drug striped onto it at a position that is not visible to the user and a binding partner for the conjugate not related to the drug at the test line (ex Avidin/Biotin) (p. 50). Thus, Daughtridge teaches the claimed spatial arrangement of an immobilized drug derivative upstream of a separate second reagent forming the visible test line.
Regarding limitation (d)(i), wherein, if tenofovir is absent, the labeled first reagent is allowed to bind the tenofovir derivative without binding the second reagent, Daughtridge’s positive-read configuration expressly places a label that is linked to an antibody made to the drug substance on the conjugate pad and a derivative of the target drug on the solid support at a position that is not visible to the user, with a separate binding partner for the conjugate at the test line. Thus, in the disclosed positive-read configuration, the target-drug derivative is positioned upstream of the test-line binding partner such that the labeled antibody encounters the target-drug derivative before reaching the test line. (p. 50).
Regarding limitation (d)(ii), wherein, if tenofovir is present, the labeled first reagent-TFV complex flows past the tenofovir derivative conjugated to a carrier and forms a labeled first reagent-second reagent complex at the test line, Daughtridge’s same positive-read embodiment teaches the upstream derivative of the target drug and a downstream binding partner for the conjugate not related to the drug at the test line (ex Avidin/Biotin) (p. 50). Daughtridge further teaches generally that the presence of free drug competitively inhibits binding between the drug-specific antibody and drug derivative (p. 18). Consequently, when TFV occupies the labeled anti-TFV first reagent, the labeled complex passes the upstream immobilized TFV derivative and reaches the downstream binding partner/test line, producing the positive-read test-line complex.
Regarding limitation (e), wherein detecting the labeled first reagent-second reagent complex at the test line provides a detectable signal indicating the presence of TFV-DP, Daughtridge characterizes this embodiment as having a positive read out (p. 50) and explains that the presence of a line in the test zone and the control zone would indicate that the subject had been routinely taking the target drug and the absence of a line would indicate that they had not been taking the drug (pp. 50–51). Thus, Daughtridge expressly teaches that formation of the visible test-line signal in this configuration indicates the presence of the target drug.
Regarding claim 27, Daughtridge teaches that the fluid sample is urine (p. 13). Daughtridge further teaches that the sample is whole blood, plasma, serum, or saliva (p. 30). Regarding the limitation wherein the individual has been prescribed or administered tenofovir or a prodrug thereof, Daughtridge teaches assessing the level of adherence to a prescribed treatment plan for a patient prescribed an NRTI and assessing the NRTI level in a biological fluid sample from an individual who has previously taken an NRTI (p. 30). Daughtridge further teaches that the NRTI is selected from the group consisting of TDF, FTC, and TAF, or derivatives thereof or combinations thereof (p. 13). Accordingly, Daughtridge teaches an individual prescribed or administered the tenofovir prodrugs TDF or TAF.
Regarding claims 28 and 29, Daughtridge teaches antibodies that specifically bind to tenofovir or the tenofovir moiety of tenofovir derivatives (p. 42-43). Daughtridge then states that polyclonal and monoclonal antibodies have been developed for detecting metabolites of the tenofovir-derivative NRTIs and provides the amino acid sequences of the monoclonal antibodies in Table 1 (p. 43). Regarding alternative (a), Daughtridge’s Table 1 expressly identifies antibody 237L as comprising CDR1 QASQSIGNYCS (SEQ ID NO: 17), CDR2 LASNLAS (SEQ ID NO: 25), and CDR3 QSNYWTTSVNYGP (SEQ ID NO: 33), and antibody 237H as