Good day, thank you for standing by. Welcome to the Kiniksa Pharmaceuticals Q3 conference call. At this time, all participants are on a listen-only mode. After the speaker's presentation, there'll be a question-and-answer session. To ask a question during that session, you will need to press star one on your telephone. If you require any assistance during the call, please press star zero. I would now like to hand the conference over to your speaker today, Ms. Rachel Frank. Ms. Frank, you may begin.
Thank you, operator. Good morning, everyone, and thank you for joining Kiniksa's call to discuss our Q3 2021 financial results and our recent corporate and pipeline activity. A press release highlighting these results can be found on our website under the Investors and Media section. As for the agenda, our Chief Executive Officer, Sanj K. Patel, will start with an introduction. Ross Moat, our Head of Commercial, will provide an update on the ARCALYST commercial launch. Eben Tessari, Kiniksa's Chief Business Officer, will follow with a brief pipeline review. Mark Ragosa, our Chief Financial Officer, will review our third quarter 2021 financial results. Finally, Sanj will return for closing remarks and to kick off the Q&A session for which John Paolini, our Chief Medical Officer, will also be on the line.
Before getting started, please note that we will be making forward-looking statements today that are subject to risks and uncertainties that may cause actual results to differ materially from these statements. A review of such statements and risk factors can be found on this slide, as well as under the caption "Risk Factors" contained in our SEC filing. These statements speak only as of the date of this presentation, and we undertake no obligation to update such statements except as required by law. With that, I will turn it over to Sanj.
Thanks, Rachel. Good morning, everyone. I'm happy to review our Q3 2021 results today. We continue to make tremendous progress in bringing ARCALYST to patients in need, and we're also executing across our portfolio of clinical stage product candidates. I'm delighted to report that net revenue for ARCALYST for the Q3 of 2021 was $12.1 million. As expected, recurrent pericarditis was the major growth driver for the ARCALYST Q3 sales. Ross will cover our commercial performance in more detail in a moment. We are very pleased with the implementation of our targeted commercial strategy. This includes broad physician and patient adoption and the viable reimbursement conditions. These core elements are what's driving recurrent pericarditis sales and underscore the significant need for ARCALYST.
Additionally, we remain focused on building the maximum value across our portfolio of clinical-stage product candidates, and these are mavrilimumab, vixarelimab, and KPL-404, which is our CD40 program. We continue to expect data in Q1 of 2022 from our phase III trial of mavrilimumab in COVID-19-related ARDS, and Eben will highlight the potential opportunity in this patient population a little later. We continue to be energized by our progress across the entire portfolio, and we believe that we're well-positioned for longer-term growth. I'll now turn it over to Ross to discuss our commercial performance in more detail. Ross.
Thank you, Sanj. We're thrilled to report that Q3, on Q2 of launch, continued with very positive momentum and ended in great shape with a net revenue of $12.1 million. This represents a 57% quarter-on-quarter growth, and as anticipated, recurrent pericarditis was the major growth driver in Q3. Revenue from CAPS and DIRA indications remained stable, and as expected, the one-off inventory build that we saw in the launch quarter did not repeat in Q3. Therefore, recurrent pericarditis demand grew from a base of approximately one-third of the $7.7 million in Q2 to more than three-quarters of the $12.1 million of revenue in Q3. We are delighted with the growth rate. It represents continued uptake and adoption of ARCALYST from physicians, payers, and patients in this previously unmet and debilitating ultra-inflammatory cardiovascular disease.
Taking into consideration the early launch trends, we are providing a Q4 net revenue guidance of between $16 million and $17 million. On slide 8, I will dive into more detail on the drivers behind the recurrent pericarditis growth. We're very pleased with the continued broad physician adoption. At the end of Q3, there were more than 200 unique prescribers who had written ARCALYST for recurrent pericarditis since launch. This is more than double the number we reported in Q2, demonstrating rapid growth in the breadth of awareness and prescribing of ARCALYST. We're also starting to see an increase in prescribers who are writing for multiple recurrent pericarditis patients. Since launch, the commercial team has engaged with around 4,000 physicians, representing more than 80% of the initial target accounts.
