Obviousness

Obviousness Analysis of U.S. Patent 11,566,277

This analysis assesses the validity of the claims of U.S. Patent 11,566,277 ("the '277 patent") under 35 U.S.C. § 103, focusing on whether the invention would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention.

A PHOSITA in this field circa 2011-2012 would typically have a Ph.D. in molecular biology, biochemistry, or a related field, with several years of postdoctoral or industry experience in areas such as nucleic acid chemistry, immunology, microscopy, and next-generation sequencing (NGS) technologies.

The central argument is that the claims of the '277 patent are rendered obvious by the combination of prior art teaching multiplexed analyte detection using nucleic acid barcodes with well-established methods for cyclic, sequential nucleic acid detection, such as sequencing-by-hybridization or sequencing-by-synthesis.

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Primary Obviousness Combination

A compelling case for obviousness can be made by combining the teachings of:

1. U.S. Pat. No. 7,473,767 to Geiss et al. ("Geiss" or "Nanostring"), which teaches the use of analyte-specific probes conjugated to nucleic acid barcodes for multiplexed detection.
2. The well-established principles and methods of cyclic sequencing-by-hybridization (SBH) or sequencing-by-synthesis (SBS), which were foundational to the field of next-generation sequencing long before the '277 patent's priority date.

1. Teachings of the Prior Art

• Geiss (Nanostring): Geiss discloses a system for detecting and quantifying numerous target molecules (analytes) simultaneously. The core of the Nanostring system is a "reporter probe" (a detection reagent) comprising a target-specific probe attached to a single-stranded DNA molecule. This DNA molecule is functionalized with a series of different fluorescent labels, creating a color-coded "barcode." The identity of the target analyte is determined by reading the spatial order of the colors along this barcode using high-resolution imaging. Geiss thus teaches the fundamental structure of the '277 patent's detection reagent: a probe conjugated to a nucleic acid label that serves as an identifier.

• Cyclic Sequencing (SBH/SBS): By 2011, cyclic sequencing methods were mature and widely practiced. These methods, which form the basis of platforms like those from Illumina and Applied Biosystems (SOLiD), operate on a core principle of sequential, iterative steps:

  1. Step 1 (Hybridization/Incorporation): A labeled oligonucleotide (in SBH) or a labeled nucleotide (in SBS) is introduced and binds to its complementary sequence.
  2. Step 2 (Imaging): The entire sample or flow cell is imaged to detect the signal (e.g., fluorescence) from the successfully bound molecule. This captures the identity of one position in the sequence.
  3. Step 3 (Signal Removal): The signal is removed, either by cleaving the fluorescent label or by stripping away the labeled oligonucleotide with a chemical wash or heat.
  4. Step 4 (Repeat): The cycle is repeated with a new set of labeled molecules to read the next position in the sequence.

  This process generates a temporal sequence of signals (e.g., Color 1 in cycle 1, Color 2 in cycle 2, etc.) for each nucleic acid molecule being sequenced. This is the exact process described in the '277 patent as "detecting in a temporally-sequential manner."

2. Motivation to Combine

A PHOSITA would have been motivated to combine the Nanostring reporter probe concept with the cyclic sequencing readout method to overcome a well-understood limitation of the Nanostring approach.

The primary motivation is to improve scalability and throughput while reducing instrument complexity.

The spatial decoding method of Geiss requires extremely high-magnification optics to resolve multiple distinct colors on a single molecule that is only nanometers long. This physical constraint limits the field of view, meaning only a small area of a sample can be analyzed at once, and it increases the cost and complexity of the imaging hardware.

A PHOSITA, being intimately familiar with the massive scalability of cyclic sequencing, would have recognized that applying this temporal readout method to the Nanostring barcodes was an obvious solution. Instead of trying to resolve all the colors at once in space, it would be a predictable and logical step to treat the barcode as a short sequence to be read one "base" (or subsequence) at a time using the established cyclic SBH/SBS workflow.

This combination would allow for the use of lower-magnification, wider-field-of-view optics, as the system would only need to detect a single color at a specific location in each cycle. The identity is derived from the sequence of colors over time at that location, not the arrangement of colors in space. This would directly lead to higher throughput, lower cost, and the ability to analyze larger samples, such as entire tissue sections, more efficiently.

3. Application to the Claims

This combination of Geiss and the principles of cyclic sequencing renders the independent claims of the '277 patent obvious.

• Claim 1 (Method):

  • contacting the sample with a plurality of detection reagents...: Taught by Geiss.
  • each detection reagent comprises at least one probe reagent and at least one nucleic acid label: This is precisely Geiss's reporter probe structure.
  • said at least one nucleic acid label comprises a plurality of pre-determined subsequences: This is the barcode structure taught by Geiss, where the "subsequences" correspond to the binding sites for the different colored labels.
  • detecting in a temporally-sequential manner... wherein a temporal order of the signal signatures... identifies a subpopulation of the detection reagents: This is the key element not explicitly taught by Geiss, but it is the fundamental and well-known process of cyclic SBH/SBS. The motivation to apply this temporal readout to Geiss's barcodes, as explained above, makes this step obvious.

• Claim 14 (Composition):

  • A detection reagent comprising at least one probe reagent and at least one nucleic acid label...: This composition is taught by Geiss.
  • said at least one nucleic acid label comprises at least one pre-determined subsequence to be detected in a temporally-sequential manner: While Geiss teaches detecting the subsequences spatially, designing a nucleic acid barcode to be read by a known temporal method (cyclic sequencing) would have been an obvious design choice for a PHOSITA motivated to improve scalability. The structure of the molecule itself is not materially different; what changes is the intended method of reading it, which was a well-known alternative.

• Claim 21 (Kit):

  • A kit containing the obvious detection reagents from claim 14 and other reagents (like decoder probes used in SBH) would be obvious to a PHOSITA implementing the obvious method of claim 1. Assembling the necessary components for an obvious process into a kit is a routine and obvious practice in the art.

Conclusion

The core concept claimed in the '277 patent—using a temporal sequence of signals from a nucleic acid barcode to identify an analyte—is not an inventive leap but rather the logical and predictable convergence of two well-established technologies. The prior art taught the use of nucleic acid barcodes for multiplexed detection (Geiss) and separately taught the use of cyclic, temporal detection for reading nucleic acid sequences (SBH/SBS). A person of ordinary skill in the art would have been motivated to combine these teachings to create a more scalable and robust system for multiplexed analysis, directly arriving at the invention claimed in the '277 patent. Therefore, the claims of the '277 patent are invalid as obvious under 35 U.S.C. § 103.