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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 01/16/2026 has been entered.
Claims 1-6 and 8-12 are pending in this application, Claims 8-11 are acknowledged as withdrawn, Claims 1-6 and 12 were examined on their merits.
Claim Objections
Claim 12 is objected to because of the following informalities: The phrase “to the fluid” is repeated in the claim. Appropriate correction is required.
Claim Rejections - 35 USC § 103
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.
Claims 1 and 12 are rejected under 35 U.S.C. § 103 as being unpatentable
over Gibbings et al. (US 2019/0093105 A1) and Konoshenko et al. (2018), Pall (2003) and Benedikter et al. (2017), all of record.
Gibbings et al. teaches a method for isolating exosomes from a culture media (a
biofluid, giving the term its’ broadest reasonable interpretation) comprising enrichment
(increasing the concentration thereof) by tangential flow filtration (TFF) or centrifugal
filtration to eliminate cells, larger vesicles and debris then concentrating by TFF or other
filtration methods or by (immuno)affinity purification using antibodies coupled to beads;
and wherein the ordinary artisan could select a suitable collection or enriching technique
(Pg. 7, Paragraph [0105]).
Gibbings et al. does not teach the required number (3) of isolation methods (e.g.
tangential flow filtration, centrifugal filtration and immunomagnetic affinity), the specific
order of process steps; adding a buffer solution to the biofluid and performing TFF after
the addition, then transferring the biofluid to a centrifugal filtration unit, wherein the
centrifugal filtration unit includes a membrane having a 10 kDa molecular weight cutoff,
applying centrifugal force to the biofluid in the centrifugal filter unit and capturing
extracellular vesicles (EV) in the membrane, then transferring the captured EVs to an
immunomagnetic affinity container with a plurality of magnetic beads, wherein the beads
are magnetic and removing the magnetic beads and eluting/separating the EVs
therefrom or wherein the isolated target extracellular vesicles (EV) includes at least 95% of the EVs from the biofluid sample, as required by Claim 1;
or wherein the centrifugal force is applied at no greater than 3,000g to the biofluid in the centrifugal filtration unit, as required by Claim 12.
Benedikter et al. teaches the isolation of EVs/exosomes using centrifugal
filtration units with a 10 kDa molecular weight cutoff, applying centrifugal force of 4000 g to the biofluid in the centrifugal filter unit and capturing extracellular vesicles (EV) in the
membrane (Pg. 10, Lines 40-43).
Pall teaches that TFF involves concentration (Pg. 3, Column 2, Lines 7-29) and
diafiltration, wherein in continuous diafiltration water or buffer is added to the sample
feed (e.g. biofluid) reservoir at the same rate as filtrate is generated keeping volume in
the sample reservoir constant (Pg. 4, Column 1, Lines 1-18)
Konoshenko et al. teaches the use of magnetic beads with antibodies to isolate
exosomes from a liquid and separating the exosomes from the magnetic beads by
elution (Pg. 18, Column 1, Lines 52-59).
It would have been obvious to those of ordinary skill in the art before the effective
filing date of the claimed invention to modify the exosome isolation method of Gibbings
et al. so that a step of tangential flow filtration is performed on an exosome containing
biofluid, wherein buffer is added to the sample reservoir (thus to the biofluid) during
TFF, as taught by Pall, followed by a step of centrifugal filtration at 4000g using centrifugal filtration units with a 10 kDa molecular weight cutoff, applying centrifugal force to the biofluid in the centrifugal filter unit and capturing extracellular vesicles (EV) in the membrane, as taught by Benedikter et al., followed by affinity purification because the reference teaches these are suitable means for purifying and isolating exosomes and it would have been obvious to combine them all into a single method for the same
purpose. Further, the selection of any order of performing process steps is prima facie
obvious in the absence of new or unexpected results. See the MPEP at 2144.04, IV.,
C. Those of ordinary skill in the art would have been motivated to make this
modification in order to have the purest, isolated exosomes from a sample. There would have been a reasonable expectation of success in making this modification because Gibbings et al. already teaches that exosomes can be isolated using centrifugal filtration, TFF and affinity purification, and a sequential performance of
at least two of the methods.
It would have been further obvious to those of ordinary skill in the art before the
effective filing date of the claimed invention to modify the exosome isolation method of
Gibbings et al., Pall and Benedikter et al. to further utilize beads which are magnetic
and removing the magnetic beads from the biofluid and eluting the exosomes therefrom,
as taught by Konoshenko et al. because Gibbings et al. is generally drawn to affinity
purification of exosomes by bead-bound antibodies and Konoshenko et al. provides a
specific type of bead suitable for exosome isolation. Those of ordinary skill in the art
would have been motivated to make this modification in order to further isolate desired
exosomes from a liquid. There would have been a reasonable expectation of success
in making this modification because at least Gibbings et al. is drawn to the use of affinity
purification to isolate exosomes and Konoshenko et al. teaches that magnetic affinity
purification is suitable for exosome purification.
