Impact of tumour infiltrating lymphocytes-therapy for metastatic melanoma versus ipilimumab on patient outcomes and health care costs: An early stage health economic analysis.

Background: Metastatic melanoma has a poor prognosis with 10 year survival being < 5%. Standard therapy in the Netherlands is the effective but costly Ipilimumab. An emerging 1st line immunotherapy is Tumor Infiltrating Lymphocytes (TIL)-treatment, with response rates > 50% and expected survival rates of 25%-42% versus 45% (1yr) and 23.5% (2yr) for Ipilimumab. TIL is highly personalized, however complex and requests substantial upfront investments from the hospital in expensive lab-equipment, staff expertise and training. Therefore, an exploratory projection of its impact on patient outcomes and health care costs was made using health economic modelling.
Methods: A Markov decision model including three health states (stable disease, progressive disease and death) was developed to estimate the expected costs and outcomes (quality adjusted life years; QALYs) for TIL versus Ipilimumab in metastatic melanoma patients from a societal perspective over a life long time horizon. Data sources include a pilot study and published literature. Technical failures and treatment non-compliance were incorporated in the analysis to reflect real world effectiveness.
Results: TIL is expected to improve QALYs (+0.39) compared to Ipilimumab at higher incremental cost (+€12.416) with an ICER of €31.000/QALY. It has the highest probability of being cost-effective at WTP values of €30k/QALY (50% certainty) and higher, up to 90% certainty at a WTP of €80k/QALY. The model outcomes are most sensitive to changes in survival estimates.
Conclusions: Based on an exploratory analysis,TIL is expected to improve QALYs compared to Ipilimumab at lower incremental cost and has the highest probability of being cost-effective. To reduce decision uncertainty, a future clinical trial to investigate survival should be prioritized.