Companion Diagnostics: Align the Clocks

Drug and diagnostic submissions must land together. When timelines diverge, you

miss launch windows and undermine treatment plans.

This playbook keeps Dx and Rx synchronized. You will establish joint milestones,

line up analytical validation, align labeling, and govern decisions together so

both dossiers reach regulators in harmony.

Why synchronization matters

Regulatory expectations: Authorities evaluate drug benefit–risk alongside

diagnostic performance. Misalignment raises critical questions.

Launch success: Coordinated approvals enable treatment access and payer

discussions.

Operational efficiency: Shared planning avoids duplicated studies and rework.
Patient impact: Accurate diagnostics ensure the right patients get therapy

on day one.

Step 1: Build a joint development and submission plan

Consolidate drug and diagnostic timelines into one roadmap covering clinical

studies, analytical validation, regulatory interactions, manufacturing, and

labeling.

Identify dependencies—e.g., clinical sample availability for assay validation,

diagnostic readiness for pivotal trials.

Assign cross-functional owners and set governance cadence to review progress.
Use shared project tools so status updates stay synchronized.

Step 2: Ensure analytical validation supports clinical claims

Lock study protocols, sample size, and acceptance criteria early with both

teams.

Confirm sample availability (prospective and retrospective) aligns with

timelines.

Track analytical performance metrics (sensitivity, specificity, reproducibility)

as critical-path deliverables.

Document results in both DHF and drug regulatory modules to maintain consistency.

Step 3: Align clinical utility and labeling

Collaborate on clinical trial designs to generate data supporting both drug and

diagnostic claims.

Run joint labeling workshops so drug prescribing information, testing

requirements, and diagnostic IFU messaging align.

Coordinate regulatory content for benefit–risk submissions, CDx summary of

safety and effectiveness, and risk management plans.

Maintain shared review tools capturing approvals and rationale.

Step 4: Govern decisions together

Establish a cross-functional steering committee including Clinical, Regulatory,

Diagnostics, Quality, Commercial, and Medical Affairs.

Review milestone adherence, risk registers, and change requests at each meeting.
Maintain decision logs with context and downstream actions.
Escalate issues (sample shortfalls, assay redesign, labeling changes)

immediately to prevent schedule slips.

Step 5: Prepare coordinated regulatory strategies

Align on submission pathways (FDA PMA, 510(k), EMA parallel review, NMPA

processes).

Schedule joint meetings with agencies to discuss co-development plans.
Harmonize responses to regulatory questions; ensure both dossiers reference the

same data and conclusions.

Plan for international expansions, factoring local diagnostic regulation nuances.

Metrics that show coordination

Milestone adherence for drug and diagnostic deliverables.
Number of late change requests impacting either dossier.
Regulatory questions tied to misalignment (labeling discrepancies, inconsistent

data).

Time from final data lock to synchronized submission.

45-day roadmap

Days 1-10: Map current Rx/Dx timelines, identify gaps, and collect risk

registers.

Days 11-20: Build the joint milestone plan, validate with functional leads,

and launch governance cadence.

Days 21-30: Review analytical validation readiness, secure samples, and

confirm protocol approvals.

Days 31-45: Align labeling drafts, integrate decision logs, and prep

regulatory briefing materials.

Frequently asked questions

Who owns the plan? Shared ownership between drug regulatory lead and

diagnostic program manager, with executive sponsor oversight.

How do we manage external diagnostic partners? Embed them in governance,

share milestones, and require documentation in controlled systems.

What if the diagnostic lags? Reassess launch sequencing, evaluate bridging

studies, or negotiate phased submissions with regulators.

How do we handle global roll-outs? Build regional appendices to the master

plan, accounting for local diagnostic regulation timelines.

Sustain the win

Hold integrated governance meetings monthly, refresh plans after major study

readouts, and rotate leadership roles. Celebrate submissions where both dossiers

went in together—proof the clocks are synced and patients benefit without delay.