Furthermore, while we hear many other companies are continuing to engage remotely, we're achieving in excess of 80% of these prescriber interactions face to face. This highlights the favorable access we have to our target accounts, as well as the eagerness of many physicians to learn about ARCALYST. On the payer side, we continue to see that more than 90% of all completed recurrent pericarditis patient enrollments were approved for coverage. We're also pleased and encouraged to report that we have achieved broad access through finalized payer policies for our target population, with greater than 190 million lives in the U.S. now having favorable coverage in place. This is a higher and quicker coverage than our pre-launch expectations and allows physicians the confidence of gaining access when prescribing for their patients.
As previously stated, we continue to expect that almost all of the remaining payers will update their coverage policies within one year of launch. Additionally, while we're still too early to provide definitive updates on duration of therapy, it's important to state that so far two-thirds of the ARCALYST prescriptions for recurrent pericarditis were written for 12 months of therapy. This is an excellent marker for how specialists are thinking about how long to treat a patient with recurrent pericarditis. However, ultimately, duration of treatment will depend on the duration of the underlying disease as well as the patient's willingness to remain on therapy and the payer approval duration. When it comes to compliance, we're generally seeing that patients receive refills on time and that almost all of the patients who initiated ARCALYST in Q2 were still on therapy at the end of Q3.
On slide nine, I would like to highlight how we're interacting with patients and healthcare professionals through our new marketing campaign. We recently launched our full promotional breakthrough campaign, which we believe reflects the strength of the data behind ARCALYST in recurrent pericarditis and the desire for patients to return to their normal lives. We truly believe ARCALYST is becoming recognized as a breakthrough treatment that provides a targeted approach to the underlying driver of this disease. Through our disease education initiatives, promotional local and national webinars, social media, and advertising, we have built a database of approximately 2,000 patients and caregivers across the U.S. who have opted in to receive further education on the disease and treatments.
In recent weeks, we initiated a tailored communication plan to this patient group designed to provide targeted information on recurrent pericarditis, depending on the stage in their journey, and to give them the tools and resources to ask their physician about ARCALYST. Around 75 patients from the database are currently on ARCALYST treatment, and we anticipate this campaign will help to reach more patients in coming quarters. Moving to slide 10, I wanted to share some examples from the patient's perspective on recurrent pericarditis and ARCALYST. Recurrent pericarditis is an incredibly painful and debilitating disease, and we have remained completely focused on the fact that patients are in need, and ARCALYST is the first and only FDA-approved drug for this disease. These quotes directly from patients are an example of why the Kiniksa team are so focused and driven to secure a successful ARCALYST launch.
We are here to support patients to break through from this disease and get back to their normal lives. We're delighted with the Q3 results, and we now have two strong foundational quarters from approval, and we look forward to continuing to deliver for patients in Q4 and beyond. Eben, over to you.
Thanks, Ross, and good morning, everyone. I will provide a brief overview on where we stand with our three clinical stage programs. Starting with vixarelimab, we're currently enrolling a global randomized placebo-controlled phase IIb dose-ranging trial in prurigo nodularis, testing 3 different once-monthly dosing regimens. Vixer is a first-in-class mechanism that targets OSMRβ, which mediates the two key cytokines implicated in pruritus, hyperkeratosis, and fibrosis. The primary efficacy endpoint is change in Worst-Itch NRS at week 16, and we expect data from this trial in H2 of 2022. For KPL-404, we plan to initiate a phase II proof-of-concept trial in rheumatoid arthritis by the end of this year.
