Ondrej Blaha, PhD
Cards
About
Titles
Associate Research Scientist in Biostatistics
Biography
Dr. Blaha's research interests span around clinical trials, specifically cluster randomized, pragmatic trials with time-to-event outcomes. Currently, he has two main research topics: (1) Additive model for cluster randomized trials and (2) Exact Platform design for multi-arm, multi-stage trials.
Ondrej is currently an Associate Research Scientist at Yale Center for Analytical Sciences (YCAS). He holds a Ph.D. in Biostatistics from LSU and M.Sc. in Biostatistics from Hasselt University, Belgium. Before joining Yale University, he worked as a senior Biostatistician at Stanford University, School of Medicine.
Appointments
Biostatistics
Associate Research ScientistPrimary
Other Departments & Organizations
Education & Training
- Postdoctoral Associate
- Yale University
- PhD
- LSU HSC, Biostatistics
- MSc
- Hasselt University, Biostatistics
- BC
- Charles University, General Mathematics
Research
Publications
2024
Perioperative Modified FOLFIRINOX for Resectable Pancreatic Cancer
Cecchini M, Salem R, Robert M, Czerniak S, Blaha O, Zelterman D, Rajaei M, Townsend J, Cai G, Chowdhury S, Yugawa D, Tseng R, Arbelaez C, Jiao J, Shroyer K, Thumar J, Kortmansky J, Zaheer W, Fischbach N, Persico J, Stein S, Khan S, Cha C, Billingsley K, Kunstman J, Johung K, Wiess C, Muzumdar M, Spickard E, Aushev V, Laliotis G, Jurdi A, Liu M, Escobar-Hoyos L, Lacy J. Perioperative Modified FOLFIRINOX for Resectable Pancreatic Cancer. JAMA Oncology 2024, 10 PMID: 38900452, PMCID: PMC11190830, DOI: 10.1001/jamaoncol.2024.1575.Peer-Reviewed Original ResearchProgression-free survivalPancreatic ductal adenocarcinomaOverall survivalCtDNA levelsPhase 2 nonrandomized controlled trialAnalysis of circulating tumor DNAMedian progression-free survivalResectable pancreatic ductal adenocarcinomaControlled trialsAssess surgical candidacyBaseline ctDNA levelModified 5-fluorouracilResectable pancreatic cancerPancreatic protocol computed tomographyAssociated with recurrenceTumor molecular featuresAggressive malignant tumorKaplan-Meier estimatesRandomized clinical trialsStandard of careCtDNA-positivePreoperative cyclesNonrandomized controlled trialsUnresectable diseaseModified FOLFIRINOXA Bayesian platform trial design with hybrid control based on multisource exchangeability modelling
Wei W, Blaha O, Esserman D, Zelterman D, Kane M, Liu R, Lin J. A Bayesian platform trial design with hybrid control based on multisource exchangeability modelling. Statistics In Medicine 2024, 43: 2439-2451. PMID: 38594809, DOI: 10.1002/sim.10077.Peer-Reviewed Original Research
2023
Validation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Were Treated with Hypomethylating Agents (HMA)
Kewan T, Bewersdorf J, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, Amaya M, Zeidner J, Savona M, Stempel J, Chandhok N, Logothetis C, Ramaswamy R, Rose A, Roboz G, Rolles B, Wang E, Harris A, Shallis R, Xie Z, Padron E, Maciejewski J, Sallman D, Della Porta M, Komrokji R, Zeidan A. Validation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Were Treated with Hypomethylating Agents (HMA). Blood 2023, 142: 3240. DOI: 10.1182/blood-2023-186340.Peer-Reviewed Original ResearchComplete remission rateOverall response rateOutcome of ptsMedian overall survivalOverall survivalHypomethylating agentHMA initiationHR-MDSC-indexRisk groupsScoring systemInternational Prognostic Scoring SystemResponse criteriaPrognostic scoring systemHigh-risk diseaseLarge multicenter cohortHigh-risk groupHarrell's C-indexLog-rank testPrediction of outcomeDifferent scoring systemsSubsequent validation studiesHMA cyclesMedian followAllogeneic HSCTImpact of Type of Hypomethylating Agent (HMA) Used on Outcomes of Patients (Pts) with Higher-Risk Myelodysplastic Syndromes/Neoplasms (HR-MDS) - a Large, Multicenter, Retrospective Analysis
