Good day, everyone. Thank you for standing by. Please be advised that today's call is being recorded. This call will be conducted in English. This is Kathy Yu, Associate Director of Investor Relations. Welcome to Brii Biosciences' 2024 annual results and corporate update conference call. Our annual results announcement can be found on the investor relations section of our company website. Before we start, I would like to remind everyone that today's call may contain forward-looking statements, which involve several risks and uncertainties. Actual results and outcomes may differ materially from those mentioned in today's discussion. In addition, any forward-looking statements represent our view only as of the day of this call and should not be relied upon as representing our views as of any subsequent date. We specifically disclaim any obligation to update such statements.
Joining us today on the call from Brii Biosciences corporate executive team are Dr. Zhi Hong, Chairman and Chief Executive Officer, Dr. Qing Zhu, Head of China R&D, and Dr. Ankang Li, Chief Strategy and Financial Officer. Dr. Hong will begin with an overview of our strategic priorities and corporate updates. Dr. Zhu will review our clinical programs, followed by Dr. Li, who will review our financial status. We will then open the call for questions. Now over to our CEO, Dr. Hong. Dr. Hong, please go ahead.
Well, thank you, Kathy. Good morning. Good evening. Welcome to our 2024 conference call. We are very pleased to speak with everyone today and to discuss our ongoing progress as we work to address the challenge of hepatitis B viruses. Early in 2024, we made some difficult decisions to prioritize our R&D efforts, terminating or pausing certain programs, reshaping our workforce, consistent with the company priorities. The progress we made in 2024 has strengthened our cash position to support our pursuit of HBV cure as a company's mission in the coming years. Just this past weekend, we presented the most recent finding from our INSURE study at APASL, which we will be discussing today, as well as outlining our next step and goals for the year. I apologize for the delay of this call since our annual report released on March 21st.
This will allow important scientific discussion at APASL, the Asian Pacific Association for the Study of Liver Diseases. The INSURE study provided very important data in understanding the roles of elebsiran and BRII-179 through direct comparisons of cohorts with or without elebsiran, as well as comparisons between BRII-179 responders versus non-responders. We are pleased that the treatment effect size is attributed to the elebsiran and BRII-179 are unequivocal and consistent. This year, our primary focus remains in the infectious disease areas, particularly centered around our HBV program and our three core asset, BRII-179, elebsiran, and tobevibart.
Each has a unique mechanism of action, and we are evaluating this in multiple combination studies with data sets that continue to show the value of our multi-model approaches to address HBV cure, and how a combination or combinations of our asset can produce higher functional cure rates across a broader range of HBV patient groups. In addition, our strategic acquisition of BRII-179 from VBI last December ensures that we can continue developing this unique asset with uninterrupted clinical supply and added commercial upside when we get there eventually. With our resources squarely focused on HBV, as we pursue a functional cure and the right treatment for the right patient subset, we are looking to partner our promising non-HBV program for further development. This includes our HIV long-acting program, BRII-732, BRII-753, and the multi-drug resistant or pan-drug resistance in gram-negative bacteria infection program, BRII-693.
Our HBV functional cure program continues to advance, and with three phase II-B combination studies underway, each asset has a highly differentiated approach with profiles that suggest that we can find optimum combinations that offer higher cure rates for broader HBV patient populations. BRII-179, our optimized recombinant protein vaccine, has shown it can induce strong anti-HBs antigen antibody and broad T-cell responses, suggesting its potential to play a promising role in boosting immune responses against HBV. Particularly, the immune responses induced by BRII-179 shows the potential to profile for patient with stronger intrinsic immunity. To this end, we conduct a proof of concept study on BRII-179's immune profiling potential in cohort four of our INSURE study. The results we share over the weekend reinforce our belief for patient enrichment strategy, especially when the majority of patient may not achieve treatment success or functional cure.