With regard to Claim 1, it would have been further obvious to those of ordinary skill in the art before the instant invention to isolate target EVs to include at least 95% of the EVs from the sample because while the Gibbings et al. reference is silent with regard to the percent purity of EVs isolated from the biofluid concentration of the DNAse in the composition, the determination of the optimal percent purity of EVs isolated by the method by routine experimentation and optimization of result effective variables is not inventive. In this instance, the concentration of EVs isolated from the biofluid will directly correlate with the percentage of EVs isolated from the sample. That is, a more efficient EV isolation method will isolate a higher percentage of EVs available from the biofluid.
Those of ordinary skill in the art before the effective filing date on the instant invention would have been motivated to make this modification in order to obtain the highest percentage of the desired EVs from the initial biofluid. There would have been a reasonable expectation of success in making this modification because the Gibbings et al. reference already provides a method for isolating exosomes from a culture media/biofluid and the determination of result effective variables by routine optimization and experimentation is within the purview of those of ordinary skill in the art. Absent any teaching of criticality by the Applicant concerning the percentage of EVs isolated from the biofluid, it would be prima facie obvious that one of ordinary skill in the art would recognize this limitation as an optimizable variable which can be met as a matter of routine optimization (see MPEP § 2144.05 (II)(B). Those of ordinary skill in the art before the effective filing date of the claimed invention would have been motivated to make this modification in order to obtain the highest amount of desired EVs from the initial biofluid. There would have been a reasonable expectation of success in making these modifications because Gibbings et al. is drawn to a method for isolating desired EVs (exosomes) from a biological fluid.
While the references listed above do not specifically teach the limitation of Claim 12, that the centrifugal force applied to the biofluid in the centrifugal filtration unit at not more than 3,000g, one of ordinary skill in the art would recognize that the selection of centrifugation speed for a centrifugal filtration unit to isolate exosomes from a biofluid is a result-effective optimizable variable.
Benedikter et al. teaches the isolation of EVs/exosomes using centrifugal filtration units with a 10 kDa molecular weight cutoff, applying centrifugal force of 4000 g to the biofluid in the centrifugal filter unit and capturing extracellular vesicles (EV) in the membrane (Pg. 10, Lines 40-43). This is a general teaching utilizing a similar method and centrifuge speed as claimed. This is motivation for someone of ordinary skill in the art to practice or test the centrifugation speeds widely to find those that are functional or optimal to isolate EVs from a biofluid which then would be inclusive or cover the instantly claimed range. Absent any teaching of criticality by the Applicant concerning the centrifugation speed, it would be prima facie obvious that one of ordinary skill in the art would recognize this limitation as an optimizable variable which can be met as a matter of routine optimization (see MPEP § 2144.05 (II)(B). Those of ordinary skill in the art before the effective filing date of the claimed invention would have been motivated to make this modification in order to obtain the desired EVs. There would have been a reasonable expectation of success in making these modifications because Benedikter et al. teaches the isolation of EVs/exosomes using centrifugal filtration units at a similar centrifugation speed.
With regard to Claim 7, Gibbings et al. teaches enrichment (concentration) of
exosomes in a biofluid by TFF, the finding as obvious the use of an additional
centrifugal filtration step, and the use of an immunoaffinity bead isolation step.
Konoshenko et al. teaches the isolation of exosomes using magnetic immunoaffinity
beads.
Thus, as the prior art performs the same method steps as claimed, the ordinary
artisan would expect a similar result as claimed with respect to the percentage of
isolated exosomes from the biofluid sample.
Claims 1, 2, 3, 4, 5, 6 and 12 are rejected under 35 U.S.C. § 103 as being
unpatentable over Gibbings et al. (US 2019/0093105 A1) and Konoshenko et al. (2018), Pall (2003) and Benedikter et al. (2017), as applied to Claims 1 and 12 above, and further in view of Vlassov et al. (EP 3327440 A1), all of record.
The teachings of Gibbings et al., Pall, Benedikter et al. and Konoshenko et al.
were discussed above.
None of the above references taught a method wherein the biofluid is blood, as
required by Claim 2;
wherein the biofluid is urine, as required by Claim 3;
wherein the biofluid is serum, as required by Claim 4;
wherein the biofluid is plasma, as required by Claim 5;
or wherein the biofluid is CSF, as required by Claim 6.
Vlassov et al. teaches that exosomes may be isolated from biological fluids (Pg.
2, Paragraph [0007]] wherein the biological fluid may be: culture media, serum, plasma,
blood, urine or CSF (Pg. 3, Paragraph [0013]).
