The U.S. Food and Drug Administration has granted priority review to AbbVie‘s application seeking the approval of Imbruvica (ibrutinib) plus Gazyva (obinutuzumab) for patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL) who have not received prior treatments.

Priority review means the FDA will take action on the application faster than it would under standard review. It is typically granted to therapies that have the potential to significantly improve the treatment of serious conditions.

If approved, this will be the first chemotherapy-free combination containing a CD20 antibody approved for the first-line treatment of CLL/SLL.

“Our robust clinical research program with Imbruvica continues to reinforce the evidence for its use as an efficacious treatment option in CLL and SLL,” Danelle James, MD, head of Clinical Science at Pharmacyclics, an AbbVie company, said in a press release.

CLL and SLL are both slow growing non-Hodgkin’s cancers. They are considered the same disease, but while CLL cancer cells are found mostly in the blood and bone marrow, SLL cells are mostly in the lymph nodes.

Imbruvica, jointly developed by Pharmacyclics and Janssen, is an oral inhibitor of Bruton’s tyrosine kinase — a molecule needed for malignant B-cells to survive and multiply.

The medicine is already approved in the U.S. for six patient populations, including CLL/SLL patients — both as a front-line treatment and for those who failed one prior treatment.

Results from the Phase 3 iLLUMINATE trial (NCT02264574), on which the application submission is based, now show that replacing the chemotherapy chlorambucil with Imbruvica when treating CLL/SLL patients who had not received prior therapies significantly extended the time they lived without disease progression.

In the trial, patients were randomly assigned the standard of care — chlorambucil plus the CD20 antibody Gazyva, or a combination of Imbruvica and Gazyva.

Those assigned Imbruvica took three capsules of the medicine once daily until their disease progressed. Chlorambucil was also administered as an oral treatment. Gazyva was administered into the vein for six cycles.

The study’s primary objective was progression-free survival assessed by an independent committee. Secondary outcomes included overall response rate and minimal negative disease-negative responses — patients who have no signs of cancer in their bone marrow or blood.

While the trial met its primary goal, researchers have not yet disclosed the exact benefits of Imbruvica over chemotherapy. Janssen and Pharmacyclics are planning to present the data at a future medical meeting or publication.

“For the first time in CLL, results from iLLUMINATE have shown the potential benefits of using an Imbruvica-based, chemotherapy-free, anti-CD20 combination,” James said. “Since its initial approval five years ago, Imbruvica has received nine FDA approvals across six different diseases, and we remain committed to advancing new research to understand its full potential in blood cancers like CLL and SLL, as well as other difficult-to-treat diseases with unmet medical needs.”