When the Food and Drug Administration approved avacopan (Tavneos) as an adjunctive treatment for severe, active antineutrophil cytoplasmic autoantibody (ANCA)–associated vasculitis (AAV) in October 2021, the oral complement C5a receptor inhibitor was hailed by its developer, ChemoCentryx, as a "new hope" for patients with the disease.
But avacopan's novelty as a new drug for the rare diseases granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), coupled with its approval as an adjunctive to standard therapy, including glucocorticoids, rather than strictly as a glucocorticoid-sparing agent as it was tested, has so far led to little reported real-world experience with the drug.
In the phase 3 ADVOCATE trial, the pivotal trial that served as the basis for avacopan's approval, 331 patients with active newly diagnosed or relapsing GPA or MPA received either avacopan or an oral prednisone taper over 20 weeks on a background of cyclophosphamide followed by azathioprine or rituximab. The results of the trial showed avacopan was noninferior to the group that received prednisone taper for remission at 26 weeks and superior to prednisone taper for sustained remission at 52 weeks, but the FDA was concerned that its complex design made it difficult to define the clinically meaningful benefit of avacopan and its role in the management of AAV.
The FDA noted that, in the avacopan arm of the trial, 86% of patients received glucocorticoids outside of the study protocol. Despite this, avacopan reduced the cumulative glucocorticoid dose over the trial's 52 weeks by nearly two-thirds, compared with the prednisone group (1,349 mg vs. 3,655 mg).
The data also indicate a higher sustained remission rate at 52 weeks in patients who received induction with rituximab, compared with cyclophosphamide. But trial did not include a maintenance therapy dose of rituximab and is thereby not a good comparison against the standard of care, the FDA said. (ADVOCATE began enrolling patients prior to the FDA’s 2018 approval of an expanded indication for patients with GPA or MPA who have achieved disease control after induction treatment.)
At the FDA's Arthritis Advisory Committee meeting in May 2021, committee members were split on whether to recommend avacopan for approval. The committee voted 9-9 on whether the ADVOCATE trial showed efficacy supporting approval of avacopan, 10-8 in favor of whether the drug's safety profile supported approval, and 10-8 in favor of the overall benefit-risk profile of avacopan for approval. But rather than give an indication to avacopan to reduce the use of glucocorticoids in adults with GPA or MPA, the agency approved avacopan as an adjunctive treatment for severe, active disease, noting in particular that avacopan "does not eliminate glucocorticoid use."
The European Union's marketing authorization for avacopan states its indication for use in combination with a rituximab or cyclophosphamide regimen for the treatment of adult patients with severe, active GPA or MPA and does not mention a role for reducing glucocorticoids. Avacopan will appear in forthcoming guidelines on management of AAV released by the European Alliance of Associations for Rheumatology.
In North America, the Canadian Vasculitis Research Network recently released an addendum to their guidelines on AAV specifically for avacopan, which includes recommendations to consider adding oral avacopan (30 mg twice daily) for induction of remission in patients with new or relapsing GPA or MPA who are also receiving cyclophosphamide or rituximab. The guidelines also recommend clinicians consider a glucocorticoid tapering schedule that aims for discontinuation at 4 weeks, and continuing avacopan for at least 1 year after induction therapy. The American College of Rheumatology guideline for AAV management, updated in 2021, acknowledges avacopan but did not consider its inclusion prior to FDA approval.
There have been few real-world studies of how patients with AAV are responding to avacopan, but recent studies from researchers in the Netherlands and in France have evaluated prednisone tapering and clinical outcomes.
Anisha B. Dua, MD, an associate professor of rheumatology at Northwestern University, Chicago, said those real-world studies "seemed to re-enforce the findings from the ADVOCATE study demonstrating the efficacy of avacopan in severe disease with steroid-sparing effects."
However, Carol Langford, MD, MHS, director of the Center for Vasculitis Care and Research at the Cleveland Clinic, emphasized caution is needed when drawing conclusions about avacopan use outside formal studies.
"We are all interested in what other settings this might be used. I think those are things that really require formal investigation to really try and understand better as far as through a study process," she said.
Prescribing experience with avacopan
A spokesperson from Amgen, which recently acquired ChemoCentryx, said in an interview that over 800 physicians in the United States have prescribed avacopan to patients with new or relapsing ANCA-associated vasculitis as induction or maintenance treatment, and physicians have reported outcomes consistent with the ADVOCATE trial.
Many rheumatologists are likely familiar with avacopan but are not used to prescribing it, said Lindsay S. Lally, MD, a rheumatologist with Hospital for Special Surgery in New York.
"Rituximab was approved for GPA and MPA a decade ago at this point. It was a drug that we as rheumatologists were used to using. We used it for other indications. Avacopan is a totally new drug, a new mechanism of action, so there's not a lot of extractable data that we have in terms of comfort with the drug, and so I think that's one of the biggest hurdles," she said.
Mehrnaz Hojjati, MD, a rheumatologist with Loma Linda (Calif.) University Health, said that, when the FDA approved avacopan, it was an "exciting time" in her practice. "I have used avacopan now in a handful of my patients with severe ANCA-associated vasculitis, and the results are similar to what [was] reported in the ADVOCATE trial."
