Expert provides deeper insight into tocilizumab for giant cell arteritis
EXPERT ANALYSIS FROM THE WINTER RHEUMATOLOGY SYMPOSIUM
“This has implications for control of acute phase reactants,” the rheumatologist noted.
• Which patients with GCA should receive tocilizumab, and for how long?
The GiACTA finding that patients on 52 weeks of prednisone were only one-third as likely to be in continuous remission at 1 year is a deal breaker for the traditional therapy so far as Dr. Stone is concerned, he said in response to an audience question.
“I would treat almost everyone with tocilizumab right out of the gate, and I think the goal is to get them off concomitant prednisone fast. I think we can probably achieve that in less than the 6 months we used in GiACTA,” he said.
The ongoing second, open-label phase of the study will be informative regarding optimal treatment duration. In the meantime, the rheumatologist said, “I would treat patients for 12 months and then follow them to see what they need. We treat ANCA-associated vasculitis with rituximab and steroids, and some of them go into remission that lasts 5 years. I think some giant cell arteritis patients will be the same way, and others will flare right after you stop tocilizumab or maybe even while they’re still on it. Tocilizumab is not a cure, and these patients will still need to be followed closely.”
• What about intravenous tocilizumab, the far less costly option under Medicare?
The Food and Drug Administration will consider approval only for subcutaneous tocilizumab in GCA, since that what was used in GiACTA, although Dr. Stone is convinced based upon personal experience that the subcutaneous and intravenous formulations act identically. Roche/Genentech officials have told him they will pursue a separate approval process for the intravenous formulation.
• How about Takayasu’s arteritis?
It looks like a separate approval process, including a new study, will be required for this form of large-vessel vasculitis, Dr. Stone said.
• Intriguing baseline clinical features in GiACTA:
Mouth pain/jaw claudication was present in 34% of the GCA patients at enrollment.
“Jaw claudication is, I think, vastly underestimated as a very important symptom in giant cell arteritis. Of course, patients don’t say, ‘I have jaw claudication today, doc.’ You have to ask about it specifically. It’s not part of the ACR criteria, and I think it should be,” Dr. Stone said.
Also, cranial symptoms were present in only 79% of patients at enrollment.
“I think that’s important for physicians to know: One-fifth of patients had no cranial symptoms when they were enrolled in the study,” he continued.
Another key finding: Only 67% of GCA patients had a new-onset headache at enrollment.
“We think of headache as being so crucial in this disease, and it is important, but only two-thirds of patients in this trial had it,” the rheumatologist said.
Also, 62% of GCA patients had polymyalgia rheumatica at enrollment. More interestingly, 21% of patients with confirmed GCA had only polymyalgia rheumatica, with no cranial symptoms at all.
Dr. Stone reported receiving research grants from and serving as a consultant to Roche/Genentech, which sponsored GiACTA and markets tocilizumab for the treatment of rheumatoid arthritis and juvenile idiopathic arthritis.
