The following discussion illustrates a project that is well suited to the capabilities of an independent consultant in the Umbrex Biotechnology Practice. This is an illustrative example. Umbrex consultants adapt their methodology, timeline, and deliverables to the specific needs of each client.
1) Client Situation
The client operated within the therapeutics-focused biotech ecosystem and required support with Health Economic Modeling And Evidence Synthesis in the context of Biotechnology. Teams across Emerging Therapeutic Biotech (Preclinical), Clinical-Stage Biotech (Phase I–III), Commercial Biotech (Post-Approval), Platform Biotech (Therapeutic Discovery), and Biotech Investors & Incubators requested a robust approach to build cost-effectiveness and budget impact models—partitioned survival and Markov—and to conduct indirect treatment comparisons and network meta-analyses (ITC/NMA) aligned to HTA and payer requirements. The diagnostic surfaced concrete gaps that undermined readiness for submissions and payer dialogues:
- Comparator and network uncertainty. Clinical teams had not aligned appropriate comparators by market; trials differed in populations, endpoints, and follow-up. The network geometry was sparse; anchored NMA feasibility was unclear; unanchored MAIC/STS approaches lacked pre-specified plans for covariate selection and balance diagnostics.
- Survival and durability extrapolations not HTA-grade. Parametric extrapolations were selected without formal plausibility tests or external validation. Mixture-cure, spline-based, and piecewise models had not been explored; proportional hazards assumptions were applied by default despite evidence of non-proportional hazards.
- Utilities and HRQoL evidence incomplete. EQ-5D (3L/5L) collection, mapping, and valuation sets were inconsistently documented; utility decrements for adverse events and post-progression health states were missing; country tariffs and elicitation methods were not aligned to agency preferences.
- Cost and HRU inputs insufficiently localized. Unit costs, treatment pathways, administration settings, wastage, and adverse event management costs were not tailored to country tariffs or benefit routing (medical vs. pharmacy) conventions; discounting and perspective assumptions were inconsistent across draft models.
- Model structure and transparency gaps. The base model did not have a technical support document or assumption book; structural assumptions (treatment stopping rules, waning, dose escalation, subsequent therapy mix) were not explicit; parameter uncertainty and structural uncertainty were not separated, limiting interpretability of PSA and DSA.
- Evidence synthesis not documented per best practice. Systematic literature review methods lacked PRISMA documentation and risk-of-bias assessment. Heterogeneity, transitivity, and network consistency were not tested rigorously; node-splitting and design-by-treatment interaction diagnostics were absent.
- Country adaptation delays. Affiliates lacked country kits for inputs, utilities, tariffs, and practice patterns; validation and face-validity review processes were not defined; translation and redaction workflows were unscheduled.
- Economic results not “decision-grade.” ICERs and budget impact outputs were sensitive to a small set of assumptions; willingness-to-pay thresholds and severity modifiers were not addressed; scenario analyses for alternative comparators and price corridors were missing.
- US payer materials not aligned. AMCP dossier draft did not include credible BIM scenarios calibrated to payer mixes; assumptions on adherence, persistence, and discontinuation were not benchmarked to real-world data; indirect comparison limitations were not disclosed transparently.
- Operational readiness for HTA technical engagement limited. No plan existed for technical queries, sensitivity reruns, or providing model files to agencies; model code was not version-controlled; QA checks and replication logs were incomplete.
2) Project Objective
The primary objective focused on building HTA- and payer-grade health economic models—cost-effectiveness and budget impact—using partitioned survival or Markov cohort structures as appropriate, and conducting rigorous indirect treatment comparisons and network meta-analyses to supply decision-grade evidence for HTA submissions and payer engagements.
Secondary objectives included:
- Executing a PRISMA-compliant systematic literature review with risk-of-bias assessment and data extraction ready for NMA/ITC.
- Designing and implementing ITC/NMA (anchored where feasible; MAIC/STS for unanchored comparisons) with heterogeneity, transitivity, and consistency diagnostics.
- Performing survival analysis and extrapolation (parametric, flexible spline, mixture-cure, piecewise) with external validation and plausibility checks.
- Building a transparent global cost-effectiveness model (PSM/Markov) and a budget impact model (BIM), with assumption books, validation logs, and Good Modeling Practice documentation (ISPOR–SMDM).
