Nikhil Sebastian

Dr. Nikhil Sebastian


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2019 in Radiotherapy and Oncology
Verified
Journal Article
Closed access
NSNikhil Sebastian
Nikhil Sebastian
TWTrudy Wu
Trudy Wu
JBJose Bazan
Jose Bazan
EDErin Driscoll
Erin Driscoll
HWHenning Willers
Henning Willers
TWTerence Williams
Terence Williams

21 January 2023 in Clinical Lung Cancer
Verified
Journal Article
Open access
NSNikhil Sebastian
Nikhil Sebastian
WSWilliam A. Stokes
William A. Stokes
MBMadhusmita Behera
Madhusmita Behera
RJRenjian Jiang
Renjian Jiang
DGDavid A. Gutman
David A. Gutman
DMDrew Moghanaki
Drew Moghanaki
Immune checkpoint inhibitors (ICI) are commonly used in the management of patients with advanced non-small cell lung cancer (NSCLC), but response is suboptimal. Preclinical data suggest ICI efficacy may be enhanced with concomitant nonsteroidal anti-inflammatory (NSAID) medications. In this retrospective study, the Veterans Health Administration Corporate Data Warehouse was queried for patients diagnosed with NSCLC and treated with ICI from 2010 to 2018. Concomitant NSAID use was defined as NSAID dispensation by a VA pharmacy within 90 days of the any ICI infusion. To mitigate immortal time bias, patients who started NSAIDs 60 or more days after ICI initiation were excluded from analysis. Survival was measured from start of ICI. We identified 3634 patients with NSCLC receiving ICI; 2336 (64.3%) were exposed to concomitant NSAIDs. On multivariable analysis, NSAIDs were associated with better overall survival (HR = 0.90; 95% CI, 0.83-0.98; P = .010). When stratifying by NSAID type, diclofenac was the only NSAID with significant association with overall survival (HR = 0.75; 95% CI, 0.68-0.83; P < .001). Propensity score matching of the original cohort yielded 1251 patients per cohort balanced in characteristics. NSAIDs remained associated with improved overall survival (HR = 0.85; 95% CI, 0.78-0.92; P < .001). This study of Veterans with NSCLC treated with ICI demonstrated that concomitant NSAIDs are associated with longer OS. This may indicate that NSAIDs can enhance ICI-induced antitumor immunity and should prospectively validated.

7 January 2020 in Colorectal Disease
Verified
Journal Article
Closed access
PDF file
NSNikhil Sebastian
Nikhil Sebastian
YTYubo Tan
Yubo Tan
EMEric Miller
Eric Miller
TWTerence M. Williams
Terence M. Williams
DDDayssy Alexandra Diaz
Dayssy Alexandra Diaz

4 March 2025 in Cancer
Verified
Journal Article
Closed access
NSNikhil Sebastian
Nikhil Sebastian
DPDattatraya Patil
Dattatraya Patil
PPPretesh R. Patel
Pretesh R. Patel
AJAshesh B. Jani
Ashesh B. Jani
BHBruce W. Hershatter
Bruce W. Hershatter
SPSagar A. Patel
Sagar A. Patel

24 May 2022 in Cancer Medicine
Verified
Journal Article
Open access
WSWilliam A. Stokes
William A. Stokes
MBMadhusmita Behera
Madhusmita Behera
RJRenjian Jiang
Renjian Jiang
DGDavid A. Gutman
David A. Gutman
ZHZhonglu Huang
Zhonglu Huang
DMDrew Moghanaki
Drew Moghanaki
Background: Peroxisome proliferator‐activated receptor agonists such as fibrates restore oxidative metabolism in cytotoxic T‐lymphocytes, thereby enhancing response to immune checkpoint inhibitors (ICI) in preclinical models. However, there is no evidence in humans on the clinical impact of fibrates as an adjunct to ICI.Methods: In this cohort study of Veterans with non‐small cell lung cancer (NSCLC) receiving ICI, fibrate exposure was defined as a prescription filled within 90 days of an ICI infusion. Overall survival (OS), measured from the start of ICI, was compared between exposed and unexposed Veterans. Cox multivariable analysis (MVA) was used to identify factors associated with OS. A sensitivity analysis of Veterans with stage IV NSCLC who received docetaxel without ICI was similarly performed.Results: The ICI cohort included 3593 Veterans, of whom 301 (8.5%) coincidentally received a fibrate. Veterans receiving fibrates were more likely to be older, white, male, and married, and to have greater comorbidity burden, but less likely to receive chemotherapy. Coincidental fibrates were associated with improved OS both on MVA (HR 0.86, 95%CI 0.75–0.99) and in a matched subset (HR 0.75, 95%CI 0.63–0.90). In contrast, among the cohort of 968 Veterans treated with chemotherapy, fibrates did not have a significant impact on OS by MVA (HR 0.99, 95%CI 0.79–1.25) or in a matched subset (HR 1.02, 95%CI CI 0.75–1.39).Conclusions: Concomitant fibrates are associated with improved OS among NSCLC patients receiving ICI but not among those receiving chemotherapy. This hypothesis‐generating observation supports a potential role for fibrates as an adjunct to immunotherapy.

10 August 2023 in Cancer
Verified
Journal Article
Open access
NSNikhil Sebastian
Nikhil Sebastian
AWAmy Webb
Amy Webb
KSKonstantin Shilo
Konstantin Shilo
RRRyan Robb
Ryan Robb
MXMeng Xu‐Welliver
Meng Xu‐Welliver
TWTerence M. Williams
Terence M. Williams
Introduction: Increasingly, early‐stage non–small cell lung cancer (NSCLC) is treated with stereotactic body radiation therapy (SBRT). Although treatment is generally effective, a small subset of tumors will recur because of radioresistance. Preclinical studies suggested PI3K‐AKT‐mTOR activation mediates radioresistance. This study sought to validate this finding in tumor samples from patients who underwent SBRT for NSCLC.Methods: Patients with T1‐3N0 NSCLC treated with SBRT at our institution were included. Total RNA of formalin‐fixed paraffin‐embedded tumor biopsy specimens (pretherapy) was isolated and analyzed using the Clariom D assay. Risk scores from a PI3K activity signature and four published NSCLC signatures were generated and dichotomized by the median. Kaplan–Meier curves and Cox regressions were used to analyze their association with recurrence and overall survival (OS). The PI3K signature was also tested in a data set of resected NSCLC for additional validation.Results: A total of 92 patients were included, with a median follow‐up of 18.3 months for living patients. There was no association of any of the four published gene expression signatures with recurrence or OS. However, high PI3K risk score was associated with higher local recurrence (hazard ratio [HR], 11.72; 95% CI, 1.40–98.0; p = .023) and worse disease‐free survival (DFS) (HR, 3.98; 95% CI, 1.57–10.09; p = .0035), but not OS (p = .49), regional recurrence (p = .15), or distant recurrence (p = .85). In the resected NSCLC data set (n = 361), high PI3K risk score was associated with decreased OS (log‐rank p = .013) but not DFS (p = 0.54).Conclusions: This study validates that higher PI3K activity, measured by gene expression, is associated with local recurrence and worse DFS in early‐stage NSCLC patients treated with SBRT. This may be useful in prognostication and/or tailoring treatment, and merits further validation.