RA is a disease where dose response has been well-characterized, and this 12-week trial in RA patients is designed to provide not only PK characterization but also an early signal of efficacy with chronic administration in a well-described patient population. The results from this study may also enable optionality to evaluate the therapeutic potential of KPL-404 across a range of autoimmune diseases with pathologies believed to be mediated by CD40 signaling. Finally, we're encouraged by the broad potential utility of mavrilimumab, which has demonstrated previous positive clinical data across multiple indications, including giant cell arteritis and COVID-19-related ARDS, which we'll walk through in the next two slides. Turning to slide 13, we believe the treatment of hospitalized patients represents and will remain a significant market opportunity.
Since the onset of the pandemic, and despite over 175 million of the U.S. population being fully vaccinated, the rate of hospitalizations has remained multiple-fold above the historical average of hospitalizations for influenza, which are around 400,000 cases per year on average. We've seen the limitations of vaccines in terms of hesitancy and availability, resulting in the emergence of variants and the resulting upsurge in hospitalizations even among vaccinated individuals. The therapeutic options for patients once hospitalized with pneumonia are limited. As evidence of this, the last six months have seen the second-highest surge of hospitalizations since the pandemic began, and that's in the context of between 100 million and 175 million Americans having been fully vaccinated.
While we hope that vaccination, vaccinations and antivirals may reduce some of the hospitalizations to come, we fully expect that the rate will remain significantly higher than the seasonal influenza ARDS rate for several years to come, both in and outside the U.S. With that market context and turning to slide 14, I wanna highlight mavrilimumab in our phase III trial in COVID-19 ARDS, which is the next program for which we expect to have data. As shown here on this slide, based on our phase II data, we believe mavri is differentiated and a potentially best-in-class therapeutic for patients with COVID-19-related ARDS. As plotted here, either looking at absolute or relative mortality benefit versus other published data in the hospital setting, mavrilimumab could end up being positioned strongly in the market if our phase II data are confirmed in phase III.
In April, we reported data from the phase II portion of the study showing that day 29 mavrilimumab reduced the risk of death by 61% in hospitalized non-mechanically ventilated patients versus placebo. In August, we reported that overall survival in this same non-mechanically ventilated cohort of patients was carried out through day 90. Those results demonstrate the persistence of the substantial mortality reduction over time, thus confirming and extending the previously reported day 29 data. This effect of prolonged outcomes is also consistent with the prolonged pharmacokinetics of the single administration of mavrilimumab, which had been given on day 1. Currently, we're focused on completing our phase III trial of mavrilimumab in COVID-19-related ARDS, and we expect data in Q1 of 2022. With that, I'll now turn the call over to Mark to cover the third quarter financials.
Thanks, Evan. Good morning, everyone. Today, I'm gonna walk through our financial performance for Q3 of 2021 and review our guidance. You can find our detailed financial information in today's press release, and I'd like to call your attention to a few items. First, Q3 revenue was $12.1 million, driven primarily by sales of ARCALYST and recurrent pericarditis, which more than doubled sequentially, as well as stronger than anticipated initial market access with greater than 190 million lives already covered in the United States. Second, based upon execution to date and strong third quarter sales, we expect total ARCALYST net revenue of between $16 million and $17 million in Q4 of this year.
Third, as a reminder, Kiniksa is responsible for the sales and distribution of ARCALYST for the approved indications in the United States, including CAPS and DIRA, and evenly splits profits on sales with Regeneron. When profitable, collaboration profit sharing will be reflected as a separate line item within operating expenses. In Q3 of 2021, we did not make a collaboration profit-sharing payment. Lastly, net loss for Q3 of 2021 was $30.5 million, compared to $43.8 million for the same period last year, and we ended Q3 of 2021 with cash reserves of approximately $200 million, which we continue to expect to fund our current operating plan into 2023. With that, I'll turn the call back to Sanj for closing remarks.
Thanks, Mark. Turning to the last slide, which is slide 18. At Kiniksa, we are focused on building the maximum value across our portfolio. It's a very exciting time for the company. We continue to maintain a strong start with the launch of ARCALYST in recurrent pericarditis. The positive feedback we continue to receive from physicians and patients validates the need for this therapy. As I mentioned previously, we are energized by our progress across our portfolio, and we believe that we're well-positioned to execute throughout this year and beyond. We are encouraged by the broad utility of mavrilimumab, seen to date in COVID-19 and GCA, vixarelimab in prurigo nodularis, and KPL-404's potential in a range of autoimmune diseases.