A prospective phase II-B study, known as ENRICH, had been initiated last year and is now fully enrolled. To build on the results from study of elebsiran plus peginterferon alfa combination conducted by Vir and Brii, and the BRII-179 plus peginterferon alfa combination conducted by Brii, that will show convincingly increase the seroclearance of HBs antigen in each combination versus peginterferon alfa alone. We have also initiated the ENHANCE study to look at the potential additive benefit of concurrent treatment of BRII-179, elebsiran, and peginterferon alfa compared to peginterferon alfa alone. The ENHANCE study is fully enrolled.
As we advance each of these trials, we expect to have key interim data readouts throughout the year and well into 2026, that will drive our next step in the clinic as we advance towards registrational studies to achieve the highest HBs functional cure rate for HBs. We understand the competitive landscape, and we continue to focus on achieving the highest functional cure rate that requires sustained immunological control of the HBs infection. Additionally, all three of our assets have been granted breakthrough therapy designation by CDE in China, which continues to represent the world's largest HBs population, our largest target market. In addition to China, our partner, Vir Biotechnology, was recently granted Fast Track and breakthrough therapy designation by the FDA and Orphan Drug and the Prime designation by the EMA for tobevibart and elebsiran.
And this classification shows global regulatory acknowledgement of our assets' potential to offer superior results compared to existing therapies, while also helping expedite their clinical development and regulatory review. Now, I would like to further illustrate our patient enrichment strategy through BRII-179 immune profiling. It is expected that less than 30% of HBV patient will achieve functional cure, despite promising seroclearance rate of HBs antigen of emerging therapies. Therefore, the majority of the patient who will be treated with various agent will not achieve treatment goals of HBV remission. BRII-179 offers a unique opportunity to prime and enrich patients for higher cure rate, enable more patients, hopefully the majority of patients, to achieve their treatment goals. Our latest data show that through such enrichment, we could achieve 56% of seroclearance rate in BRII-179 responders versus only 10% in non-responders, at treatment week 24.
And this is really the midpoint of the 48 weeks of treatment. Interestingly, BRII-179-experienced patients achieved 39% seroclearance as compared, only 16% in BRII-179 naive patient. These are the patient in the cohorts two and three of the INSURE studies at week 24. Suggesting that BRII-179 might have accelerated seroclearances of HBs antigen through priming the immune responses for cure. We believe that patient enrichment is clinically meaningful for physicians and patients to have informed decision or choices for a treatment if the likelihood of achieving a curative outcome is lower. For example, if it's lower than 10%-20%. And treatment failure at such a high rate of 80% to even 90%, may not justify for the healthcare spending and potential tolerability concerns, especially in resource-limiting setting.
So with this overview, I would like to turn the call to Dr. Qing Zhu, who will provide more details on our clinical program. Qing, please go ahead.
Thank you, Zhi. And hello, everyone. Today, I'm pleased to update you on our clinical programs. My discussion will be largely focused on the most recent findings from our INSURE study, which we just presented this past weekend at 2025 APASL. Before we dive into the APASL data, let's recap our ongoing phase II-B clinical studies that Dr. Hong just briefly introduced. Each of the studies is designed to optimize our late-stage development and provide the clear regulatory pathway. The INSURE study has provided key insights into the role of elebsiran, our HBV-targeting siRNA, in advancing towards functional cure on top of peginterferon alfa therapy, with peginterferon alfa as the active control. End of treatment data presented at AASLD last year demonstrated the first clear evidence supporting elebsiran when combined with peginterferon alfa result in a higher risk of HBs antigen loss compared to the peginterferon alfa alone.
In addition, the INSURE study is also evaluating a patient enrichment strategy via BRII-179, and I will review our latest data set from this study arm shortly. Building upon this early evidence, we initiated a second phase II-B study, ENRICH, in a sequential treatment design where patients first receive BRII-179 before proceeding to treatment with elebsiran and peginterferon alfa. This study aims to evaluate BRII-179's ability to profile and select a patient more likely to respond to curative treatment through the HBV specific immune response induced by BRII-179, allowing us to better characterize the immune profile of patients most likely to achieve functional cure. As Dr. Hong discussed, this enrichment strategy is a critical step in refining our patient enrichment approach and how we will design future studies.
