Immune Checkpoint Inhibitors for Recurrent Mesothelioma: Early Adoption Gave Them Traction

A new report shows that doctors started using immune checkpoint inhibitors for recurrent mesothelioma at least two years before the practice was officially sanctioned. This early adoption gave ICIs traction to quickly become part of clinical practice. 

Immune checkpoint inhibitors block mesothelioma’s built-in resistance to immune system attack. They are among the most promising approaches to combating this intractable cancer. 

University of Pennsylvania researchers recently ran a retrospective study on immune checkpoint inhibitors for recurrent mesothelioma. The study looked at real-world mesothelioma patients at several different medical centers.

The researchers found that, even though the National Comprehensive Cancer Network (NCCN) did not revise it’s guidelines to include immune checkpoint inhibitors as a second-line treatment until 2017, doctors were using them to help patients as early as 2015. 

This “jumpstart” made it possible for these drugs to be quickly integrated into standard second-line mesothelioma treatment. 

The Need for a Second-Line Mesothelioma Treatment

Pleural mesothelioma is a hard-to-treat cancer of the tissue around the lungs. It causes few symptoms until it is in an advanced stage. Mesothelioma is also not very responsive to standard treatments. Chemotherapy and radiation may only extend life by a few months. 

Patients do not have many options if mesothelioma comes back after first-line treatment. Some studies suggest that more chemotherapy may help. But people with the most aggressive mesothelioma subtypes are least likely to respond to chemotherapy.

Immune checkpoint inhibitors for recurrent mesothelioma are most important for this patient population. Mesothelioma tumors produce proteins that make them unrecognizable to cancer-killing immune cells. ICIs “unmask” mesothelioma tumors to make them vulnerable to attack. 

Early Adoption of Immune Checkpoint Inhibitors for Recurrent Mesothelioma

Malignant mesothelioma is a frustrating disease for patients and doctors. Conventional cancer treatments often do not work. If cancer recurs, doctors can try other approved treatments, even if they are not part of the official treatment guidelines. 

NCCN guidelines added immune checkpoint inhibitors for recurrent mesothelioma in 2017. But the University of Pennsylvania study shows doctors starting using them before that, especially for nonepithelioid cases. These patients are less likely to respond to standard treatments. 

The new study included 310 patients with epithelioid mesothelioma and 116 with nonepithelioid mesothelioma. Patients received treatment between 2011 and 2019. A third of the patients received immune checkpoint inhibitors for recurrent mesothelioma. Two-thirds received more chemotherapy.

“ICI uptake began in early 2015 before the NCCN guideline revision and increased rapidly to 2019,” reports University of Pennsylvania researcher Roger Kim. “After the 2017 NCCN guideline revision, patients with nonepithelioid MPM histologic subtypes had more than 3 times the odds of receiving second-line ICI.”

It can take a long time for new treatments to catch on among clinicians. But Dr. Kim and his colleagues say the early and quick adoption of immune checkpoint inhibitors for recurrent mesothelioma reflects “prompt integration of scientific discovery into clinical practice.”

An estimated 2,500 Americans receive a mesothelioma diagnosis each year. 

Source:

Kim, R, et al, “Immune Checkpoint Inhibitor Uptake in Real-World Patients With Malignant Pleural Mesothelioma”, June 2021, JTO Clinical and Research Reports, https://www.jtocrr.org/article/S2666-3643(21)00047-3/fulltext