Importantly, as Mark mentioned, we are very well capitalized, and we have cash reserves of $200 million that are expected to fund our current operating plan into 2023. With that, I wanna thank you all for your time today. I'll turn the call back to the operator.
Thank you, sir. As a reminder, to ask a question, you'll need to press star one on your telephone. To withdraw your question, please press the pound key. Stand by as we compile the Q&A roster. Our first question comes from Anupam Rama of JP Morgan. Your line is open.
Hey, guys. Thanks so much for taking the question and congrats on the quarter. You guys noted that 2/3 of prescriptions for ARCALYST are being written for 12 months. For the other 1/3, what type of duration are the prescriptions being written for? And are there any trends on the patient type that are getting a 12-month prescription versus another duration prescription? Thanks so much.
Ross, do you wanna take that?
Yeah, very happy to. Hi, and, thanks very much for the question. Nice to speak to you again. Yeah, so two-thirds of the patients had prescriptions for 12 months duration, which is, you know, we were very pleased to see that. It gives us a good insight into how physicians are thinking about the duration of therapy. For the remaining one-third, I mean, it was obviously, you know, not 12 months. It really comes down to physicians and how they are expecting to see patients again in their follow-up clinics. Outside of those two-thirds, you know, there will be prescriptions there that will be for 3 months or be for 6 months.
That doesn't necessarily kind of interpret into what they expect the duration of therapy to be, but could moreover be, you know, expecting to see the patients again, kind of reassessing from the baseline and really understanding the treatment duration on from there, and just making sure that they have that follow-up with the patient. Particularly as physicians are reasonably new to ARCALYST, many of these physicians are prescribing for the first time, so they might want a kind of a closer patient follow-up than may happen in the longer term.
Hopefully that answers that part of it. In terms of patient trends and patient types, I think at the moment it is such low numbers in the early stages of launch that it's difficult to kind of correlate, you know, which patients are getting what disease, which duration. I think that's kind of difficult to answer right now. I'm not sure there is a correlation there. But broadly speaking, we see two different types of patients. We see patients coming through that are clinically stable, so they're patients either coming from our long-term extension study, or they're coming from chronic steroids. And then we see patients that are acutely symptomatic, really suffering from the disease, and really seeking a targeted treatment.
That's kind of two main categories of patient cohorts that we're seeing. Of course the duration question, even though that's what's being prescribed, doesn't necessarily mean that that's what the actual eventual duration is gonna be. The duration of treatment ultimately will depend on the duration of the disease, and also, you know, where patients are in the disease course, as well. What we do know is that continued treatment results in continued treatment response. If you stop patients too early into therapy, there's always the risk that they will rebound and suffer from symptomatic disease once again.
We probably need more time to kind of tell what the actual eventual average duration is gonna be in the midterm and look forward to being able to report on that in time to come.
Thanks so much for taking our question.
Thank you. Our next question comes from Paul Choi, Goldman Sachs. Your line is open.
Thank you very much for taking our questions, and let me add my congratulations on the quarter as well. My first question is on commercial. With regard to, as you go in to see doctors here, can you maybe just comment on, you know, what factors are being cited as, you know, potential hesitancy to get RP patients onto ARCALYST? Is it primarily just access or reimbursement, or are they looking for any other particular pieces of information or clarifications?
I'm happy to take that question as well. Hi, Paul. Thank you very much for that. In terms of the headwinds or barriers or hesitancy there, for patients to prescribe, I mean, this is for doctors to prescribe, this is just a, you know, still relatively early on in the launch. It will be a first experience for many of the physicians, and I think that probably goes into the previous comment about wanting to see patients again and follow up and see how they're doing on the early stages of treatment. Outside of that we don't necessarily see hesitancy from healthcare professionals. It's just more of waiting to see the appropriate patients.
