# Long-term Safety and Efficacy Study and Dose-Escalation Substudy of PF 06838435 in Individuals With Hemophilia B

> **NCT03307980** · PHASE2 · ACTIVE_NOT_RECRUITING · sponsor: **Pfizer** · enrollment: 21 (actual)

## Conditions studied

- Hemophilia B

## Interventions

- **BIOLOGICAL:** PF-06838435 (formerly SPK-9001)

## Key facts

- **NCT ID:** NCT03307980
- **Lead sponsor:** Pfizer
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** ACTIVE_NOT_RECRUITING
- **Start date:** 2017-06-22
- **Primary completion:** 2029-05-29
- **Final completion:** 2029-10-25
- **Target enrollment:** 21 (ACTUAL)
- **Last updated:** 2026-05-12


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT03307980

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT03307980, "Long-term Safety and Efficacy Study and Dose-Escalation Substudy of PF 06838435 in Individuals With Hemophilia B". Retrieved via AI Analytics 2026-09-21 from https://api.ai-analytics.org/clinical/NCT03307980. Licensed CC0.

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