- Creating country adaptation packs (utilities, tariffs, resource use, discounting, perspective) with affiliate training and QA processes.
- Producing sensitivity analyses (deterministic and probabilistic), scenario analyses, and—where useful—expected value of information (EVPI/EVPPI) to guide evidence priorities.
- Preparing technical support documents and response engines for HTA queries; enabling file transfers and reproducibility with version control and audit trails.
- Supplying GVD/AMCP-ready content and payer-calibrated BIM outputs for US and global engagements.
3) Methodology and Approach
Workstream 1: Scoping, Problem Definition, and HTA Requirements Mapping
We aligned objectives, comparators, outcomes, and methodological standards across priority markets.
- Activities we conducted:
- Defined decision context: indication, line of therapy, subgroups, endpoints (OS, PFS, ORR, PROs), and comparators by country; mapped HTA technical requirements (NICE, G-BA/IQWiG, HAS, SMC) and payer expectations.
- Agreed model perspectives (payer/NHS), time horizons (lifetime or disease-specific), discount rates, severity modifiers, WTP thresholds, and handling of treatment waning and stopping rules.
- Authored a modeling analysis plan and evidence synthesis plan with pre-specified methods and diagnostics, and a governance cadence for decisions and trade-offs.
- Tools/frameworks used: HTA requirement matrix, modeling analysis plan, ITC/NMA protocol, assumption register, risk register.
- Stakeholders involved: HEOR lead, biostatistics, clinical, country access leads, pricing/contracting.
Workstream 2: Systematic Literature Review (SLR) and Data Extraction
We built a PRISMA-compliant evidence base to feed the models and comparisons.
- Activities we conducted:
- Developed search strategies, screened records (dual independent review), extracted study-level data (efficacy, safety, HRQoL, HRU), and assessed risk of bias (Cochrane, ROBINS-I) and evidence quality (GRADE).
- Constructed standardized evidence tables; digitized Kaplan–Meier curves; verified data integrity; compiled covariates relevant to effect modification for MAIC/STS if needed.
- Tools/frameworks used: PRISMA flow, extraction templates, risk-of-bias tools, KM digitization QA, data dictionaries.
- Stakeholders involved: HEOR analysts, statisticians, medical affairs reviewers.
Workstream 3: Indirect Treatment Comparisons and Network Meta-Analysis
We quantified comparative effectiveness credibly and transparently.
- Activities we conducted:
- Built network geometry; performed Bayesian or frequentist NMA under fixed or random effects depending on heterogeneity; assessed transitivity and consistency via node-splitting and design-by-treatment interaction tests.
- When networks could not be anchored, executed unanchored MAIC or simulated treatment comparison (STC) with pre-specified covariates, balance diagnostics (effective sample size), and sensitivity analyses for unmeasured confounding.
- Estimated hazard ratios, odds ratios, or mean differences for key endpoints; generated uncertainty distributions for economic modeling; documented all assumptions and diagnostics per HTA technical support checklists.
- Tools/frameworks used: NMA code (R/BUGS/JAGS/Stan), MAIC/STS scripts, heterogeneity and consistency diagnostics, model convergence checks, forest and league tables.
- Stakeholders involved: biostatistics/modeling, HEOR, clinical reviewers.
Workstream 4: Survival Analysis and Extrapolation
We developed robust survival functions aligned with trial data and external plausibility.
- Activities we conducted:
- Fitted parametric distributions (exponential, Weibull, Gompertz, log-logistic, log-normal, generalized gamma), flexible spline models, piecewise functions, and mixture-cure models where biologically plausible.
- Selected models based on visual fit, AIC/BIC, residuals, and clinical plausibility; validated extrapolations against RWE benchmarks or registry data; assessed proportional hazards and used time-varying hazards when needed.
- Generated treatment-specific survival inputs (OS, PFS, TTD, time-on-treatment) with correlated uncertainty structures for economic modeling.
- Tools/frameworks used: survival modeling scripts, plausibility and external validation checklists, correlation matrices for joint sampling.
- Stakeholders involved: biostatistics, clinical, HEOR modeling team.
Workstream 5: Cost-Effectiveness Model Development (PSM/Markov)
We built a transparent, validated model aligned to ISPOR–SMDM Good Modeling Practice.