Of course, this is a rare disease and a flaring disease, so we will need to do a lot of education and make people aware of this targeted treatment and the first-in-class treatment that's approved now for recurrent pericarditis. You know, we're having very successful meetings with physicians. When patients do come through, we think we'll continue to see the uptake prescribed. Access and reimbursement is always a question for physicians, particularly when a drug is reasonably new on the market. What we've seen so far in the payer side of things is really quite successful approval rates. As we mentioned, we still have more than 90% of all completed cases approved.
Now that we have payer coverage in place much more broadly now with more than 190 million lives covered across the U.S., hopefully that will also provide a lot of confidence for physicians as well as speed up the time through to approval and get patients onto therapy as quickly as possible.
Okay. Thanks, Ross. That's helpful. I think this question is on the pipeline, so maybe for Evan. Just, I don't know if I missed it on the slides here, but can you maybe just update us on, you know, what is the status of the phase III plans for Mavri in GCA, you know, timing and trial initiation and so forth, and trial design? Also, could you maybe help us, you know, understand how you're thinking of, you know, potential development here and thinking about the trial in the context of Novartis recently announcing positive phase II data for their IL-17 secukinumab? Thank you very much.
Thanks, Paul. This is Sanj. Maybe, Chris, probably better directed to John, but I'll make a few comments. Obviously we're very pleased with the phase II results that we had in GCA and really showed a potential for true differentiation there. We've not disclosed or commented on our sort of next steps immediately in terms of timing for GCA, but John can give you an idea as to what we've disclosed in the past and potential trial designs. John, over to you.
Sure. Happy to do that. Nice to talk with you again. With regard to the design, I think what we've discussed before and what we said we've discussed with the agency is that with the positive phase II results in the trial, it was a 26-week trial that included both new onset and relapsing refractory patients. That the design of the phase III, you know, it could be as simple as a single phase III clinical trial being pivotal for moving forward with a BLA. The idea there is to make sure that we have replication of data as well as a sufficient safety database with the 52 weeks of exposure according to ICH guidelines.
Regarding the secukinumab data, yes, we're aware of the data and the recent presentation of the data. You know, they do appear to be a positive result, you know, which is always good for patients. We believe that mavrilimumab by targeting both TH1 as well as TH17 driven disease, especially the importance of GM-CSF with gamma interferon, which is a TH1 cytokine in the pathophysiology of the disease, could still be differentiating for mavrilimumab. Of course, that will depend upon the clinical results, but we're confident in our program going forward.
I think we're having some technical difficulties there. Shall we go to the next question, operator? You still there?
Yes. Thank you.
Yep. Great.
Next we have Geoff Meacham of BOA. Your line is open.
Good morning, everyone. This is Jason on for Geoff. Thanks so much for taking our question and for the great quarter. A question on the payer dynamics for rilonacept, if you will. Can you help us understand kind of the current gross to net and where things are moving or at least evolving? You know, to what extent was there patient assistance and how is that changing, and what are your expectations moving forward? Then, if I may, on the patient disposition, you know, were the majority of patients that were treated, were these patients who were transitioning over from the clinical studies, were they sort of in the wings? You know, were these heavily refractory patients, somewhat new? Any sort of color there would be very helpful. Thanks so much.
Jason. Hey, this is Sanj. Maybe I'll make an opening comment and then Ross or Mark can jump in. Obviously we're still in the early stages of launch, and as you can expect, gross to net is quite fluid at this stage. We aren't providing any specific guidance or analysis on that. I'll hand over to Ross and see if he wants to be a bit more effusive, but that's where I'm at.
Yeah. I think you're absolutely correct, Sanj. We're not providing any specific guidance kind of moving forward on the gross to net side and free goods. I guess the commentary that I can provide on that to help a little bit is that in Q3, we did benefit from a stronger than expected commercial payer mix, meaning a higher percentage of patients in the commercial insurance payer bucket opposed to government insurance leading to less statutory discounts. That was some favorability in Q3 related to that. Also, with lower co-pay utilization as well, meaning that we launched part of the way through the year in Q2.
