Guardant holds on to diagnostics patent following TwinStrand challenge
PTAB says claims of genetic disease testing patent are not obvious | Rival biotech firm denied petition for invalidation.
The US Patent Trial and Appeal Board (PTAB) upheld a diagnostics patent belonging to precision oncology company Guardant Health, determining that a rival biotech firm had failed to show its claims were unpatentable.
Friday’s judgment (January 26) rebuked a challenge to Guardant’s US patent 11,149,306 from Seattle-based TwinStrand Biosciences, which had said claims 1-29 were invalid as obvious.
Judges Hulse and Valek acknowledged the prior art references to the ‘306 patent that formed the basis of TwinStrand’s contention, but were not convinced that they rendered any of the claims obvious.
They denied Guardant’s motions to strike the declarations of certain TwinStrand witnesses, and exclude “newly introduced exhibits” it said were “irrelevant”, but this did not affect their finding that the patent was valid.
Challenge to patent ‘unpersuasive’
The ‘306 patent relates to a method for the early detection and monitoring of genetic diseases, specifically by tagging and counting both halves of double-stranded DNA and estimating the number of unseen molecules.
Following its request for inter partes review of the patent, TwinStrand cited a number of prior art references it said rendered the claims invalid as obvious, including journal articles from 2008 and 2012, and an international patent application from 2013.
However, judges found its arguments unpersuasive having examined the references against independent claims 1 and 17 of the ‘306 patent.
This included that TwinStrand had not “sufficiently shown that any of these references teach or suggest ‘sorting a plurality of sequence reads from the set of sequence reads into (i) families comprising paired reads … and (ii) families comprising unpaired reads’” as recited in claim 17.
They waived a further argument from the biotech that Guardant Health had been given insufficient time to address.
Motions dismissed
During the proceedings, Guardant claimed TwinStrand had “improperly” attempted to substitute its original expert with “replacement witnesses to backfill identified deficiencies” in its petition, as well as introduce new theories.
It also submitted a motion to strike certain exhibits which it said were “newly introduced exhibits that are primarily attempts to backfill content missing from the petition case, irrelevant . . .and/or not properly responsive to argument made in the [response]”.
However, the PTAB sided with TwinStrand on both these matters, accepting its explanation that there had been “scheduling difficulties” with its expert that had prevented him submitting a declaration.
Judges said they had not relied on any of the exhibits objected to by Guardant in their decision, therefore its motion to exclude them was dismissed as moot.
$83.4m payout
In November last year, Guardant Health was ordered to pay $83.4 million in damages for infringing patents related to DNA mutation technology, owned by the University of Washington and licensed to TwinStrand.
This was through the sale of its FDA-approved Guardant360 CDx product, as well as commercial products in cancer screening, detection, and characterisation.
Guardant said it strongly disagreed with the decision and planned to appeal.
Last week’s judgment was a final written decision on the case TwinStrand Biosciences v Guardant Health. TwinStrand was represented by Sterne Kessler and Guardant was represented by Wilson Sonsini.
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