- Activities we conducted:
- Chose structure (partitioned survival vs. state-transition Markov with tunnel states) based on disease dynamics and data; defined health states (progression-free, progressed, death) and transitions.
- Populated utilities (EQ-5D-3L/5L with country tariffs), disutilities for adverse events, and HRU; included costs for drugs (dose, wastage), administration, monitoring, AE management, subsequent therapies, and terminal care.
- Implemented deterministic sensitivity analysis (DSA), probabilistic sensitivity analysis (PSA), and scenario analyses for structural uncertainty (time horizon, waning, stopping rules, subsequent therapy mix). Documented model equations, data sources, and version control.
- Tools/frameworks used: model platform (Excel/R/TreeAge), technical support document, assumption book, validation plan, CHEERS 2022 reporting checklist.
- Stakeholders involved: HEOR economists, statisticians, clinical, affiliate reviewers.
Workstream 6: Budget Impact Model (BIM)
We quantified plan-level budgetary effects and operational implications.
- Activities we conducted:
- Defined target population by epidemiology, eligibility, and uptake curves; modeled resource utilization changes (drug, administration, HRU); included adherence and persistence impacts; captured channel differences (medical vs. pharmacy benefit) and site-of-care shifts.
- Produced plan-specific outputs (PMPM, total plan cost, per-treated member) with scenario toggles for distribution models (SP vs. buy-and-bill), coding/reimbursement assumptions, and dose escalation.
- Tools/frameworks used: payer-calibrated BIM engine, input libraries by segment, sensitivity dashboards for plan archetypes.
- Stakeholders involved: market access, HEOR, pricing, US payer strategy.
Workstream 7: Calibration, Validation, and Quality Assurance
We ensured models and comparisons were reproducible, credible, and inspection-ready.
- Activities we conducted:
- Executed face validation (clinical plausibility checks), cross-validation with alternative data sources, internal and external validation (replication of published results where feasible), and extreme value testing.
- Maintained validation logs, replication scripts, and QA checklists; separated structural from parameter uncertainty; documented all changes in an auditable change log.
- Tools/frameworks used: validation plan and log, replication notebooks, version control repository, peer review templates.
- Stakeholders involved: modeling leads, independent reviewers, affiliates as observers.
Workstream 8: Country Adaptation and Affiliate Enablement
We localized inputs and narratives and trained affiliates.
- Activities we conducted:
- Created country input packs (tariffs, practice patterns, utility sources, discounting, perspectives); developed adaptation SOPs and QA steps; supported local survival validation and comparator alignment.
- Delivered training on model operation, scenario runs, and interpretation; provided localization guides and checklists for submission alignment (NICE/SMC/HAS/G-BA).
- Tools/frameworks used: country kit templates, localization checklist, training modules, affiliate feedback tracker.
- Stakeholders involved: affiliates, global HEOR/access, pricing.
Workstream 9: Results Packaging, Narratives, and Technical Engagement
We translated outputs into HTA- and payer-ready content and prepared for queries.
- Activities we conducted:
- Produced base case and sensitivity results with tornado diagrams, CEACs, ICER distributions, and price–ICER curves; crafted narrative for clinical effectiveness and cost-effectiveness by country.
- Prepared a response engine: rapid reruns for alternative comparators, utilities, and costs; standardized figure styles; ensured reproducibility and version control for agency model sharing.
- Tools/frameworks used: results compendium, technical support document, response playbook, figure/footnote style guide.
- Stakeholders involved: HEOR, affiliates, pricing, regulatory.
Workstream 10: Governance, Transparency, and Documentation
We embedded best-practice transparency and decision logs to sustain credibility.
- Activities we conducted:
- Maintained an assumption register, decisions and trade-offs log, and risk register; aligned with CHEERS 2022 reporting; prepared audit-ready documentation for HTA technical scrutiny.
- Instituted a cadence for model and NMA refreshes as new data emerged (interims, RWE), with impact assessments and change control.
- Tools/frameworks used: assumption and decision logs, change control SOP, CHEERS checklist, governance charter.
- Stakeholders involved: HEOR/access leadership, modeling team, affiliates.
4) Data Request
We requested datasets and artifacts necessary to build decision-grade models and evidence syntheses. Typical horizons were current clinical and economic evidence, with 12–24 months forward for planned updates.
