Adaptive Platform Trial for Pain Management in Sickle Cell Vaso-Occlusive Crisis (PAMAVOC)

September 11, 2026 updated by: Assistance Publique - Hôpitaux de Paris

Adaptive Platform Trial for Pain Management During Vaso-Occlusive Crisis in Adult Patients With Sickle Cell Disease

Sickle cell disease (SCD) is a severe hemoglobinopathy, characterized by recurrent vaso-occlusive crises (VOC) causing intense pain and frequent hospitalizations in adult patients. Current French and British guidelines recommend rapid administration of strong opioids, primarily through patient-controlled analgesia (PCA), as the reference treatment for hospitalized patients experiencing VOC. However, opioid use is associated with dose-dependent adverse effects, including nausea, constipation, pruritus, sedation, and hypoventilation, the latter representing a risk factor for acute chest syndrome.

The hypothesis underlying this study is that multimodal analgesia-combining morphine PCA with co-analgesics such as paracetamol-can significantly reduce morphine consumption during hospitalization compared to opioid-only analgesia, while maintaining effective pain control. Although several co-analgesic agents (paracetamol, NSAIDs, nefopam, tramadol, ketamine) are recommended by expert guidelines, including those from the American Society of Hematology (2020) and French recommendations (2025), the level of evidence supporting their use in adult sickle cell patients remains low or non-existent for most agents, with no randomized controlled trials available for nefopam, tramadol, or ketamine.

Using an adaptive platform design, this trial aims to compare multiple analgesic strategies against standard opioid-based care, generating higher-quality evidence to optimize pain management protocols for adult patients experiencing VOC

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

400

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adult patients (age ≥18 years)
  • Diagnosed with major sickle cell syndrome (SS homozygous, SC or Sβ° or Sβ+ thalassemia compound heterozygous)
  • Hospitalized and presenting with a vaso-occlusive crisis (VOC), defined as acute pain or tenderness affecting at least one part of the body, including the limbs, ribs, sternum, head (skull), spine, and/or pelvis, not attributable to other causes
  • Requiring intravenous morphine or its derivatives
  • Informed consent obtained from the patient (or from a trusted support person, family member, or relative), or emergency inclusion procedure in cases where the patient is unable to consent and no trusted support person, family member, or relative is available

Exclusion Criteria:

  • Refusal to participate
  • Pregnant or breastfeeding patient
  • Administration of one of the interventional group treatments within 4 hours prior to inclusion
  • Intravenous morphine treatment for more than 24 hours
  • Patient already included in the study within the previous 3 months
  • Patient receiving long-term opioid therapy
  • Not affiliated with a social security scheme, or patient under State Medical Aid (AME)
  • Patient under legal protection measures (guardianship / family authorization with representation mandate / future protection mandate) or under supervised guardianship (curatelle)
  • Patient deprived of liberty
  • Participation in another clinical trial involving a drug
  • Participation in the PAMAVOC trial within the previous 3 months
  • Contraindication to standard VOC treatment:
  • Hypersensitivity to opioids
  • Opioid-induced hyperalgesia, defined by increased pain on nociceptive testing, topographic extension, or the onset of allodynia with increasing opioid doses
  • Renal impairment, defined as creatinine clearance ≤30 mL/minute
  • Hepatocellular impairment, defined as prothrombin time <40%
  • Impaired consciousness, defined as a Glasgow Coma Scale score ≤13/15

Exclusion from a Specific Intervention (randomization possible to other study arms):

