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Image of the PCS web-application at

Patent Citation Spectroscopy (PCS): Online retrieval of landmark patents based on an algorithmic approach

Jordan A. Comins[i],*,‡, Stephanie A. Carmack[ii], and Loet Leydesdorff[iii]

One essential component in the construction of patent landscapes in biomedical research and development (R&D) is identifying the most seminal patents. Hitherto, the identification of seminal patents required subject matter experts within biomedical areas. In this brief communication, we report an analytical method and tool, Patent Citation Spectroscopy (PCS), for the online identification of landmark patents in user-specified areas of biomedical innovation. Using USPTO data and the PatentsView API, PCS mines the cited references within large sets of patents and provides an estimate of the most historically impactful prior work.

The figure shows the results of PCS applied to a broad set of patents dealing with cholesterol. PCS mined through 11,326 cited references and identified the seminal patent as that for Lipitor, the groundbreaking medication for treating high cholesterol as well as the pair of patents underlying Repatha. The cases suggest that PCS provides a useful method for identifying seminal patents in areas of biomedical innovation and therapeutics. The interactive tool is free-to-use at:

Figure: Image of the PCS web-application at In this demo, the user queried patents containing either the key terms “RNAi” or “siRNA” or the phrases “interference RNA” or “RNA interference.” The system then searched the titles and abstracts of US patents within the PatentsView database for these search terms. The result was 1,217 granted US patents containing 4,065 unique patent references. The patent references were analyzed via PCS to produce a visualization of the spectrum of impactful historical patent references. PCS identified the most important historical patent for this field: US6506559 – Genetic inhibition by double-stranded RNA by Fire et al.  (2003), a finding that converges with independent reports from subject matter experts (Schmidt et al., 2007).

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[i] *corresponding author; Social and Behavioral Sciences Department, The MITRE Corporation, McLean, VA, United States;

The author's affiliation with The MITRE Corporation is provided for identification purposes only, and is not intended to convey or imply MITRE's concurrence with, or support for, the positions, opinions or viewpoints expressed by the author. Approved for Public Release; Distribution Unlimited Case #17-0951.

[ii] National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224

[iii] Amsterdam School of Communication Research (ASCoR), University of Amsterdam, PO Box 15793, 1001 NG Amsterdam, The Netherlands

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