comprising CDR1 IDLNRYSVG (SEQ ID NO: 18), CDR2 YIYRTGTTWYANWV (SEQ ID NO: 26), and CDR3 TGTSIATDI (SEQ ID NO: 34) (Table 1, p. 44). Regarding alternative (b), Daughtridge’s Table 1 expressly identifies antibody 145L as comprising CDR1 QSSQNVYKDNYLA (SEQ ID NO: 19), CDR2 YASTLAS (SEQ ID NO: 27), and CDR3 AGAYDCRSGDCRA (SEQ ID NO: 35), and antibody 145H as comprising CDR1 FSLSSYNMQ (SEQ ID NO: 20), CDR2 YIFSTGFTYYASWA (SEQ ID NO: 28), and CDR3 GSTAKGDRDI (SEQ ID NO: 36) (Table 1, p. 44). Regarding alternative (c), Daughtridge’s Table 1 expressly identifies antibody 33L as comprising CDR1 QASQSISSYLN (SEQ ID NO: 21), CDR2 RASN LRS (SEQ ID NO: 29), and CDR3 QSNYYSRSTNYVVP (SEQ ID NO: 37), and antibody 33H as comprising CDR1 FSLSSSSMG (SEQ ID NO: 22), CDR2 YIYASGSGRYYASWANG (SEQ ID NO: 30), and CDR3 VTSNGDNNI (SEQ ID NO: 38) (Table 1, p. 45). Regarding alternative (e), Daughtridge’s Table 1 expressly identifies MHC 2900LC as comprising CDR1 RSSQSLVHSNGNTYLH (SEQ ID NO: 23), CDR2 KVSNRFS (SEQ ID NO: 31), and CDR3 SQGTHVPLT (SEQ ID NO: 39), and MHC 2900HC as comprising CDR1 GFTFTDY (SEQ ID NO: 24), CDR2 RNKAKGYT (SEQ ID NO: 32), and CDR3 EALPY (SEQ ID NO: 40) (Table 1, pp. 46-47).
Regarding claim 30, Daughtridge teaches that the antibody comprises a variable light chain amino acid sequence as set forth in SEQ ID NOs: 11, 13, 15, or 41 (p. 2). Daughtridge further identifies the MHC 2900LC antibody in Table 1 as comprising the variable light -chain region DVVMTQTPLSLPVSLGDQASISCRSSQSLVHSNGNTYLHWYLQKPGQSPKLLIYKVSNRFSGVPDRFSGSGSGTDFTLKISRVEAEDLGVYFCSQGTHVPLTFGAGTKLELK (SEQ ID NO: 41) (Table 1, p. 46). Regarding the limitation wherein the antibody comprises an immunoglobulin variable heavy chain region according to SEQ ID NO: 42, Daughtridge teaches that the antibody comprises a variable heavy chain amino acid sequence as set forth in SEQ ID NOs: 12, 14, 16, or 42 (p. 2). Daughtridge further identifies the corresponding MHC 2900HC antibody in Table 1 as comprising its variable heavy-chain region designated SEQ ID NO: 42, together with the MHC 2900 heavy-chain CDRs (Table 1, p. 47).
Regarding claim 31, King expressly teaches acid phosphatase type XA from sweet potato among the reagents used for determining TFV-DP (Experimental, p. 148). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the phosphatase treatment of the method of claim 25 by employing the acid phosphatase type XA from sweet potato taught by King, because King expressly uses that phosphatase for the same purpose required by the claim—dephosphorylating TFV-DP to TFV. One of ordinary skill would have had a reasonable expectation of success because King experimentally demonstrates that the sweet-potato acid phosphatase treatment converted greater than 96% of TFV-DP to TFV.
Regarding claim 32, Daughtridge expressly teaches that lateral flow immunoassays utilize strips of a membrane, preferably a cellulose membrane such as nitrocellulose, as the solid support for the immunoassay (p. 48). Daughtridge further teaches, with respect to the migration membrane of the lateral flow device, that the types of membranes useful in a lateral flow device include but are not limited to nitrocellulose (including pure nitrocellulose and modified nitrocellulose) and nitrocellulose direct cast on polyester support (p. 67).
Regarding claim 33, Daughtridge expressly teaches that the membrane further comprises a third reagent bound to the membrane downstream or upstream of the test line to form a control line (p. 12).
Regarding claim 34, Daughtridge expressly teaches that the third reagent binds to the first reagent to cause a detectable signal at the control line, wherein the presence of the detectable signal at the control line indicates proper performance of the lateral flow assay (p. 12). Because the first reagent in the applied lateral-flow embodiment is the detectably labeled first reagent, this disclosure teaches binding of the third reagent to the labeled first reagent.