Our third phase II-B study, ENHANCE, evaluates the triple combination of BRII-179, elebsiran, and peginterferon alfa compared to peginterferon alfa alone in patients receiving background NUC therapy. We have previously shown that elebsiran plus peginterferon or BRII-179 plus peginterferon can increase HBs antigen loss rate over peginterferon alfa alone. This study is essentially designed to maximize the functional cure rates, assuming additive benefits. Together, these studies are systematically confirming our combination strategy and guiding our decisions on registration pathway. Now I'd like to review some of our recent data from our INSURE study presented at 2025 APASL. I will highlight new data from cohorts one through three, but we're focused on cohort four, which enrolled patients previously exposed to BRII-179 prior to treatment with elebsiran and peginterferon.
Last November, in AASLD liver meeting, we presented 48-week end of treatment data from INSURE study cohorts one through three, which confirmed the superior efficacy of elebsiran and peginterferon combination over peginterferon alfa alone. The study demonstrated that elebsiran in combination with peginterferon achieved a significantly higher risk of HBs antigen loss, 33.3% in the 100 mg group and 26.3% in the 200 mg group, compared to 5.6% with peginterferon alfa alone. This reinforces the role of siRNA as a key component in HBV functional cure strategies. Additionally, we observe that 83% of patients who achieved surface antigen seroclearance also demonstrated anti-HBs seroconversion at the end of treatment, with the majority exhibiting anti-HBs antibody titer exceeding 100 IU per liter. This finding restated the correlation between seroclearance and seroconversion.
With this recap of 48-week end of treatment data from cohorts one through three, I would like to spend a bit more time introducing our preliminary findings in cohort four of INSURE study. The addition of cohort four to the INSURE study was designed as a quick proof of concept to determine whether or not BRII-179 induced HBV-specific antibody responses could guide the treatment decision for higher HBV functional cure rates when followed by a curative combination regime, especially here, elebsiran plus peginterferon alfa. As Dr. Hong mentioned, we believe that this may empower healthcare providers and patients to make an informed decision for treatment. High failure rate is not the ideal outcome of any standard of care.
Our previous studies show that BRII-179 can induce robust HBV-specific antibody and T-cell responses, which correlates with antiviral response in a subset of BRII-179-treated patients, suggesting its potential in boosting immune responses against HBV. In this study, we also observed that a proportion of participants did not mount any detectable anti-HBs response, even after nine doses of Q4W regimen, indicating that anti-HBs antibody response induced by BRII-179 treatment may have the potential to identify patients with intrinsic immunity more likely to respond to subsequent curative treatment. To this end, we conducted a proof of concept study evaluating BRII-179's immune profiling potential in cohort four of our INSURE study by calling back patients from the previous study of BRII-179 in combination with elebsiran.
This approach allows us to quickly assess whether patients with BRII-179-induced immune response would have higher response rates to elebsiran and the peginterferon alfa combination therapy than those without. A total of 31 patients were voluntarily enrolled in the cohort four who were NUC suppressed and received BRII-179 and elebsiran combination treatment in the previous BRII-179 A3501 study. All had completed previous 179 and elebsiran treatment for more than one year. 28 participants with baseline surface antigen 100 - 300 IU per ml at the time of participating in the INSURE study were included in the efficacy analysis presented here. These participants were grouped based on their anti-HBs antibody response induced by prior BRII-179 treatment.