- Clinical efficacy and safety:
- CSR tables/figures/listings; IPD or KM curves for OS, PFS, TTD/time-on-treatment; response and duration; AE/SAE incidence and grade; dose modifications, discontinuations.
- Subgroup definitions and results; stratification factors; protocol amendments affecting comparability; PRO/HRQoL data (EQ-5D 3L/5L, EORTC, disease-specific instruments).
- Comparators and external evidence:
- Published comparator trials with KM curves/IPD availability; network information (inclusion/exclusion criteria, endpoint definitions, follow-up durations); real-world datasets (claims/EHR/registries) for HRU, adherence/persistence, mortality, and practice patterns.
- Utilities and HRQoL:
- EQ-5D values by health state and adverse events; mapping algorithms where direct utilities absent (e.g., EORTC to EQ-5D); country tariff sets; utility elicitation methods; QoL decrements for AEs and post-progression.
- Costs and resource use:
- Drug list prices and net price scenarios; dosing schedules, wastage assumptions; administration/infusion costs; monitoring and imaging frequencies; AE management costs; subsequent therapy costs; terminal care; country tariffs and DRG/HRG/CCAM/EBM references.
- Epidemiology and population:
- Incidence/prevalence; eligible population estimates by line of therapy; demographic distributions; uptake curves by market.
- Model parameters and conventions:
- Discount rates by country; perspective (payer/NHS); time horizon; stopping rules; waning assumptions; subsequent therapy mix and sequencing; severity modifiers and WTP thresholds where applicable.
- Evidence synthesis artifacts:
- SLR search strings and screen logs; extracted datasets; risk-of-bias assessments; NMA/MAIC protocols; convergence diagnostics and code; consistency and heterogeneity tests.
- Operational and governance:
- Model platform preferences (Excel/R/TreeAge); version control repositories; QA checklists; prior HTA feedback and technical queries; affiliate input templates; translation/redaction requirements.
Common data pitfalls included incomplete KM curve digitization or IPD access, inconsistent comparator definitions across sources, missing utilities or non-validated mapping, HRU estimates lacking country relevance, untracked assumptions, and absence of validation logs. We instituted a data dictionary, assumption book, and code repository with version control before model construction.
5) Questions for Client
- Which comparators must be addressed by country, and what tolerance exists for unanchored methods (MAIC/STS) where networks do not connect?
- What perspective, time horizon, and discount rates should govern the base case in each market; what WTP thresholds or severity modifiers should be assumed?
- How should treatment waning, stopping rules, and subsequent therapy mix be modeled; what evidence supports these choices?
- Which utility sources (direct EQ-5D vs. mapping) are acceptable to agencies; how should AE-related disutilities be handled?
- What country priority and sequencing should apply for model adaptations; how will affiliates contribute tariffs, resource use, and practice patterns?
- What price corridors and rebate structures should be tested; how should ERP and contracting constraints shape scenario analyses?
- What risk appetite exists for RWE calibration and external validation; which datasets are accessible for HRU, persistence, and survival plausibility checks?
- What requirements exist for sharing model files and responding to HTA technical queries; what turn-around times and resourcing are acceptable?
- How should US BIM scenarios be parameterized by payer segment; what adherence and discontinuation assumptions are credible?
- Which KPIs will leadership monitor (ICER vs. corridor, price–ICER curves, PSA acceptability, PMPM, scenario sensitivity), and what thresholds trigger strategy adjustments?
6) Interview Guide for Subject Matter Experts
HEOR / Value Evidence Lead
- Which endpoints and outcomes most influence country HTA decisions in this indication; where are current evidence gaps?
- What prior agency feedback informs comparator and utility choices; how have similar submissions been positioned?
- Which assumptions are non-negotiable vs. flexible in the value narrative?
- What publications and congress plans must align with model messages?
- What internal processes govern updates when new data arrive?
Biostatistics / Modeling Lead
- What survival models are plausible given non-proportional hazards; how will we test and select among parametric, spline, mixture-cure, and piecewise forms?
- How will we structure NMA (Bayesian vs. frequentist; fixed vs. random effects); what diagnostics ensure transitivity and consistency?
- What correlation structures will govern joint sampling of OS and PFS in PSA; how will structural uncertainty be separated from parameter uncertainty?
- What validation and replication tests will be executed, and how will code be version-controlled and audited?