  • Hypersensitivity to the active substance or to any of the excipients
  • Respective contraindications to nefopam, tramadol, ketoprofen, and ketamine, as described in their respective Summaries of Product Characteristics (SmPC)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Group 01 Control : Paracetamol + Morphine
Drug: Group 01 Control: Paracetamol + Morphine
Participants receive intravenous paracetamol and morphine via patient-controlled analgesia (PCA). In case of hyperalgic VOC, morphine dosage may be increased according to the treating physician's judgment
Experimental: group 02 : Paracetamol + Morphine + Ketamine
Drug: Group 02 Paracetamol + Morphine + Ketamine
Participants receive intravenous paracetamol and morphine via PCA. In case of hyperalgic VOC, low-dose ketamine may be added as a co-analgesic, off-label, according to the treating physician's judgment.
Experimental: Group 03 : Paracetamol + Morphine + Nefopam
Drug: Group 03 : Paracetamol + Morphine + Nefopam
Participants receive intravenous paracetamol, morphine via PCA, and nefopam. In case of hyperalgic VOC, morphine dosage may be increased according to the treating physician's judgment.
Experimental: Group 04 : Paracetamol + Morphine + Nefopam + Ketamine
Drug: Group 04 : Paracetamol + Morphine + Nefopam + Ketamine
Participants receive intravenous paracetamol, morphine via PCA, and nefopam. In case of hyperalgic VOC, low-dose ketamine may be added as a co-analgesic, off-label, according to the treating physician's judgment.
Experimental: Group 05 : Paracetamol + Morphine + Tramadol
Drug: Goup 05 : Paracetamol + Morphine + Tramadol
Participants receive intravenous paracetamol, morphine via PCA, and tramadol. In case of hyperalgic VOC, morphine dosage may be increased according to the treating physician's judgment.
Experimental: Group 06 : Paracetamol + Morphine + Tramadol + Ketamine
Drug: Group 6 : Paracetamol + Morphine + Tramadol + Ketamine
Participants receive intravenous paracetamol, morphine via PCA, and tramadol. In case of hyperalgic VOC, low-dose ketamine may be added as a co-analgesic, off-label, according to the treating physician's judgment.
Experimental: Group 07 : Paracetamol + Morphine + Ketoprofen
Drug: Group 7 : Paracetamol + Morphine + Ketoprofen
Participants receive intravenous paracetamol, morphine via PCA, and ketoprofen. In case of hyperalgic VOC, morphine dosage may be increased according to the treating physician's judgment.
Experimental: Group 08 : Paracetamol + Morphine + Ketoprofen + Ketamine
Drug: Group 08 : Paracetamol + Morphine + Ketoprofen + Ketamine
Participants receive intravenous paracetamol, morphine via PCA, and ketoprofen. In case of hyperalgic VOC, low-dose ketamine may be added as a co-analgesic, off-label, according to the treating physician's judgment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to resolution of vaso-occlusive crisis (VOC)
Time Frame: Up to 14 days after randomization.
Time to resolution of vaso-occlusive crisis is defined as the time from randomization to discontinuation of intravenous opioid therapy, measured in hours.
Up to 14 days after randomization.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intravenous Morphine Consumption
Time Frame: From admission to discharge, assessed up to 14 dayss)
Cumulative dose (mg) and mean daily dose (mg/day) of intravenous morphine.
From admission to discharge, assessed up to 14 dayss)
Transfusion Requirements
Time Frame: From admission to discharge, assessed up to 14 days
Number of red blood cell units transfused.
From admission to discharge, assessed up to 14 days
Intensive Care Unit Admission
Time Frame: From admission to discharge, assessed up to 14 days
Admission to intensive care unit during hospitalization.
From admission to discharge, assessed up to 14 days
Morphine-Related Adverse Effects
Time Frame: Within 3 months (+/- 15 days)
Constipation, sedation (impaired consciousness requiring opioid discontinuation or naloxone administration), vomiting, and secondary acute chest syndrome (new pulmonary infiltrate associated with a clinical sign such as fever, or a respiratory sign such as chest pain or dyspnea).
Within 3 months (+/- 15 days)
Length of Hospital Stay
Time Frame: From admission to discharge, assessed up to 14 days
Duration of hospitalization, measured in days
From admission to discharge, assessed up to 14 days
Hyperalgic Vaso-Occlusive Crisis
Time Frame: from randomization to discontinuation of intravenous opioid therapy Up to 14 days
Uncontrolled pain requiring morphine titration >1 mg/kg or total intravenous morphine consumption >2 mg/kg/24h.
from randomization to discontinuation of intravenous opioid therapy Up to 14 days
Refractory Vaso-Occlusive Crisis
Time Frame: From randomization to discontinuation of intravenous opioid therapy Up to 14 days
Visual analog scale (VAS) score >7/10 after administration of study treatments and a new morphine titration (1 mg/kg).
From randomization to discontinuation of intravenous opioid therapy Up to 14 days
Adverse Effects of Investigational Medicinal Products
Time Frame: Within 3 months (+/- 15 days)
Including nefopam (seizure); NSAIDs (acute kidney injury, KDIGO stage >0; gastrointestinal or other bleeding); tramadol (seizure, liver function abnormalities, impaired consciousness with GCS <14/15); ketamine (liver function abnormalities, hallucinations, impaired consciousness with GCS <14/15, venous access complications).
Within 3 months (+/- 15 days)
In-Hospital Mortality
Time Frame: Duration of hospital stay, assessed up to 14 days
Death occurring during hospitalization.
Duration of hospital stay, assessed up to 14 days
Unplanned Readmission
Time Frame: Within 3 months (+/- 15 days) after discharge
Unplanned hospital readmission within 3 months following the index hospitalization.
Within 3 months (+/- 15 days) after discharge

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Assistance Publique - Hôpitaux de Paris

Investigators

  • Study Chair: Ségolène GENDREAU, MD, PhD, Assistance public Hôpitaux de Paris

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 14, 2029

Study Completion (Estimated)

January 1, 2030

Study Registration Dates

First Submitted

July 28, 2026

First Submitted That Met QC Criteria

September 11, 2026

First Posted (Actual)

September 18, 2026

Study Record Updates

Last Update Posted (Actual)

September 18, 2026

Last Update Submitted That Met QC Criteria

September 11, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • APHP251244
  • 2026-527112-16-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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