It would have been obvious to those of ordinary skill in the art to modify the
method of Gibbings et al., Pall, Benedikter et al. and Konoshenko et al. of isolating
exosomes from culture media to apply the method to other biofluids such as taught by
Vlassov et al. because all of the samples are art-recognized sources of exosomes. See
the MPEP at 2144.06, I. Those of ordinary skill in the art would have been motivated to
make this modification due to the desire to isolate exosomes from a particular biofluid of
interest. There would have been a reasonable expectation of success in making this
modification because all of the biofluids are art-recognized equivalent sources from
which exosomes may be isolated.
Response to Arguments
Applicant's arguments filed 01/16/2026 have been fully considered but they are not persuasive.
The Applicant argues that each of the cited references teaches different methodologies for separating, filtering or purifying a sample using different sample types, scales and technical goals and there is no teaching, suggestion or motivation to combine the methods in the specific sequence as claimed (Remarks, Pg. 6, Lines 22-26 and Pg. 7, Lines 1-2).
This is not found to be persuasive for the reasoning provided in the above rejections, that is, while no singular reference teaches all of the claimed elements, each reference when considered as a whole makes obvious the claimed invention.
The Applicant argues that the order of performance of the steps is critical because each concentrates and purifies EVs before their isolation. Applicant argues that each step is not interchangeable and the order is not irrelevant citing Konoshenko, whom allegedly teaches that different isolation methods yield different EV populations and that combining methods may compromise yield or purity. Applicant notes that Pall suggests that centrifugation is not needed after TFF because a higher concentration in less time can be achieved with centrifugal devices. Applicant concludes that there is no reasonable expectation of success that combining the references would yield the claimed percentage isolation (Remarks, Pg. 7, Lines 4-16).
The fact that each step purifies and concentrates EVs prior to their isolation is not evidence of criticality. Konoshenko was citing only for its' teaching of the use of magnetic beads with antibodies to isolate exosomes and then eluting the exosomes from the beads. The Examiner further notes MPEP 2144.04, IV. C citing In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946) (selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results) and In re Gibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930) (Selection of any order of mixing ingredients is prima facie obvious.).
While Konoshenko “may” generally teach that different isolation methods yield different EV populations and combining methods “may” compromise yield or purity, this is not a specific teaching away from combining isolation techniques. Pall merely generally teaches that TFF can achieve higher concentrations in less time than with centrifugal devices or stirred cells, this is not a specific teaching away from performing centrifugation after TFF in the purification/isolation of exosomes/EVs.
The Applicant argues that In re Burhans only applies where the prior art teaches all of the steps and their combination and where rearrangement would be expected to work for the same purpose. Applicant opines that the cited prior art does not teach or suggest the claimed combination or sequence or that order is irrelevant. Applicant notes that the Examiner must provide a logical rationale as to why the ordinary artisan would combine the steps the claimed order. Applicant finally alleges improper hindsight (Remarks, Pg. 7, Lines 17-28 and Pg. 8, Lines 1-2).
This is not found to be persuasive for the following reasons, in response to Applicant's argument that the Examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
As discussed above and in the prior action, Gibbings et al. teaches at least a two-step method of isolating exosomes and teaches multiple techniques to do so. It would have been obvious to those of ordinary skill in the art therefore to modify the exosome isolation method of Gibbings so that a step of tangential flow filtration is performed on an exosome containing biofluid, wherein buffer is added to the sample reservoir (thus to the biofluid) during TFF, as taught by Pall, followed by a step of centrifugal filtration using centrifugal filtration units with a 10 kDa molecular weight cutoff, applying centrifugal force to the biofluid in the centrifugal filter unit and capturing extracellular vesicles (EV) in the membrane, as taught by Benedikter et al., followed by affinity purification because Gibbings teaches these are all suitable means for purifying and isolating exosomes and it would have been obvious to combine them all into a single method for the same purpose. Further, the selection of any order of performing the process steps is prima facie obvious in the absence of new or unexpected results. See the MPEP at 2144.04, IV., C. Konoshenko was citing only for its' teaching of the use of magnetic beads with antibodies to isolate exosomes and then eluting the exosomes from the beads. The Examiner further notes MPEP 2144.04, IV. C cites In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946) (selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results) and In re Gibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930) (Selection of any order of mixing ingredients is prima facie obvious.). The Examiner notes that Applicant has provided no evidence on the record of the criticality of the order of performing the claimed method steps and the Examiner has provided sound, logical rational both above and in the prior action to support the finding of obviousness.
No claims are allowed.
Any inquiry concerning this communication or earlier communications from the Examiner should be directed to PAUL C MARTIN whose telephone number is (571)272-3348. The Examiner can normally be reached Monday-Friday 12pm-8pm EST.
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/PAUL C MARTIN/ Examiner, Art Unit 1653 02/13/2026