Bewersdorf J, Kewan T, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Uy G, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, McMahon C, Zeidner J, Savona M, Stempel J, Chandhok N, Ramaswamy R, Roboz G, Rolles B, Wang E, Harris A, Amaya M, Hawkins H, Grenet J, Gurnari C, Shallis R, Xie Z, Maciejewski J, Sallman D, Della Porta M, Komrokji R, Zeidan A. Impact of Type of Hypomethylating Agent (HMA) Used on Outcomes of Patients (Pts) with Higher-Risk Myelodysplastic Syndromes/Neoplasms (HR-MDS) - a Large, Multicenter, Retrospective Analysis. Blood 2023, 142: 4613. DOI: 10.1182/blood-2023-178728.Peer-Reviewed Original ResearchCox multivariable regression modelOverall survivalHMA initiationHypomethylating agentMultivariable regression modelsTP53 mutationsAllo-HCTComplete remissionComplex karyotypePartner drugsBone marrowSurvival analysisAllogeneic hematopoietic cell transplantMultivariable Cox regression modelsTreatment typeOverall responseAdverse genetic featuresMedian overall survivalOutcomes of patientsHematopoietic cell transplantAdverse overall survivalKaplan-Meier methodCox regression modelLog-rank testPredictors of responseValidation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Underwent Allogenic Stem Cell Transplantation (HSCT)
Kewan T, Bewersdorf J, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Uy G, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, Amaya M, Zeidner J, Savona M, Stempel J, Chandhok N, Logothetis C, Cochran H, Rose A, Roboz G, Wang E, Rolles B, Harris A, Shallis R, Xie Z, Padron E, Maciejewski J, Sallman D, Della Porta M, Komrokji R, Zeidan A. Validation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Who Underwent Allogenic Stem Cell Transplantation (HSCT). Blood 2023, 142: 4980. DOI: 10.1182/blood-2023-186578.Peer-Reviewed Original ResearchOverall survivalHigh-risk groupUnderwent HSCTC-indexRisk groupsHigh riskDonor typeInternational Prognostic Scoring SystemAllogenic stem cell transplantationTime of HSCTMedian overall survivalReduced-intensity conditioningSignificant OS differencePrognostic scoring systemRisk stratification toolTime of diagnosisStem cell transplantationSingle-institution analysisLog-rank testHarrell's C-indexDifferent overall survivalCox proportional hazardsHMA cyclesHaploidentical donorsMaintenance therapyEvaluation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) with Missing Molecular Data
Kewan T, Bewersdorf J, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, Amaya M, Zeidner J, Savona M, Stempel J, Chandhok N, Logothetis C, Cochran H, Singh A, Roboz G, Rolles B, Wang E, Harris A, Shallis R, Xie Z, Padron E, Sallman D, Maciejewski J, Della Porta M, Komrokji R, Zeidan A. Evaluation of the Molecular International Prognostic Scoring System (IPSS-M) in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) with Missing Molecular Data. Blood 2023, 142: 4607. DOI: 10.1182/blood-2023-187053.Peer-Reviewed Original ResearchValidation of the Composite Complete Response (cCR) Definitions in the International Working Group (IWG) 2023 Criteria in Patients (Pts) with Higher-Risk Myelodysplastic Syndromes/Neoplasms (HR-MDS) Treated with Hypomethylating Agents (HMA) - a Large, Multicenter, Retrospective Analysis from the Validate Database
