Brian Choi, PharmD, University of Arizona College of Pharmacy, Tucson, AZ, discusses results from a study evaluating the cost of adjunctive maintenance therapy with osimertinib in resected epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC), finding that it varies markedly across stages of disease.

These findings were presented at the virtual 2021 ASCO Annual Meeting.

Transcript:

My name is Briana Choi. I'm a PhD student at the University of Arizona Health and Pharmaceutical Outcomes program.

Today, we'll discuss the "Cost evaluation of osimertinib use as an adjunctive maintenance therapy in surgically resected EGFR-positive non-small cell lung cancer," which was presented at the Annual ASCO Conference 2021.

Before we jump into our study today, I wanted to point out that there have been more studies or several studies recently looking into immunotherapy as an adjunctive maintenance therapy in surgically resected cancer.

Last year, there was a study that was published looking into osimertinib use as an adjunctive maintenance therapy in surgically resected EGFR-positive non-small cell lung cancer.

Based off of that study, we built our economic models with two health state Markov model, including disease free survival and disease progression survival, or death.

This model was built with three-year time horizon, and from the US payer perspective with 3% discount rate. We conducted deterministic, or base case analyses, and probabilistic case analysis in order to confer any uncertainties.

The outcomes that we calculated were ICER, which is incremental cost-effectiveness ratio, and ICUR, which is incremental cost utility ratio. An ICER is equivalent to incremental dollar to gain one disease-free survival life year. An ICUR is equivalent to incremental cost to gain one DFS quality adjusted life year.

We built these models for different stages of EGFR-positive non-small cell lung cancer, which were stage IB, II, and IIIA.

Before we move on to the results section, I wanted to point out that for cost of osimertinib and placebo treatments, we included the cost of monitoring, as well as cost of adverse events. That might be the reason why you will see some cost added to the placebo treatment.

For stage IB, we had our cost difference between osimertinib and placebo to be around $500,000, while DFS life year was .4 years, and DFS quality difference was .26 years.

With these numbers, the ICER came out to be around $1.3 million and ICUR came out to be around $1.9 million. That means in order to gain one disease free survival life year, it would cost around $1.3 million in stage IB. For ICUR, it would cost around $1.9 million in order to gain one quality-adjusted life year.

For stage II, the cost difference between the two treatments came out to be around $503,000. DFS life year difference was .79 years, and DFS QUALY difference was .53 years. ICER came out to be around $636,000 and ICUR came out to be around $950,000.

For stage IIIA, the cost difference between the two treatments were around $322,000 and DFS life year difference was .127, while DFS quality difference was .18. ICER was around $1.2 million, when ICUR came out to be around $1.8 million.

For CEA curves, the cost effectiveness acceptability curves, for stage IB, with willingness to pay around $2.5 million, osimertinib had a 60% chance of being cost effective.

For stage II, around one million US dollars of willingness to pay, we had 70% chance of osimertinib being cost-effective.

For stage IIIA, we had around $4 million of willingness to pay and had 55% chance of having osimertinib being cost-effective.

With all these numbers, we concluded that the cost-effectiveness varies across the stages of resected EGFR positive non-small cell lung cancer. Among stage IB, II, and IIIA, osimertinib showed the greatest incremental benefit in stage II.

We were hoping that with our study, that we wanted to point out that the cost of adjunctive maintenance therapy still remains substantial. This needs to be looked into as part of our study in the future.

If you want to read more about this study, please feel free to visit ASCO 2021 Virtual Annual Conference or email me at bchoi@pharmacy.arizona.edu. Thank you.