Muhamad Alhaj Moustafa, MD, Division of Hematology and Medical Oncology, Mayo Clinic, Jacksonville, FL, discusses a real-world study comparing the utilization and cost-effectiveness of yttrium-90 ibritumomab tiuxetan vs bendamustine plus rituximab for the first-line treatment of patients with low grade follicular lymphoma (FL) and marginal zone lymphoma (MZL).

This study was presented at the 2021 ASH Annual Meeting.

Transcript: 

I am Muhamad Alhaj Moustafa. I'm an assistant professor at the Mayo Clinic in Florida.

I'm presenting the results of our retrospective cohort study titled utilization and cost-effectiveness of first-line yttrium-90 ibritumomab tiuxetan (Y-90) in low-grade follicular lymphoma and marginal zone lymphomas compared to standard of care, bendamustine plus rituximab, real-world experience.

Y-90 is a radioimmunoconjugate which targets B-lymphocyte antigen CD20 (CD20). It is the only commercially available radioimmunoconjugate agent. The US Food and Drug Administration approved it for relapsed and refractory low-grade non-Hodgkin lymphomas, as well as a consolidation therapy for follicular lymphoma patients who achieved BR or complete remission (CR) through first-line chemotherapy. 

It is not, however, approved as a standalone, first-line therapy in the treatment of low-grade non-Hodgkin lymphomas.

Y-90 is highly convenient treatment for patient due to short duration of treatment, as well as well-tolerated side effect profile. There has been no cost-effectiveness comparison comparing Y-90 to standard therapies, thus we performed a retrospective cost-effective analysis of Y-90 in our untreated low-grade follicular and marginal zone lymphomas.

In comparison to our cohort of historically matched, untreated low-grade follicular lymphoma and marginal zone lymphoma patients who are treated with standard chemoimmunotherapy, bendamustine plus rituximab.

We started by identifying patients who received Y-90 within the Mayo Clinic system between January 2003 and October 2019. We identified patients who received Y-90 for the treatment of follicular lymphoma and marginal zone lymphoma, then we excluded patients who received nonstandard Y-90 dose, patients who had follicular lymphoma grade 3, which represents a more aggressive disease.

We also excluded patients who received Y-90 consolidation after first-line therapy, as well as patients who had relapsed or refractory disease. We ended up with 51 patients who received Y-90 as a first-line therapy.

Similarly, we identified patients who received bendamustine plus rituximab in the first-line setting for the treatment of low-grade follicular lymphoma and marginal zone lymphoma. Then we excluded patients who received nonstandard BR combination on clinical trials, patients who had bone marrow involvement more than 25%, as this is a requirement for Y-90 treatment.

We also excluded patients who had no bone marrow biopsy prior to treatment, and patients who were hospitalized for urgent need of treatment at diagnosis were also excluded as those are not typically offered Y-90. Patients who had concurrent diagnosis of high-grade lymphomas were also excluded from this study.

Finally, we ended up with 92 patients who were included in that comparator arm.

Our whole cohort consisted of a total of 143 patients: 64% received BR and 36% received Y-90. However, it's important to note that there was significantly more bulky disease in the comparator arm, as well as high Follicular Lymphoma Interntional Prognostic Index (FLIPI) score.

The median follow-up from the time of therapeutic administration for the Y-90 group was 5.3 years with one death in the cohort. The median follow-up for the BR group was 4.7 years with 6 deaths in the group.

The overall response rate to treatment was 100% for the Y-90 group, with 94% achieving complete remission, while the overall response rate for the bendamustine plus rituximab group was 98% with 95% achieving CR.

Rituximab maintenance was utilized in 33% of the BR patients, compared to only 6% in patients who received Y-90.

We utilized inverse propensity weighting to account for clinical and disease characteristics that could cause imbalance between the two groups. Those characteristics included age, sex, body mass index (BMI), stage, bulky disease, FLIPI score, and meeting one of the Groupe d'Etude des Lymphomes Folliculaires (GELF) criteria.

After utilizing inverse propensity weighing, the 5-year progression-free survival was 76% for the Y-90 group, as compared to 75% for the BR group. Basically, they were similar.

Finally, we evaluated the average treatment effect of Y-90 compared to the BR on utilization outcomes. Y-90 patients required an average of 4.5 clinic visits less within the first year after treatment compared to the BR group, and Y-90 patients had an average of 10 days less of therapeutic use days compared to the BR group.

Patients in both groups had similar admission rates to the hospital. However, when patients were admitted to the hospital within the first year after treatment, those who received Y-90 spent an average of 1.5 less days in the hospital when compared with the BR group.

The overall use of growth factors was also 40% less in the Y-90 group when compared with the BR group, and the therapeutic cost of induction of Y-90 was 54% less in the Y-90 group compared with that of six cycles of bendamustine plus rituximab.

In summary, Y-90 is a very convenient and cost-effective treatment for low-grade untreated follicular lymphoma and marginal zone lymphoma. This is especially important in situation that requires less contact with the health system, with decreased number of therapeutic days, clinic visits, use of growth factors, and number of hospitalization days.

The cost of the therapeutic agents and their administration was also significantly lower for the Y-90 group compared to the BR, which could help reducing the burden on the health system.

Thank you so much.