Its first findings were reported at the annual European Congress of Rheumatology, held online this year due to COVID-19.
“We have limited knowledge on the interrelationships between malignant and rheumatic diseases on both the clinical and molecular level, and we have a large unmet need for management guidelines in the case of the coincidence of both disease entities,” noted lead author, of the department of hematology, oncology, and rheumatology at University Hospital Heidelberg (Germany).
The TRheuMa registry – Therapy-Induced Rheumatic Symptoms in Patients with Malignancy – is one of three registries in a multicenter observational project exploring various contexts between malignant and rheumatic diseases. Over its first 22 months, the registry recruited 69 patients having rheumatic symptoms as a result of immune checkpoint inhibitor therapy or other cancer therapies.
The largest shares of patients had non–small cell lung cancer (38%) or melanoma (33%), Dr. Benesova reported. The immune checkpoint inhibitors most commonly received were pembrolizumab (Keytruda), nivolumab (Opdivo), and ipilimumab (Yervoy).
The immune-related adverse events usually presented with symptoms of de novo spondyloarthritis or psoriatic arthritis (42%), late-onset RA (17%), or polymyalgia rheumatica (14%). But 16% of the patients were experiencing a flare of a preexisting rheumatic and musculoskeletal disease.
Laboratory findings differed somewhat from those of classical rheumatic and musculoskeletal diseases, according to Dr. Benesova. Specific findings were rare; in particular, most patients did not have detectable autoantibodies. However, 76% had an elevated C-reactive protein level and 39% had an elevated soluble CD25 level. In addition, nearly all patients (96%) undergoing joint ultrasound had pathologic findings.
“Based on our experiences from interdisciplinary care together with our local oncologists, we have developed a therapeutic algorithm for rheumatic immune-related adverse events,” she reported, noting that the algorithm is consistent within this area.
The large majority of patients were adequately treated with prednisone at a dose greater than 10 mg (40%) or at a dose of 10 mg or less with or without an NSAID (40%), while some received NSAID monotherapy (14%).
“We have a growing proportion of patients on conventional or biological [disease-modifying antirheumatic drugs],” Dr. Benesova noted. “These are mostly patients with preexisting rheumatic and musculoskeletal disease or highly suspected de novo classical rheumatic and musculoskeletal disease under checkpoint inhibitor therapy.”
Patients with melanoma having a rheumatic immune-related adverse event had a better response to their therapy than historical counterparts who did not have such events: 39% of the former had a complete response, relative to merely 4% of the latter.
Only a small proportion of patients overall (9%) had to discontinue immune checkpoint inhibitor therapy because of their adverse event, and some of them may be eligible for rechallenge if their cancer progresses, Dr. Benesova noted.
“There is still a lot to be done,” she stated, such as better elucidating the nature of these adverse events [whether transient side effects or a triggering of chronic rheumatic and musculoskeletal diseases], the need for a defensive treatment strategy, and the advisability of closer monitoring of high-risk patients given immune checkpoint inhibitors. “We are aiming at solving these questions in the next few years,” she concluded.