Gene Editing: A Single Dose

People living with SCD have an abnormal type of hemoglobin, called hemoglobin S, in their red blood cells. Hemoglobin S causes red blood cells to sickle which can block blood flow causing pain and damage to the tissues and organs, and ongoing symptoms.

Gene Editing with EDIT-301

iv blood collection-02-01

Stem cells are collected from your bloodstream through your vein

These cells are sent to a lab to be edited using CRISPR gene editing technology, with the goal of creating healthy red blood cells that contain fetal hemoglobin

return blood-02-01

Your own, edited stem cells are put back into your bone marrow where they can potentially create healthy, non-sickled blood cells in your body

“This is an amazing time for the warrior community. Get all the information that’s out there to make the right decision for you and your family. I won’t let sickle cell be the boss.”

—Andre, living with sickle cell

RUBY Study Locations

Is gene editing different than gene therapy?

Gene editing is a type of gene therapy. Gene therapy includes addition, inhibition (stopping), editing, or replacement of a gene for disorders caused by a gene that is not working properly or is missing completely. Gene editing refers to cutting and modifying (editing) DNA (the genetic material in all cells) in your blood stem cells after they are collected from you.

Is gene editing the same as bone marrow transplant?

For SCD, bone marrow transplant (BMT) requires finding a suitable donor, while gene editing uses your own cells, eliminating the risk of graft-versus-host disease (GvHD). With BMT, patients may need drugs to suppress the immune system to avoid rejection, whereas these medications are not needed with gene therapy because patients are receiving their own modified cells.
With both procedures, the chemotherapy used to clear space for the new stem cells carries a risk of many long-term complications, which you should discuss with your doctor. Neither procedure impacts germ line cells, which means that SCD can still be passed on to biological children in the future.

Is RUBY a good fit for me?

To participate in RUBY, you must:

  • Be between 12 and 50 years old

  • Have a diagnosis of SCD (genotype HbSS, HbSβ0 thalassemia, HbS β+ thalassemia, HbSD, or HbSO-Arab)

  • Have had at least 2 severe vaso-occlusive crises each year for the past two years that required a hospital visit

  • Be capable of consenting to participate in the study

  • Be able and willing to follow the study requirements and schedule

RUBY might not be a good fit for me if:

  • Have an HLA-matched donor available
  • Have had a previous stem cell transplant or are not able to receive an autologous transplant (with your own cells)
  • Cannot tolerate any of the medications used in the trial
  • Are unable to receive red blood cell transfusion

The study doctors will explain all the requirements to you.

Participation in this study is at no cost to you, including travel, meals, and any required accommodation for you and a companion.

“I am a sickle cell warrior. I was born with this debilitating disease, and although my life has been filled with pain, I’ve battled through the pain to be a relentless advocate. I’m hopeful for what the future holds for sickle cell disease and the breakthroughs in treatment we’ll see from clinical studies. I won’t let sickle cell be the boss.”

—Dima, living with sickle cell

What to Expect in the RUBY Study

Participating in the RUBY study has 3 phases: about 6 months to get ready, 5 weeks to receive the new investigational medicine, and up to 2 years of follow-up visits. During this time, you will be treated by a study doctor, and will remain connected to your regular SCD doctor.

The RUBY study will take place in multiple locations across the United States and Canada.

study step 1-01

Part 1: Screening
Timing: about 6 months

This will include physical examination, blood tests, urine test, and imaging.

If you are eligible to participate in the study, you will be started on a tranfusion regimen.

Due to the conditioning procedure, your ability to have children may be affected so fertility preservation is offered during this phase if you would like to save sperm/eggs prior to treatment. The study doctor will discuss options with you. The study will pay for the consultation and collection, as well as sperm/egg storage for 15 years.

Collection of the blood stem cells from your blood using a process called apheresis (blood is drawn, processed to pull out blood stem cells, and the remainder returned to your body). This is a 3-day in hospital process for each collection.

Scientists will take your blood stem cells and edit them using CRISPR gene editing technology so that they can potentially make healthy red blood cells that contain fetal hemoglobin.

study step 2-01

Part 2: Administration
Timing: about 5 weeks

In the hospital you will receive chemotherapy for 4 days to clear out the existing bone marrow and “make space” for your edited stem cells (EDIT-301). An experienced team will take care of you during this time to manage any side effects.

In the hospital, your edited stem cells (EDIT-301) are given back to you like a blood transfusion.

You will remain in the hospital for about 4 weeks, after you receive your edited stem cells (EDIT-301). The study doctor and team will monitor you to see if your body starts to produce the new healthy blood cells on its own and check for any complications such as infections.

study step 3-01

Part 3: Follow-up
Timing: up to 2 years

During this period, you will continue to have scheduled visits with the study team to monitor for any affects on your issues or symptoms. This is important to check that the new healthy blood cells are continuing to be produced by your bone marrow and do their job and that you don’t have any issues or symptoms. They will continue to work with your regular SCD doctor during this time.

Common questions about participating in clinical studies

Clinical research studies, or clinical trials, look at an investigational medication to see if it is safe, and if it works to treat a specific disease. Clinical research studies are conducted by doctors who are responsible for the study participants’ study-related care.

Yes. Your regular doctor will be informed about your participation in the study and continue to see you for any non-study-related issues.

Participation in any clinical research study is completely voluntary, and participants may choose to leave the study at any time for any reason.

“Each of us living with SCD should consider participating in a clinical study. We are at an important time where many new technologies could offer the potential for a better life. These studies can be an important step toward learning more about sickle cell disease to help ourselves and our community.

Let’s do our part to see what we can unlock for SCD. I won’t let sickle cell be the boss.”

—Stephanie, sickle cell survivor

Connect with the RUBY team to discuss the study

It’s your call. If you are interested in learning more about the RUBY study, connect with us:


Talk to a real person from the Medical Affairs team at Editas. Call 617-401-9007


Send an email ([email protected]) and we can followup with you.


Click here to review the list to see if you or someone you love might be eligible for the RUBY study. Submit your information if you would like us to follow up with you.