Regarding claim 35, Daughtridge expressly teaches the claimed sample-pad materials. In particular, Daughtridge teaches that the sample pad is a component of a lateral flow device that initially receives the sample, and that among the various materials that may be used to construct a sample pad (such as glass fiber, woven fibers, screen, non-woven fibers, cellosic fibers or paper) (p. 67).
Regarding claim 36, Daughtridge expressly teaches that the second reagent is any of the aforementioned compounds, or a conjugated derivative of the same (p. 10). Daughtridge further defines NRTI-derivative conjugate and NRTI-analog conjugate as NRTI derivatives conjugated to carrier proteins (such as KLH, BSA, etc.) and further expressly teaches that the NRTI-derivative conjugate is a TFV-derivative conjugate (p. 21). Thus, Daughtridge teaches a TFV-derivative second reagent conjugated to a carrier protein. Also, Daughtridge expressly identifies bovine serum albumin (BSA) as a carrier protein and further teaches in certain embodiments, the carrier protein is BSA (p. 37).
Regarding claim 47, refer to the discussion above and here. Claim 47 likewise repeats the phosphatase conversion, sample pad, conjugated label pad, first and second interfaces, membrane, and lateral-flow limitations addressed above with respect to claim 25. The material distinction is the orientation of the competitive reagents and the resulting negative-read operation.
Regarding limitation (b), to the extent claim 47 requires the conjugated label pad to comprise a labeled first reagent without requiring that first reagent to be the anti-TFV antibody recited by claim 25, Daughtridge expressly teaches, for its negative-read competitive lateral-flow embodiment, that the sample pad is in contact with a conjugate pad that contains a label linked to a derivative of the drug substance (p. 49). Thus, Daughtridge teaches the labeled drug-derivative first reagent required by the competitive arrangement of claim 47.
Regarding limitation (c), wherein the membrane comprises a second reagent bound to the membrane to form a test line and the second reagent is specific for tenofovir, Daughtridge expressly teaches that its negative-read lateral-flow embodiment has a solid support, such as nitrocellulose, that has had an antibody striped onto it (p. 49). Daughtridge further specifically teaches antibodies that specifically bind to tenofovir or the tenofovir moiety of tenofovir derivatives (p. 42), and teaches lateral-flow membranes containing reagent lines comprising an anti-NRTI derivative conjugate antibody, such as an anti-TFV derivative conjugate or anti-TFV antibody (pp. 48–49). Accordingly, Daughtridge teaches an immobilized anti-TFV second reagent forming the test line.
Regarding limitation (c)(i), wherein, if tenofovir is present, tenofovir is allowed to bind to the second reagent, Daughtridge teaches that its immobilized anti-TFV antibody specifically binds TFV and further explains the competitive principle that if an antibody is specific for a metabolite (e.g., NRTI), then the presence of the metabolite in a reaction containing labeled NRTI derivative and the antibody will reduce the amount of labeled NRTI derivative bound to the antibody (p. 18). Thus, when TFV is present, free TFV binds the immobilized anti-TFV second reagent and competitively prevents or reduces binding of the labeled TFV-derivative first reagent.
Regarding limitation (c)(ii), wherein, if tenofovir is absent, the labeled first reagent binds the second reagent to form a labeled first reagent-second reagent complex at the test line, Daughtridge expressly teaches the negative-read configuration comprising a conjugate pad that contains a label linked to a derivative of the drug substance and a downstream solid support that has had an antibody striped onto it (p. 49). In the absence of competing free TFV, the labeled TFV derivative therefore binds the immobilized anti-TFV antibody at the test line, forming the claimed labeled first reagent-second reagent complex.
Regarding limitation (d), wherein detecting the detectable label associated with the labeled first reagent-second reagent complex at the test line provides a detectable signal indicating the absence of TFV-DP, Daughtridge expressly teaches that smaller molecules may be detected in a competitive format where only one antibody or binding partner is utilized to detect the drug of interest and that the assay can provide a negative read, in which the line disappears when the drug is present (p. 49). Daughtridge’s negative-read embodiment consequently produces a test-line signal when the target drug is absent and a diminished or absent test-line signal when target drug is present.
Conclusion
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/E.O./Examiner, Art Unit 1677
/BAO-THUY L NGUYEN/Supervisory Patent Examiner, Art Unit 1677 August 19, 2026
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