Actually what we found is that many of the patients have already reached their co-pay maxes prior to the ARCALYST prescription. Probably less support there around the co-pay than what we actually expected prior to launch as well. Of course, this is, you know, very fluid at the time of launch. I'm sure things will season and normalize as the future quarters go on. I think it's important to say that our Q4 guidance takes into account the early launch experiences and trends that we've seen, so we're confident providing that guidance. In terms of free goods, you know, patient affordability and access is incredibly important to us.
Under Kiniksa OneConnect, our patient services program, we do have different offerings for eligible patients via patient assistance program, bridge for people who may be in between insurers and also a quick start program as well to help patients gain access through while they're waiting for coverage determination for eligible patients. We're very keen on making sure that's available to patients as much as possible. Also it's worthwhile mentioning that the free goods are actually captured under our sales and marketing line in SG&A as opposed to gross-to-net. On the patient disposition part, the long-term extension transition really happened in the first quarter of launch as opposed to Q3.
Really we've seen that and what we announced in the prior earnings release is that around 70% of the U.S. patients on the long-term extension moved across to commercial coverage and commercial drug. That's really already happened. In Q3 and beyond now, this is new patients coming through to have ARCALYST prescribed for the first time. We continue to be very focused on the 14,000 patients, those refractory, the multiple relapsing and the steroid dependency patients. That's a core focus of our field-based team and everything that we do from a digital marketing perspective as well.
We're also cognizant that the broad label that we achieved at the time of approval from the FDA actually allows physicians the flexibility to prescribe where they really think it's gonna help patients the best in recurrent pericarditis. We continue to be focused on those patient groups. I guess it's probably too early to kind of comment on exactly, you know, like how many patients there are within each of the buckets and so on. We're just in the early stages of launch, but very pleased with how it's being received out in the field, both with physicians and also payers and the number of patients.
We're very happy that we now have more than 200 physicians that have prescribed ARCALYST since the time of launch, which is a doubling of Q3 launch numbers.
Got it. Thank you so much.
Thank you. Next we have David Nierengarten of Wedbush. Your line is open.
Hey, thanks for taking the question. I had one, two actually. One on the patient, you know, as the patients are coming in for ARCALYST in recurrent pericarditis, is there any information on kind of mean time since recurrent pericarditis diagnosis? I'm curious if the patients coming in are really long-term patients or are you starting to see some trends towards patients who have been on therapy for a shorter period of time, other therapies for a shorter period of time. My second question is on vixarelimab, just on the recruiting of the phase IIb. Is there any slowdown there? Are you on pace?
You know, kind of how is that study going in the current environment for patient recruitment? Thanks.
Thanks, David. Ross, do you want to take a crack at starting that, and I can always jump in, or me or John can jump in for the vixarelimab?
Yeah, very happy to. Hi, David. Thanks very much for the question. In terms of the time of disease that patients have had when we get prescribed ARCALYST, we really are not providing any metrics on that yet. It's just been at the very early stage of launch. We'll see if that changes as time goes on. I guess the best marker that I can provide right now is maybe two data points. One is the natural history of recurrent pericarditis, where we see that shows a mean duration of recurrent pericarditis of around two years.
When you look at the more kind of severe, if you like, patient population, like what we saw in the RHAPSODY study, the mean duration for those patients had already been 2.4 years, and that was on entry into the trial. Of course, it's, you know, it's highly variable depending on the patient type, and that really, you know, plays into our messaging around the duration of treatment and matching the duration of disease as well, and wanting to make sure patients have adequate duration to support through the underlying auto inflammation that they're ultimately suffering from.
Mm-hmm.
Does that cover your question on?
Yep.
ARCALYST, David? Yeah.
Yeah, it does. Thanks.
