Nikolay Conev

Dr. Nikolay Conev

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

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1 November 2019 in The Lancet
Verified
Journal Article
Closed access
LPLuis Paz-Ares
Luis Paz-Ares
MDMikhail Dvorkin
Mikhail Dvorkin
YCYuanbin Chen
Yuanbin Chen
NRNiels Reinmuth
Niels Reinmuth
KHKatsuyuki Hotta
Katsuyuki Hotta
MWMichael Williamson
Michael Williamson

6 October 2023 in Clinical Cancer Research
Verified
Journal Article
Open access
PDF file
LPLuis Paz-Ares
Luis Paz-Ares
MGMarina C. Garassino
Marina C. Garassino
YCYuanbin Chen
Yuanbin Chen
Niels ReinmuthNiels Reinmuth
Niels Reinmuth
KHKatsuyuki Hotta
Katsuyuki Hotta
JGJonathan W. Goldman
Jonathan W. Goldman
Purpose: In the CASPIAN trial, first-line durvalumab plus platinum-etoposide (EP) significantly improved overall survival (OS) versus EP alone in extensive-stage small cell lung cancer (ES-SCLC). We report exploratory analyses of CASPIAN outcomes by programmed cell death ligand-1 (PD-L1) expression and tissue tumor mutational burden (tTMB). Experimental Design: Patients were randomized (1:1:1) to durvalumab (1,500 mg) plus EP, durvalumab plus tremelimumab (75 mg) plus EP, or EP alone. Treatment effects in PD-L1 and tTMB subgroups were estimated using an unstratified Cox proportional hazards model. Results: The PD-L1 and tTMB biomarker-evaluable populations (BEP) comprised 54.4% (438/805) and 35.2% (283/805) of the intention-to-treat population, respectively. PD-L1 prevalence was low: 5.7%, 25.8%, and 28.3% had PD-L1 expression on ≥1% tumor cells (TC), ≥1% immune cells (IC), and ≥1% TCs or ICs, respectively. OS benefit with durvalumab plus EP versus EP was similar across PD-L1 subgroups, with HRs all falling within the 95% confidence interval (CI) for the PD-L1 BEP (0.47‒0.79). OS benefit with durvalumab plus tremelimumab plus EP versus EP was greater in PD-L1 ≥1% versus <1% subgroups, although CIs overlapped. There was no evidence of an interaction between tTMB and treatment effect on OS (durvalumab plus EP vs. EP, P = 0.916; durvalumab plus tremelimumab plus EP vs. EP, P = 0.672). Conclusions: OS benefit with first-line durvalumab plus EP in patients with ES-SCLC was observed regardless of PD-L1 or tTMB status. PD-L1 expression may prove to be a useful biomarker for combined treatment with PD-(L)1 and CTLA-4 inhibition, although this requires confirmation with an independent dataset. See related commentary by Rolfo and Russo, p. 652

29 February 2020 in BioScience Trends
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Journal Article
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MPMila P. Petrova
Mila P. Petrova
MEMariyana I. Eneva
Mariyana I. Eneva
JAJeliazko I. Arabadjiev
Jeliazko I. Arabadjiev
NCNikolay Conev
Nikolay Conev
EDEleonora G. Dimitrova
Eleonora G. Dimitrova
IDIvan S. Donev
Ivan S. Donev
The aim of this multicentric retrospective study is to evaluate the predictive and prognostic performance of neutrophil to lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and their dynamics in patients with non-small cell lung cancer (NSCLC) treated with pembrolizumab as a second line. Patients with metastatic NSCLC (n = 119), whose tumors expressed programmed death-ligand 1 (PD-L1) ≥ 1%, were retrospectively analyzed between Apr 2017 and Apr 2019. All patients received platinum-containing chemotherapy as a first line treatment. Pre-treatment NLR was calculated by dividing the number of neutrophils by the number of lymphocytes in peripheral blood before the first pembrolizumab infusion. Progression free survival (PFS) and overall survival (OS) was compared by Kaplan-Meier method and Cox Proportional Hazard model. Patients with NLR > 5 before immunotherapy showed significantly shorter mean PFS of 6.86 months (95% CI: 5.81-7.90) as compared to those with NLR ≤ 5 of 18.82 months (95% CI: 15.87-21.78) (long rank test p < 0.001). Furthermore in the multivariate analysis, only NLR > 5 was an independent predictive factor for shorter PFS (HR: 4.47, 95% CI: 2.20-9.07, p < 0.001). In multivariate analysis, presence of bone metastases (HR: 2.08, 95% CI: 1.10-4.94, p = 0.030), NLR > 5 before chemotherapy (HR: 8.09, 95% CI: 2.35-27.81, p = 0.001) and high PLR before chemotherapy (HR: 2.81, 95% CI: 1.13-6.97, p = 0.025) were found to be independent negative prognostic factors for poor OS. Our data suggests that NLR ≤ 5 is a potential predictive marker, which may identify patients appropriate for immunotherapy as a second line treatment.

