Immunotherapy Prompts “Remarkable Response” in Sarcomatoid Pleural Mesothelioma

Japanese doctors are reporting a remarkable response from the immunotherapy drug nivolumab in a patient with sarcomatoid pleural mesothelioma. 

Sarcomatoid pleural mesothelioma is a very rare form of a rare cancer. It accounts for about 10 percent of cases of malignant mesothelioma. 

This subtype is typically less responsive to standard treatments than the more common epithelioid variety. But researches at Kyushu Hospital in Fukuoka, Japan say nivolumab turned things around for their patient when the case looked hopeless. 

How is Sarcomatoid Pleural Mesothelioma DIfferent?

Malignant mesothelioma is a cancer of the linings around organs. Pleural mesothelioma grows on the pleural membrane that surrounds the lungs. 

There are three cell subtypes of mesothelioma. The three subtypes respond differently to mesothelioma treatments. Pathologists can tell the three types apart by their shape. 

Sarcomatoid pleural mesothelioma cells are slender ovals with large or even multiple nuclei. Because these cells are spindle-shaped, this type of mesothelioma is sometimes called spindle-cell mesothelioma. 

Sarcomatoid mesothelioma is an especially deadly form of the disease. This type grows and spreads faster than epithelioid mesothelioma. It is also harder to diagnose and more resistant to standard mesothelioma chemotherapy. 

Taking a Chance on Nivolumab

The newly-published Japanese case study appears in Respirology Case Reports. The authors say their 78-year-old male patient came in complaining of chest pain. A CT scan showed that he had a solid mass across the right side of his pleura. 

Pathologists diagnosed the patient with sarcomatoid pleural mesothelioma. At first, the patient received Alimta. Alimta is the only cancer drug approved for mesothelioma. It is the drug most patients start with. 

But the Japanese patient continued to go downhill. His mesothelioma tumor continued to grow and he got sicker. Doctors soon found new sarcomatoid pleural mesothelioma tumors in his chest.

It was not until they tried an immunotherapy drug called nivolumab (Opdivo) that the man’s condition began to improve. 

“After the nivolumab treatment, CT showed a significant reduction in pleural tumours with a marked improvement in symptoms,” writes author Kazuya Tsubouchi. 

PD-L1 Status Likely Drove Opdivo Response

The sarcomatoid pleural mesothelioma patient in the study tested positive for overexpression of PD-L1. PD-L1 is a protein that normally keeps the immune system from attacking healthy cells. If mesothelioma cells have high amounts of PD-L1, they are more likely to evade immune system attack. 

Immunotherapy drugs like nivolumab and pembrolizumab (Keytruda) block PD-L1. In patients with high levels of the protein, this can boost the body’s ability to fight mesothelioma. 

In the case of the Japanese patient with sarcomatoid pleural mesothelioma, nivolumab seems to be a lifesaver. “The patient has continued this treatment with sustained and remarkable effectiveness with good quality of life,” the report concludes. 

Source:

Tsubouchi, K, et al, “Remarkable response to nivolumab in sarcomatoid malignant pleural mesothelioma with high PD-L1”, February 14, 2020, Respirology Case Reports, Volume 8, Issue 3, https://onlinelibrary.wiley.com/doi/full/10.1002/rcr2.536