Good. Yeah. Maybe I'll start on vixarelimab, and John feel free to jump in. For vixarelimab, obviously, as I said, we've we're well on the way to our dose ranging phase IIb study, which we've said we expect data in the second half of next year. You know, we continue to believe that prurigo nodularis is an area of significant unmet need, and it's obviously a devastating disease and currently no approved therapies. That's obviously the backdrop. The phase IIb study is a 2-year global study driven by, you know, the 16-week time point, which is the primary key efficacy endpoint. You know, all I can say at this point is enrollment is ongoing in the U.S., and we are starting up in Europe and Asia.
We expect to have data in Q2 . You know, we tend to execute very well. I think maybe, John, if you've got any comments on the landscape or anything else on the trial.
No, Sanj, I think you hit the nail on the head there in terms of the trial design. Maybe one last point about, you know, the endpoints. You know, the primary endpoint is a 16-week endpoint, as you mentioned, driven by Worst-Itch NRS. Importantly also, you know, as a secondary efficacy endpoint, is you know, IGA 0/1 attainment or clear or almost clear, you know, from the lesion side, given the data that we saw in the phase II A program, which showed a rapid reductions in Worst-Itch NRS as well as rapid resolution of lesions.
Yep. Got it. Thank you.
Thank you. Next we have Liisa Bayko of Evercore. Your line is open.
Hi. Thanks for taking the question, and great quarter. Two questions from me. The first one, just on rilonacept. Like, how are you thinking about now what the duration of therapy is gonna be? It's just helpful when we think about projecting, you know, beyond 2021. I know there's a comment here that at the 1-year anniversary of the long-term extension, the median duration was 20 months, which is quite long. You now have, you know, prescriptions being written for 12 months. This is certainly beyond the kind of 6-9 months that was the initial kind of, you know, range of thoughts for duration. Is your thinking on duration evolving from 6-9 months?
How would you help us think about that as we think about, you know, 2022 and beyond?
Over to you, Ross.
Yeah. Thank you, Sanj. Hi, Liisa. Thanks very much for the question. Now regarding duration, I guess, you know, we're still at the early stage, so it's difficult to know what the eventual duration is gonna be. I wouldn't say we're necessarily moving away from what we discussed previously, but just acknowledging that there are some unknowns, particularly as we go into Q4 now, when we have a meaningful number of patients who will actually be reaching the 6- to 9-month mark. I think Q4 is gonna be helpful and telling around the potential duration of that time point that you mentioned.
Outside of that, as we said, it's dependent upon the disease, where the patients are in the duration of the course of the disease. You rightly said that we have two insights right now. One of those is the clinical trial insights of the long-term extension, and the point there that we had on one of the slides, you'll remember when we closed out the randomized withdrawal portion of the phase III study, patients had the opportunity to go into the long-term extension portion of the study, and 74 out of 75 of those patients decided to continue on therapy. Remember the randomized withdrawal was a median of 9 months.
The long-term extension is up for an additional 24 months, depending on the physician and patient requirements. Earlier this year, we had a snapshot look at the one-year anniversary of the start of the long-term extension study, and that showed that the median duration at that time point was 20 months in duration. The second insight is really the real world one that we mentioned around two-thirds of the prescribers writing for 12 months, which just gives you maybe a, you know, somewhat of an indication on how physicians are thinking about it and the patients that they're seeing.
Ultimately, it's gonna depend on where they are in the disease course, as well as the willingness for patients to stay on a weekly regimen therapy, as well as the payer approval duration as well. I think there's a lot of uncertainties there. Obviously, kind of hopefully that provides you a little bit of an insight into our thinking on it. I wouldn't say right now that we're moving away from what we've said previously, but time will tell. We're early in the journey.
Now, what just as a follow-up to that, what is it, like, what are you seeing? I don't know if you've done any, you know, kind of market research on this, but the trigger for stopping therapy for physicians.
Yeah. We haven't provided anything on that right now. John, I don't know whether you want to take over on that point and provide any extra context around ceasing treatment through kind of MRI, some of the academic work that's taken place around that, which might help. Outside of that, we haven't shared anything else.
