NCI Opens New Immunotherapy Clinical Trial for Mesothelioma

The National Cancer Institute has opened a promising clinical trial aimed at increasing the effectiveness of immunotherapy treatment for patients with unresectable malignant mesothelioma.

This latest study involves combining LMB-100, a manmade protein designed to kill cancer cells, with ipilimumab, an immunotherapy drug recently approved for use by the U.S. Food and Drug Administration. Ipilimumab is also known by the brand name Yervoy.

Although immunotherapy has worked well with some cancers, its effectiveness in treating mesothelioma has been selective and has lacked sustainability.

This new study combination has been especially effective in earlier laboratory testing, leading to the phase I clinical trial for both pleural and peritoneal mesothelioma.

“We know it works in mice,” principal investigator Dr. Raffit Hassan told The Mesothelioma Center at Asbestos.com. “Whether it works in humans, only time will tell. We’ll have to see. The goal is making these tumors more responsive to immunotherapy.”

Hassan is chief of the Thoracic and GI Malignancies Branch at the National Institutes of Health Clinical Center in Bethesda, Maryland, where the trial has begun. He has been instrumental in recent mesothelioma treatment advances.

Combination Could Offer Viable Second-Line Option

The trial is designed for patients with inoperable disease, where both standard chemotherapy and immunotherapy were used earlier before tumor growth returned. It is for confirmed cases of epithelial or biphasic mesothelioma, the most common types of mesothelioma.

“For patients today, there really is no, or very limited, options after chemotherapy and immunotherapy have failed,” Hassan said. “This study offers a reasonable chance of benefit. It would be nice to see if these patients again respond to immunotherapy.”

The FDA approved Opdivo and Yervoy, an immunotherapy combination, for first-line treatment of pleural mesothelioma in 2020. It was the first new systemic approval in more than 16 years. However, it only increased the median overall survival time from 14.1 months to 18.1 months, when compared to standard chemotherapy.

LMB-100 Trial Follows Earlier Study

This latest mesothelioma trial is building on an earlier study at the National Cancer Institute involving pembrolizumab (Keytruda), another immunotherapy drug with a different way of delivering LMB-100.

The earlier trial used systemic delivery. This latest trial involves an intratumor injection of the drug, a novel method that will be watched closely for its potential to better stimulate a more durable immune system response.

LMB-100 works by targeting mesothelin, a tumor-associated antigen that is found highly expressed on the surface of many different types of tumors, including pancreatic, ovarian, lung and mesothelioma.

“In mice, you can completely get rid of the tumors with this delivery. Not only the ones injected, but those not injected,” Hassan said. “It’s one reason for this clinical trial to see if we can achieve the same in patients.”

Researchers Test Safe Dosage Levels   

Patients in the trial will receive the LMB-100 injections into their tumors on days 1 and 4 for up to two 21-day cycles. Those will be combined with up to four doses of ipilimumab systemically.

Through the trial, researchers expect to identify the safest and best dosage levels for both LMB-100 and ipilimumab.

Ipilimumab is known as a checkpoint inhibitor immunotherapy, which helps the body’s immune system attack cancer cells.

LMB-100 was designed originally to broaden immunotherapy effectiveness. Dr. Ira Pastan, an NCI scientist, led the drug’s development.

“There is hope on the horizon – more options today for patients with mesothelioma than there were a few years ago,” Hassan said. “We’ll just have to see where this goes. Progress is being made.”