Amgen offers help for clinicians in obtaining avacopan for patients, financial assistance for patients, and support in navigating insurance, which several rheumatologists noted was important for patients. Dr. Langford said the process of working with the manufacturer to get avacopan while insurance information is being processed has been "fairly smooth."
"Certainly, the ability to get a very rapid 30-day supply with the goal of trying to initiate this as early as possible in the disease process has been helpful," she said.
In Dr. Dua's experience, while there were "some glitches or difficulty for providers early on" in how to access and prescribe avacopan, since then "it has been much easier to obtain the medication with the first month being provided to patients free while the authorization process is managed."
Prescribing avacopan from inpatient pharmacies has been more challenging, she said. "The inpatient side is trickier because each hospital system has their own pharmacy system and regulations that have to be navigated. For outpatients, all the provider needs to do is fill out the start form available on their website, have the patients sign it, and then have it sent in."
Concerns about affordability, insurance approval
Another consideration is cost, with avacopan having an estimated price of $150,000-$200,000 per patient per year.
Dr. Hojjati noted that, while it is easy to prescribe, avacopan is hard to get approved through insurance. "We face the same challenge every time a new medication comes to the market on how to convince the payers to pay for it given higher prices," she said.
Rheumatologist Michael Putman, MD, MSCI, assistant professor of medicine at the Medical College of Wisconsin, Milwaukee, also acknowledged some difficulties in prescribing the medication. "The insurance companies have no interest in spending $150,000 on a drug that they know nothing about, and patients are a little hesitant to take it because it's just so new," he said.
While Dr. Lally said avacopan has not been difficult to get for patients with commercial insurance, reimbursement through Medicare has been problematic. "In many of the Medicare patients it has not really been a feasible option for them to be on the drug for the year of therapy."
Dr. Dua said almost all her patients with new or relapsing AAV who require induction are being prescribed avacopan, and that the medication is well tolerated. "The remission and ability to wean prednisone has really paralleled the findings from the clinical trial."
In her practice, Dr. Hojjati starts patients on avacopan immediately after discharge from the hospital after a major vasculitis flare requiring high-dose glucocorticoids. "Avacopan does not eliminate/replace GC [glucocorticoid] use but has a notable GC-sparing effect and assists in rapid tapering of the GC while treating our severe ANCA-associated vasculitis patients," she said.
Dr. Lally said her patients are tolerating avacopan well and hasn't seen any of the safety signals seen in the trial, including liver function abnormalities. She has treated about 20-25 patients with avacopan.
Dr. Putman noted that he has treated about five patients with avacopan but hasn't seen dramatic efficacy or side effects in his practice, compared with standard therapy.
Unanswered questions about avacopan
A key unanswered question with avacopan is the timeline for tapering glucocorticoids once patients start treatment. "I would like to see much more data on how prednisone is being tapered in clinical practice as well as outcomes in patients who are treated with the standard of care second dose of rituximab at 6 months," Dr. Dua said.
Dr. Lally noted she has tried to expedite the steroid taper in her patients. "That's really where I feel this drug is going to have most relevance, is getting it started early in active disease and getting patients off of the reliance on high doses of oral steroids. I have been able to see that in practice, and I do think ultimately that's going to lead to better outcomes and quality of life for these patients."
Of the rheumatologists Dr. Lally has spoken to about avacopan, there is "some confusion about what type of patients are appropriate, [and] how sick or not sick the patient needs to be."
Dr. Putman noted he is unsure which of his patients should be receiving avacopan. "I don't totally have a sense for where avacopan stands and how often we should be using it" outside of patients with severe disease. He added that the drug is still trying to find a niche because most patients with AAV who take rituximab and steroids get better without additional treatments.
"I think we do a pretty good job treating these diseases even in the preavacopan era. But it's really a matter of how to really optimize these outcomes, reduce damage, reduce steroid-related and treatment-related toxicity for our patients," Dr. Lally said.
Dr. Dua reported being a consultant and serving on advisory boards for ChemoCentryx; she was also a site principal investigator for the ADVOCATE trial. Dr. Hojjati reported being on the speaker's bureau for Amgen. Dr. Langford reported being an investigator in the ADVOCATE trial, and her institution received funding to conduct the trial. Dr. Lally reported being a consultant for Amgen on avacopan. Dr. Putman reported no relevant financial disclosures.
This story originally appeared on MDedge.com, part of the Medscape Professional Network.
Lead image: ChemoCentrix
Dr Anisha B. Due: M. Alexander Otto/MDedge News
Dr Carol Langford: M. Alexander Otto/MDedge News
Dr Mehrnaz Hojjati: Dr Mehrnaz Hojjati
Dr Michael Putman: Dr Michael Putman
Dr Lindsay S. Lally: Hospital for Special Surgery
Cite this: Experts Share Early Details Prescribing Avacopan for ANCA-Associated Vasculitis - Medscape - Mar 14, 2023.