Yeah, no, sure, happy to help out. Liisa, nice to speak with you again. Right. You raise an interesting question, which is, you know, how do physicians monitor patients, you know, understanding, you know, as Ross said, that this is a, you know, it's a long-standing disease, right? The epidemiology points to, you know, several years of duration. You know, you raise an interesting question, which is how does a physician know that when they're, you know, treating a patient chronically and they're doing well, you know, that the underlying, whether or not the underlying autoinflammation has resolved, and it's safe to withdraw therapy.
I think that's really where the the clinical trials data are helpful, because it showed that, you know, continued treatment resulted in continued clinical response, as well as the fact that if the underlying disease is still present, premature cessation of treatment, you know, really unmasks the underlying disease and causes or results in pericarditis recurrence. In terms of some of the markers that that the physician has, they really it's difficult to kind of look at a patient clinically and and reach that conclusion. There are two pieces of information that at least some of the expert cardiologists are using.
The first one is to look at the patient at the time that therapy is initiated, let's say rilonacept therapy is initiated, and you see kind of where they are in their disease course and how long their disease has lasted up until that point, and the severity of the disease in terms of the density of the number of recurrences, as well as some of the associated comorbidities. That's one approach of looking at it at baseline. Another approach is to look at the patient while on therapy, and their imaging technologies, you know, have been shown to be helpful. Again, we've shown data on this point as well, and the Cleveland Clinic has shown data both from the phase II study as well as the phase III study.
What that shows is that there's a phenomenon called delayed hyperenhancement, which is a neovascularization of the pericardium. That shows basically a substrate that can support inflammation. When that delayed hyperenhancement, as it's called, is present, that could be an indicator of the fact that the underlying autoinflammation is still present. What the data have shown is that cessation of therapy was associated with a higher burden of recurrence. Those are the two factors that are, you know, currently available to clinicians to help, you know, define whether to continue with therapy. I hope that's some helpful insights.
Very helpful. Thanks a lot. Just a final question for me on vixarelimab. I know there was some data recently within the last week or so for dupilumab and PN. Maybe you could comment on that and how you see the competitive landscape evolving. As I understand, they also saw resolution of lesions and a pretty nice NRS score. Are you thinking of that as some, you know, kind of temporary benchmark, or how should we think about the dupilumab data in the competitive landscape? Thanks.
Sanj K. Patel, would you like me to jump in on that one?
Yeah, go ahead. Yes.
Okay, sure. We're aware of the data. You know, what we see with the dupilumab data is that they're pretty much consistent with what we've seen with other data from the dupilumab program, for example, in atopic dermatitis. As you know, dupilumab blocks TH2 inflammatory responses. Then what we saw for atopic dermatitis and what we see also in prurigo nodularis is that there's a bit of a lag time that first the inflammation resolves, which then results in reduction of the interleukin-31 levels. Over time, we see a reduction in the pruritus scores. Similarly, you know, over the course of the long-term, you know, trial that they showed, you know, there was a gradual resolution of lesions.
I think that, you know, it certainly is, you know, a helpful data set to see and it's consistent with what we've seen before. We believe vixarelimab is differentiated in this space because vixarelimab is blocking the action of interleukin-31 directly. That's the reason why we saw a much more rapid and more profound reduction in pruritus scores even in the early weeks after initiation of therapy. If you'll remember from our phase II A data, we saw nearly a third of patients had achieved clear or almost clear. That was statistically significant at week 8, but it was also significant at week 6 with early curve separation as early as week 4. I hope that's a helpful comparison of the data understanding it's across trials.
Great. Thank you very much.
Thank you. I see no further questions in the queue. Speakers, I'll return the call back to you for closing comments.
Thanks, operator. Thanks, everybody, for joining in today. Obviously, a great quarter. A lot more to do. We're very excited about both ARCALYST as well as the pipeline, and we're gonna crack on. Thank you. Bye-bye.
That concludes today's conference call. Thank you all for participating. You may now disconnect and have a pleasant day.
Thanks, operator.