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
Cooperative Assessment of Late Effects for SCD Curative Therapies
Sickle Cell Disease is one of the most common genetic diseases in the United States, occurring in approximately 1 in 400 births. Approximately 100,000 individuals are diagnosed with SCD in the United States. Mortality for children with SCD has decreased substantially over the past 4 decades, with \>99% of those born in high resource settings, including the United States, France, and England, now surviving to 18 years of age. However, the life expectancy of adults with SCD is severely shortened. Dysfunction of the heart, lung, and kidney is directly associated with decreased life expectancy. With the variety of curative therapies that are now available for SCD, long-term health outcomes studies are time-sensitive. As of now, efforts to determine long-term health outcomes following curative therapies for SCD have been limited. Though curative therapies initially should provide a cure for symptoms of SCD, there is the risk of late health outcomes to consider. Defining health outcomes following curative therapy is essential to improve personalized decision-making when considering curative versus disease-modifying therapeutic options. The primary goal of this study is to determine whether curative therapies for individuals with SCD will result in improved or worsening heart, lung, and kidney damage when compared to individuals with SCD receiving standard therapy. The investigators will also explore whether certain genes are associated with a good or bad outcome after curative therapy for SCD.
Minimizing Toxicity in HLA-identical Sibling Donor Transplantation for Children With Sickle Cell Disease
This multisite prospective study seeks to determine if HLA-identical sibling donor transplantation using alemtuzumab, low dose total-body irradiation, and sirolimus (Sickle transplant Using a Nonmyeloablative approach, "SUN") can decrease the toxicity of transplant while achieving a high cure rate for children with sickle cell disease (SCD).