1 January 2015 in BioScience Trends
Verified
Journal Article
Closed access
NCNikolay Conev
Nikolay Conev
IDIvan S. Donev
Ivan S. Donev
AKAssia Konsoulova
Assia Konsoulova
TCTrifon G. Chervenkov
Trifon G. Chervenkov
JKJavor K. Kashlov
Javor K. Kashlov
KIKrasimir D. Ivanov
Krasimir D. Ivanov
The present study examined whether miR-17, miR-21, miR-29a, and miR-92 that are dysregulated in colon cancer (CC) can serve as potential predictive markers for relapse of disease after radical surgery and adjuvant chemotherapy. Real-time reverse transcription quantitative polymerase chain reaction was used to measure the expression levels of the miRNAs in serum samples from 37 patients with CC and 7 healthy individuals, tested as a control group. The area under the receiver operating characteristic curve (AUC) was then used to evaluate the predictive performance of the four miRNAs alone or in combination and compare it with carcinoembryonic antigen. The expression of miR-17, miR-21 and miR-92 were significantly higher in serum of patients with disease relapse. The AUCs for miR-17, miR-21, miR-92 for Nx patients were 0.844, 0.948, and 0.935, respectively (p < 0.05). Combining the four miRNAs for stage III patients increased the diagnostic performance, yielding an AUC of 0.881, with a sensitivity of 83.3% and a specificity of 85.7% (p < 0.05). Our study suggests that the expression levels of serum miR-21, miR-17, and miR-92 in patients with CC who underwent radical surgery and adjuvant chemotherapy may have diagnostic value for differentiating between recurred and non-recurred patients.

23 March 2019 in Clinical & Investigative Medicine
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Journal Article
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NCNikolay Conev
Nikolay Conev
YKYavor K. Kashlov
Yavor K. Kashlov
EDEleonora G. Dimitrova
Eleonora G. Dimitrova
MBMargarita K. Bogdanova
Margarita K. Bogdanova
BCBorislav G. Chaushev
Borislav G. Chaushev
IDIvan S. Donev
Ivan S. Donev
Background: Colorectal cancer is one of the primary causes of cancer-related deaths and 5-fluorouracil (5-FU) therapy remains the cornerstone of treatment in these patients. Resistance to 5-FU represents a major obstacle; therefore, finding new predictive and prognostic markers is crucial for improvement of patient outcomes. Recently a new type of programmed cell death was discovered—necroptosis, which depends on receptor interacting protein 3 (RIPK3). Preclinical data showed that necroptotic cell death is an important effector mechanism of 5-FU-mediated anticancer activity. Purpose: To investigate the predictive and prognostic performance of RIPK3 expression in primary tumors. Methods: Colon cancer patients (n=74) with metastatic stage were included in this retrospective study and all were treated with first-line 5-FU based chemotherapy. Immunohistochemical staining was performed. Results: The progression free survival for the low expression group of RIPK3 was 5.6 months (95% CI, 4.4-6.8) vs 8.4 months (95% CI, 6.4-10.3) of the group with high expression (p=0.02). Moreover, patients with high expression of RIPK3 were associated with lower risk of disease progression HR 0.61 (95% CI, 0.38-0.97; p=0.044). Patients with high expression levels of RIPK3 also had significantly longer mean overall survival (OS) of 29.3 months (95% CI, 20.8-37.8) as compared with those with low expression: 18.5 months (95% CI, 15.06-21.9) (p= 0.036). In addition, univariate analysis showed that high level of RIPK3 expression was associated with a longer OS HR 0.59 (95% CI, 0.35-0.98; p=0.044). Conclusions: This study suggests that expression of RIPK3 in primary tumors of metastatic colon cancer patients should be further investigated for its potential as a promising predictive and prognostic marker.

15 March 2021 in Current Oncology
Verified
Journal Article
Open access
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Maria RadanovaMaria Radanova
Maria Radanova
GMGalya Mihaylova
Galya Mihaylova
ZMZhasmina Mihaylova
Zhasmina Mihaylova
DIDesislava Ivanova
Desislava Ivanova
Oskan Bahidinov TasinovOskan Bahidinov Tasinov
Oskan Bahidinov Tasinov
IDIvan Donev
Ivan Donev
The present study evaluated the prognostic role of circulating miRNA-618 in patients with metastatic colon cancer (mCC) and whether miR-618 gene rs2682818 single nucleotide polymorphisms (SNP) are associated with colon cancer susceptibility and expression levels of mature miR-618. In total, 104 patients with mCC before starting the chemotherapy were investigated. The expression status of circulating miR-618 in mCC was evaluated by quantitative PCR. TaqMan PCR assay was used for rs2682818 SNP genotyping. miR-618 was overexpressed in serum of mCC patients. Patients with high and intermediate expression of miR-618 had a significantly longer mean overall survival (OS) of 21 months than patients with low expression—16 months. In addition, multivariate Cox regression analysis confirmed the association between high/intermediate levels of miRNA-618 and longer OS, HR = 0.51, 95% CI: 0.30–0.86, p = 0.012. miR-618 rs2682818 SNP significantly decreased the risk of colon cancer susceptibility in both heterozygous codominant (AC vs. CC, OR = 0.39, 95% CI: 0.17–0.88, p = 0.024) and overdominant (AC vs. CC + AA, OR = 0.37, 95% CI: 0.16–0.85, p = 0.018) genetic models. Our data suggest that circulating miRNA-618 could be useful as a prognostic biomarker in mCC. Patients harboring AC rs2682818 genotype have a decreased risk for colon cancer in comparison with patients with CC and AA genotypes.