- Which subgroups require independent modeling?
Clinical Development / Medical Affairs
- What biologic plausibility supports treatment waning or long-term durability; what trial design features constrain extrapolation?
- Which subsequent therapy sequences reflect practice in key markets; how should cross-over be handled?
- How should PROs and QoL be translated into utilities credibly?
- What clinician narratives will support hearings?
RWE / Data Partnerships Lead
- Which registries or claims datasets can support calibration and external validation; what timelines and governance are realistic?
- How will HRU, adherence, and persistence be estimated and aligned to model structures?
- What risks exist for comparability to trial cohorts, and how will they be managed?
Pricing / Market Access Strategy
- What net price corridors are targeted by market; how should price–ICER curves and budget impact inform launch sequencing and MEA options?
- What ERP and contracting constraints must be reflected in scenarios?
- Which payer segments in the US require distinct BIM assumptions?
Affiliate Access Leads (UK, DE, FR, Scotland)
- What are the country-specific comparator expectations and tariff sources; where are data gaps?
- Which utilities and HRU sources are preferred by local HTAs; what discounting and time horizon conventions must be followed?
- What internal review timelines and translation needs affect submissions?
Quality Assurance / Compliance
- What documentation standards apply (CHEERS, PRISMA, ISPOR–SMDM); how will audit trails and change logs be maintained?
- What policies govern external sharing of models and data; what de-identification or redaction is required?
7) Timeline
We executed a 12–14 week plan tailored to Health Economic Modeling & Evidence Synthesis within Market Access & HEOR.
- Weeks 1–2: Scoping and Requirements
- Aligned decision context, comparators, outcomes, HTA requirements, and modeling conventions; finalized analysis plans (SLR, ITC/NMA, survival, CEA/BIM); established governance and version control.
- Decision Gate A: Approved scope, comparator set, and methods; confirmed data access and country priorities.
- Weeks 3–4: SLR and Data Assembly
- Executed PRISMA-compliant SLR; extracted efficacy/safety/HRQoL/HRU data; digitized KM curves; assessed risk of bias and evidence quality; compiled covariates for MAIC/STS.
- Decision Gate B: Validated evidence base; authorized ITC/NMA and survival analysis.
- Weeks 5–6: ITC/NMA and Survival Modeling
- Built network and ran NMA (anchored) or MAIC/STS (unanchored) with diagnostics; fitted survival models and selected extrapolations with external plausibility checks; generated uncertainty distributions.
- Decision Gate C: Ratified comparative effectiveness and survival inputs; approved model structure (PSM/Markov) and health states.
- Weeks 7–8: CEA and BIM Build
- Constructed global cost-effectiveness and budget impact models; populated utilities, costs, HRU; implemented DSA/PSA/scenarios; produced initial ICERs, CEACs, PMPM, and plan-level outputs.
- Decision Gate D: Cleared model architecture and base case; authorized country adaptation kit development and QA plan.
- Weeks 9–10: Validation, Localization, and Results Packaging
- Completed face/external validation and replication checks; created country input packs and localization SOPs; generated result compendia and price–ICER curves; drafted technical support documents.
- Decision Gate E: Approved validation logs and country kits; scheduled affiliate training and HTA technical engagement preparation.
- Weeks 11–12: Training, Response Engine, and Handoff
- Delivered affiliate training; launched response engine for HTA queries; finalized AMCP/GVD model content; transferred code, assumption books, and documentation with version control.
- Decision Gate F: Authorized submissions and payer engagements; agreed quarterly refresh cadence and impact assessment process for new data.
- Weeks 13–14 (optional): Stress Testing and VOI
- Ran stress tests on alternative comparators, utility sources, and price corridors; executed EVPI/EVPPI where informative; refined risk register and mitigation actions.
Critical path items included comparator and network feasibility, survival extrapolation selection and validation, utility and HRU availability, country tariff sourcing, model transparency and QA, and affiliate readiness for localization and technical engagement.
8) Deliverables
- Systematic Literature Review and Evidence Tables
- PRISMA report, extraction files, risk-of-bias and GRADE assessments, evidence tables for efficacy, safety, HRQoL, HRU, and comparators.
- ITC/NMA Report and Code Package
- Methods and diagnostics, league tables and forest plots, convergence and consistency checks, MAIC/STS balance diagnostics, annotated code, and data used.