Bewersdorf J, Kewan T, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Uy G, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, McMahon C, Zeidner J, Savona M, Stempel J, Chandhok N, Logothetis C, Roboz G, Rolles B, Wang E, Harris A, Amaya M, Hawkins H, Grenet J, Shallis R, Xie Z, Maciejewski J, Sallman D, Della Porta M, Komrokji R, Zeidan A. Validation of the Composite Complete Response (cCR) Definitions in the International Working Group (IWG) 2023 Criteria in Patients (Pts) with Higher-Risk Myelodysplastic Syndromes/Neoplasms (HR-MDS) Treated with Hypomethylating Agents (HMA) - a Large, Multicenter, Retrospective Analysis from the Validate Database. Blood 2023, 142: 324. DOI: 10.1182/blood-2023-180299.Peer-Reviewed Original ResearchImproved OSHypomethylating agentHMA initiationMedian OSResponse assessmentTP53 mutationsResponse definitionsPartial hematologic recoveryPredictors of OSMultivariable Cox modelBone marrow blastsKaplan-Meier analysisLog-rank testOverall response rateEfficacy of therapyMultivariable regression modelsReal-world analysisAllo-HCTBM assessmentBM evaluationHemoglobin thresholdHematologic recoveryMarrow blastsMedian durationMedian ageClinical Implications of TP53 Mutations/Allelic State in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Treated with Hypomethylating Agents (HMA)- a Multicenter, Retrospective Analysis from the Validate Database
Kewan T, Bewersdorf J, Blaha O, Stahl M, Al Ali N, DeZern A, Sekeres M, Carraway H, Desai P, Griffiths E, Stein E, Brunner A, Amaya M, Zeidner J, Savona M, Stempel J, Chandhok N, Cochran H, Ramaswamy R, Singh A, Roboz G, Rolles B, Wang E, Harris A, Shallis R, Xie Z, Padron E, Maciejewski J, Della Porta M, Komrokji R, Sallman D, Zeidan A. Clinical Implications of TP53 Mutations/Allelic State in Patients (Pts) with Myelodysplastic Syndromes/Neoplasms (MDS) Treated with Hypomethylating Agents (HMA)- a Multicenter, Retrospective Analysis from the Validate Database. Blood 2023, 142: 1002. DOI: 10.1182/blood-2023-186875.Peer-Reviewed Original ResearchOverall response rateMedian overall survivalOverall survivalComplete responseHMA initiationHMA therapyMultivariable Cox proportional hazards regression modelsCox proportional hazards regression modelHigh-risk disease featuresComplex karyotypeProportional hazards regression modelsWorse overall survivalLog-rank testHazards regression modelsSignificant differencesLogistic regression modelsAllogenic HSCTBM biopsyHMA cyclesMDS-EBTherapy initiationMedian ageRegression modelsCR ratePoor outcomeImmunoPET Imaging Identifies the Optimal Timepoint for Combination Therapy in Xenograft Models of Triple-Negative Breast Cancer
Li Z, Belitzky E, Blaha O, Cavaliere A, Katz S, Aboian M, Melegari L, Rajabimoghadam K, Kurpiewski S, Zhu X, Marquez-Nostra B. ImmunoPET Imaging Identifies the Optimal Timepoint for Combination Therapy in Xenograft Models of Triple-Negative Breast Cancer. Cancers 2023, 15: 1589. PMID: 36900378, PMCID: PMC10001369, DOI: 10.3390/cancers15051589.Peer-Reviewed Original ResearchTriple-negative breast cancerPositron emission tomographyDays post-treatment initiationCDX-011Longitudinal positron emission tomographyPost-treatment initiationTyrosine kinase inhibitorsWestern blot analysisTreatment initiationXenograft modelGPNMB expressionXenografted miceCombination therapyBreast cancerMDA-MB-468 xenograft modelBlot analysisKinase inhibitorsMDA-MB-231 xenograft modelCombination-treated groupControl-treated groupLower overall survivalVehicle control groupCombination of dasatinibSubgroup of miceTumor cell lysatesTaking a chance: How likely am I to receive my preferred treatment in a clinical trial?
Walter S, Blaha O, Esserman D. Taking a chance: How likely am I to receive my preferred treatment in a clinical trial? Statistical Methods In Medical Research 2023, 32: 572-592. PMID: 36628522, PMCID: PMC9983058, DOI: 10.1177/09622802221146305.Peer-Reviewed Original ResearchConceptsPatient preference designConcordance ratePreferred treatmentClinical trialsDifferent treatment preferencesProportion of patientsParallel group designPreference designPatient's primary motivationTrial patientsPoor outcomeBlinded trialClinical equipoiseTreatment preferencesTwo-armZelen designAlternative treatmentStudy outcomesStudy designTrialsTreatmentPatientsPotential participantsOutcomesGroup design