Voxelotor in Anemia, Sickle Cell: NCT04581356 Clinical Landscape Report 2026

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This Clinical Landscape Report was built with PatSnap Life Sciences MCP workflows. Clinical Trials MCP supplies protocol and result records, Drug & Asset MCP adds asset context, and Company & Deal Intelligence MCP resolves sponsor background. Use the same structured MCP building blocks in your research workflow.

Data snapshot: 16 October 2026. This strategic research report is not medical, regulatory or investment advice. Trial status and dates can change.

Executive view

NCT04581356 evaluates Voxelotor in Anemia, Sickle Cell. The disclosed sponsor is Pediatric Specialists of Virginia LLC, the design is Interventional, and the geographic footprint is United States. The first listed primary endpoint is Peak oxygen consumption (VO2), assessed over 8 weeks.

The key landscape question is whether this protocol can generate a clinically interpretable signal relative to nearby programs. Phase alone is not a measure of evidence quality. Endpoint relevance, comparator choice, masking, enrollment feasibility, patient selection, country coverage and follow-up must be considered together.

PatSnap MCP Servers make this assessment reproducible by keeping protocol facts, result evidence, asset attributes and sponsor identity in separate structured calls.

How the MCP evidence stack was assembled

Clinical Trials MCP clinical_trial_fetch retrieved the design, outcomes, phase, status, enrollment, sponsor, countries and timing for NCT04581356 and selected peers. clinical_trial_result_fetch supplied detailed result records from the wider Anemia, Sickle Cell landscape. Drug & Asset MCP drug_fetch was queried for Voxelotor, while Company & Deal Intelligence MCP organization_fetch was queried for Pediatric Specialists of Virginia LLC.

This separation reduces a common diligence error: treating a registry label, a company description or a result excerpt as if each represented the complete evidence package. Explore the source workflow at the PatSnap MCP marketplace.

Trial landscape table

The table aligns endpoints, sponsors, phases, geographies and readout proxies. It is descriptive, not a head-to-head efficacy comparison. Differences in population, baseline risk, intervention schedule and follow-up can dominate apparent cross-trial differences.

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Protocol design and endpoint interpretation

NCT04581356 is a Phase 4, completed study with not reported planned participants. Allocation is N/A, masking is None (Open Label), and the intervention model is Single Group Assignment.

The primary endpoint is “Peak oxygen consumption (VO2)” over “8 weeks.” The retrieved endpoint description is: Change in peak oxygen consumption (VO2) measured in CPET after voxelotor treatment.

Interpretation should test whether the endpoint captures a clinically meaningful change, whether its time horizon matches the proposed biology, and whether treatment discontinuation or missing data can bias the estimate. The planned enrollment of not reported should be assessed against expected effect size, event frequency, multiplicity, subgroup plans and attrition.

No named control drug was returned in the protocol field set. A placebo comparator can strengthen internal efficacy assessment, while an active comparator may better test clinical differentiation. Single-arm and open-label programs require greater weight on objective outcomes, independent assessment and external benchmarks.

Indexed readouts in the surrounding landscape

0 recent result records were selected as contextual evidence for Anemia, Sickle Cell. These records do not establish direct evidence for NCT04581356 unless the registration number matches.

Result fields should be reconciled with the source record before quantitative comparison. Population definitions, analysis sets, dose cohorts, estimands, confidence intervals, rescue therapy and follow-up can materially change the meaning of a numerical endpoint. Clinical Trials MCP supports repeatable refreshes as result records change.

Asset and sponsor context

Voxelotor is indexed as Small molecule drug with Sickle haemoglobin biology and a global stage of Withdrawn. The asset profile lists Global Blood Therapeutics, Inc. as an originator or developer.

Pediatric Specialists of Virginia LLC is indexed in an unreported country with the website https://psvcare.org. Pediatric Specialists of Virginia is a medical center, that provides access to the doctors and resources of both organizations. The record lists an unreported number of development-stage drug assets.

For execution diligence, monitor sponsor ownership, collaborator additions, site expansion, protocol amendments and enrollment revisions. A change in ownership or geography can alter operational confidence as well as the commercial meaning of a future readout.

Development white space

1. Endpoint white space. Determine whether a more patient-relevant outcome, longer durability window or blinded central assessment would resolve uncertainty left by the current endpoint.
2. Population white space. Test biomarker-defined, treatment-line or risk-stratified subgroups where effect size and unmet need could be clearer.
3. Comparator white space. Identify whether the study can support differentiation against the current standard of care rather than only activity against baseline or placebo.
4. Geographic white space. Assess whether the disclosed footprint supports recruitment, regulatory transferability and commercial generalizability.
5. Sequencing white space. Clarify whether Voxelotor is intended for monotherapy, combination, maintenance, rescue or an earlier treatment line.

White space should be framed as an unanswered development question, not merely an unoccupied mechanism label. A credible program closes a measurable clinical uncertainty with a design that can be executed and interpreted.

Strategic implications and next readouts

For sponsors, the endpoint hierarchy, safety window, enrollment pace and protocol amendment history should all support the same target product profile. Advancement criteria should be set before the readout and tied to clinical effect, uncertainty, tolerability and operational feasibility.

For business-development teams, differentiation may come from a sharper population, stronger comparator, more durable benefit, simpler delivery or clearer sequencing role. For investors, the central risk is evidence quality relative to time and capital, not the phase label in isolation.

Track recruitment status, enrollment changes, primary-completion timing, endpoint revisions, new result records, sponsor ownership and collaborator changes. Re-run the PatSnap MCP workflow when a surrogate becomes a clinical outcome, a single-country study expands, the comparator changes or a new result materially shifts the competitive benchmark.

Source trail and bottom line

Anchor trial: NCT04581356
Protocol source: https://clinicaltrials.gov/study/NCT04581356
MCP sources: Clinical Trials MCP (clinical_trial_fetch and clinical_trial_result_fetch); Drug & Asset MCP (drug_fetch); Company & Deal Intelligence MCP (organization_fetch).
Data snapshot: 16 October 2026.

Voxelotor in Anemia, Sickle Cell is best understood through the interaction of protocol design, surrounding readouts, asset context and sponsor execution. The current record makes Peak oxygen consumption (VO2) and 2021-10-25 the leading decision points.

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