What the trial was testing
The RUBY Trial enrolled 45 patients with sickle cell disease. The study was sponsored by Editas Medicine and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was an early-stage trial — researchers are still confirming safety and getting an early look at how well the treatment works. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
27 of 28 patients had no painful crises after treatment.
New England Journal of Medicine · 2026 · NCT04853576
These findings — that had no painful sickle cell crises after a one-time gene editing treatment — were published in the New England Journal of Medicine and represent the headline result of the study.
Researchers tracked outcomes across 45 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with sickle cell disease, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
Reni-cel is not yet FDA-approved — this was a safety and early efficacy trial. Two other gene therapies (Casgevy and Lyfgenia) are already approved and may be available through your treatment center. Ask your hematologist about eligibility for approved gene therapies, and ask about any open gene editing trials.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open sickle cell disease trials
Promoting Utilization and Safety of Hydroxyurea Using Precision in Africa
Sickle cell anemia (SCA) is among the world's most common and devastating blood disorders, affecting more than 300,000 newborns per year. Most infants with SCA are born in the low-resource settings of sub- Saharan Africa, where an estimated 50-90% will die before 5 years of age due to lack of early diagnosis and appropriate care. Hydroxyurea is a safe and effective once-daily oral medication that has become the standard of care for the treatment of children with SCA in high-resource settings. There is now a growing body of evidence to support the safety and clinical benefits of hydroxyurea for the treatment of SCA in sub-Saharan Africa. The requirement for frequent laboratory monitoring, uncertainties about appropriate, most effective dosing, and the concern for hematologic laboratory toxicities, however, will continue to limit widespread hydroxyurea utilization and real-world effectiveness. The investigators have recently developed and prospectively evaluated an individualized, pharmacokinetics-guided hydroxyurea dosing strategy for children with SCA that has demonstrated optimal clinical and laboratory benefits with minimal toxicity. In this research study, the investigators aim to extend this precision medicine approach to Africa.
Molecular and Cellular Basis of Severe Forms of Dengue in Sickle Cell Patients
Dengue virus (DENV) belongs to the genus of Flavivirus transmitted by the mosquito Aedes aegypti and is responsible for an infectious disease associated with different forms and severities such as dengue hemorrhagic fever or shock syndrome. Several recent reports have shown that sickle cell patients exhibited an increased risk of developing severe forms of dengue episodes compared to non-sickle cell subjects. Furthermore, among major sickle cell syndromes, these studies suggest that SC patients are at the highest risk of death during these infectious episodes although this sickle cell syndrome is generally associated with a more moderate expression of sickle cell disease. However, the mechanisms involved remain unknown to date. The aim of the present study is to identify the molecular and cellular basis of this increased severity of dengue in SC patients. We hypothesize an exacerbation during DENV infection of the inflammatory response in SC patients compared to SS patients.