A study conducted by researchers at MD Anderson Cancer Center demonstrated acceptable toxicity and anti-tumor activity in patients with four types of advanced, hard-to-treat rare cancers. Study findings were published in the March 17 online issue of the Journal for ImmunoTherapy of Cancer.
The open-label, phase II study followed 127 patients who had advanced rare cancers: squamous cell carcinoma of the skin, carcinoma of unknown primary, adrenocortical carcinoma, and paraganglioma-pheochromocytoma. All patients had tumors that had progressed on standard therapies.
The primary objective of the study was to find the proportion of patients who were alive and progression-free at 27 weeks on treatment with pembrolizumab. The median non-progression rate at that time was 28% for 127 patients with advanced rare cancers. Complete response, partial response or stable disease after four months was observed in 38% of the patients. Non-progression rates for each cancer group were: 36% for cSCC, 33% for CUP, 31% for ACC, and 43% for paraganglioma-pheochromocytoma. Treatment-related adverse events occurred in 52% of patients, with the most common side effects being fatigue and rash, with six deaths reported that were unrelated to treatment.
“Our findings that pembrolizumab has a favorable toxicity profile and anti-tumor activity in patients with these rare cancers supports further evaluation in these populations,” Aung Naing, associate professor of Investigational Cancer Therapeutics, said in a statement. “Finding solutions for treatment is vital given that patients with advanced rare cancers have poor prognosis and few treatment options.”
CUP is a type of cancer in which the primary cancer site is not always known, but has spread to other areas within the body, while ACC occurs when malignant cells form in the outer layer of the adrenal glands.
Paraganglioma-pheochromocytoma are tumors formed in nerve-like cells near the adrenal glands and near blood vessels or nerves in the head, neck, chest, abdomen, and pelvis.
