Cost-Effectiveness of Obinutuzumab in Combination with Bendamustine Followed by Obinutuzumab Maintenance versus Bendamustine Alone in Treatment of Patients with Rituximab-Refractory Follicular Lymphoma in Norway

To evaluate the cost-effectiveness of obinutuzumab in combination with bendamustine followed by obinituzumab maintenance (Obin-Benda) compared to bendamustine alone (Benda) in patients with refractory follicular lymphoma (FL) in a Norwegian setting. A three-state area-under-the-curve (AUC) model was developed. The states included were progression-free-survival (PFS), progressed disease (PD), and death. Each state had costs and utilities assigned to it. The pivotal phase III randomized controlled trial GADOLIN was used for clinical input in the model along with Norwegian cost estimates. The trial demonstrated that Obin-Benda improved overall survival (OS), with a hazard ratio (HR) of 0.67 (95% CI 0.47-0.96), and reduced the likelihood of progression or death (HR 0.52, 95% CI 0.39-0.69) compared to Benda. The model used EQ-5D data collected in the GADOLIN trial, with UK tariffs assigned to the EQ-5D scores. The total quality adjusted life-years (QALYs) for the patients on Obin-Benda were estimated to be 4.67, compared to 3.65 for Benda, while the total costs were estimated to be a,notsign98,849 and a,notsign51,570, respectively. Obin-Benda had an incremental gain of 1.02 QALYs compared to Benda, at an additional cost of a,notsign47,279. The estimated deterministic incremental cost-effectiveness ratio (ICER) was a,notsign46,438 per QALY gained, while the probabilistic ICER was a,notsign46,887 per QALY gained (95% CI a,notsign34,772-a,notsign59,443). The results were robust to changes in various sensitivity and scenario analyses. The cost-effectiveness threshold in Norway is not public, but based on previous decisions it is estimated to be up to approximately a,notsign89,000 per QALY (NOK 800,000). The results of the analysis indicate that obinutuzumab in combination with bendamustine followed by obinutuzumab maintenance may be cost-effective compared to bendamustine alone in Norway.