- Survival Analysis and Extrapolation Dossier
- Model fits, selection rationale, external plausibility checks, non-proportional hazards assessment, and parameter draws for economic modeling.
- Global Cost-Effectiveness Model (PSM/Markov)
- Base model with technical support document, assumption book, validation log, DSA/PSA results, CEACs, and price–ICER curves.
- Budget Impact Model and Payer Scenarios
- Plan-level outputs (PMPM, total budget impact), adherence/persistence scenarios, channel and site-of-care toggles, and sensitivity dashboards.
- Country Adaptation Kits
- Tariffs, utilities, HRU, discounting, perspective, practice patterns, survival validation notes, and localization checklists.
- Results Compendium and Narrative Pack
- Base case and sensitivity narratives, tornado plots, CEACs, HTA-calibrated messages, and figure libraries for submissions and payers.
- AMCP/GVD Economic Content
- US payer BIM scenarios and global economic summaries with transparent assumptions, aligned to value dossiers.
- HTA Technical Engagement Toolkit
- Response engine SOPs, model sharing protocols, version-controlled code, rerun scripts, and Q&A libraries.
- Governance and Documentation Suite
- Assumption and decision logs, change control records, CHEERS compliance checklist, validation and replication reports, and risk register.
9) Industry Insights
- Comparator alignment dictates credibility
- Appropriate local comparators and transparent ITC/NMA design drive HTA acceptance; anchored comparisons are preferred; unanchored MAIC/STS require rigorous covariate selection, balance diagnostics, and sensitivity to unmeasured confounding.
- Survival extrapolation is scrutinized
- HTAs expect clinical plausibility and external validation beyond statistical fit; flexible and mixture-cure models often outperform simple parametrics when hazards change over time.
- Utilities and HRU must reflect local preferences
- Validated EQ-5D with appropriate country tariffs and robust mapping where needed are essential; IQWiG, NICE, HAS, and SMC each have preferences on utility sources and valuation approaches.
- Transparency beats perfection
- Well-documented assumptions, diagnostics, and validation logs (CHEERS, ISPOR–SMDM) are favored over opaque models; reproducible code and change logs accelerate technical review and reduce rework.
- Structural uncertainty matters
- Stopping rules, waning, subsequent therapy mix, and dose escalation drive ICERs; separating structural from parameter uncertainty clarifies decision risk and negotiation levers.
- NICE severity modifiers and evolving thresholds
- Severity modifiers and equality considerations affect acceptability; scenario analyses and transparent reporting of QALY gains by severity strengthen positions.
- German AMNOG emphasizes clinical added benefit
- G-BA/IQWiG focus on patient-relevant endpoints and subgroup logic; ZVT alignment and hearing readiness are decisive; economic arguments follow added-benefit categorization and price negotiation norms.
- RWE integration is rising—but must be disciplined
- RWE supports calibration and plausibility checks; target trial emulation and careful adjustment are increasingly expected for post-launch reassessments and MEAs.
- Value of information can guide evidence priorities
- EVPI/EVPPI highlights high-impact uncertainties and can justify targeted post-approval studies or data collection agreements.
- What “good” looks like
- A comparator-aligned, transparent ITC/NMA; survival models with external validation; a well-documented PSM/Markov CEA and payer-calibrated BIM; country adaptation kits; sensitivity and scenario analyses that reflect structural uncertainty; technical support and response engines; and governance that maintains transparency and reproducibility across updates.
- Near-term watch points
- NICE method changes, IQWiG expectations for HRQoL and utilities, HAS guidance on ASMR, SMC FAST-TRACK criteria, EU joint clinical assessment implications, biosimilar price dynamics, and privacy constraints on RWE. Quarterly method refreshes and early technical engagement sustain alignment with evolving standards.
Implications for clients we served included enabling Emerging Therapeutic Biotech to convert pivotal data into decision-grade economics before HTA advice; supporting Clinical-Stage Biotech to align comparators, survival, and utilities for first-cycle submissions; equipping Commercial Biotech to maintain favorable positions through country adaptations and RWE; guiding Platform Biotech to standardize SLR/ITC/NMA and models across partnered programs; and providing Biotech Investors & Incubators with clear sightlines to ICER risk, price corridors, and evidence priorities across portfolios.