Those with peak anti-HBs titers equal or greater 10 IU per liter are defined as BRII-179 responders, and those with peak anti-HBs titers less than 10 IU per liter as BRII-179 non-responders. Although retrospectively grouped based on BRII-179-induced antibody response, demographics and baseline characteristics were comparable between responders versus non-responders or BRII-179-naive participants in cohorts two or three. Notably, the BRII-179 responders and the BRII-179-naive groups had slightly higher baseline surface antigen level than the BRII-179 non-responders. At the APASL 2025, we presented a 24-week on-treatment data from cohort four. What we found in cohort four was that BRII-179-induced anti-HBs responders achieved substantially faster and deeper surface antigen reduction, relative to baseline than non-responders or BRII-179-naive participants through the week 24.
In the chart on the left hand, we see at week 24, the BRII-179 responder group achieved more than three logs 10 IU per milliliter mean HBs antigen change from the baseline, where the BRII-179 non-responders group only achieved 1.7 log 10 IU per milliliter. As shown in the figure on the right hand, the BRII-179 responders achieved 56% surface antigen loss rate after 24 weeks of treatment, notably higher than non-responders' 10% surface antigen loss rate and BRII-179 treatment-naive participants at the 16% loss rate. This encouraging preliminary data suggests that patient enrichment through profiling antibody response induced by BRII-179 has the potential to significantly increase the HBV surface antigen loss and achieve the higher functional cure rate in a subset of patients. Based on the 24-week treatment data from cohort four, we envisioned a potential chronic HBV treatment paradigm.
Through the immune induction and profiling by the BRII-179, we can potentially identify the right patient, those most likely to respond to curative treatment. BRII-179 has demonstrated the potential to play a pivotal role here. Our strategy focuses on enriching HBV patient populations through immune activation while minimizing unnecessary treatment for those less likely to respond. Our confirmatory phase II-B ENRICH study aims to validate this approach by looking at the impact of a sequential combination treatment of BRII-179 followed by elebsiran and peginterferon alfa to prospectively confirm that BRII-179 can indeed prime the immune system and enrich patients for higher likelihood of functional cure. Looking beyond the ENRICH study, our enrichment strategy is designed to be generally applicable because it relies on patients' intrinsic immune responses, which are important for persistent control of HBV infection or long-term remission.
BRII-179's role as immune primer and immune profiler may not be limited to just HBV patient enrichment. It could also be a critical component of future chronic HBV treatment regimes. By taking a stepwise approach, we can exemplify the patient enrichment strategy in the first phase and apply these insights to broader combination regimes in the second phase, ensuring we're maximizing functional cure rates across different treatment strategies. This multi-trial approach allows us to systemically validate patient enrichment as a strategy to optimize functional cure outcomes. By integrating BRII-179 with other curative therapies, we are not just developing a treatment. There is a potential to change the HBV treatment paradigm and empower physicians and patients to make informed treatment decisions.
To summarize, there is already a consensus in the industry that immunotherapeutics are a critical component in achieving sustained HBV functional cure, as immune restoration or activation is associated with effective and durable control of HBV infection. Identifying the right patient, those most likely to respond to treatment, may lead to improved curative outcomes and reduce the treatment failure or HBs antigen rebound. BRII-179 has the potential to be the key patient enrichment tool in a broad patient population, as we have shown that it can profile a patient's HBV-specific immune responses and enrich immune responsive individuals. By integrating BRII-179 into our clinical framework, we aim to create a more targeted treatment approach, increasing the probability of functional cure while reducing unnecessary therapeutic interventions. This is particularly relevant in resource-limited settings as we explore novel combination regimes that are expensive and have potential tolerability or safety concerns.
The ability to stratify patients based on their immune responses to BRII-179 could allow us to optimize treatment pathways, ultimately enhancing clinical outcomes for patients with HBV. As we advance our HBV clinical program, upcoming data readouts this year will play a defining role in shaping our late-stage clinical development and regulatory approach. Our timeline for 2025 includes several key milestones across multiple studies. The INSURE study cohort four 24-weeks interim analysis is what we just reviewed with you today. Throughout the year, we will continue to share with you our 48-week end of treatment data and 24-week follow-up data when they become available. Additionally, our development partner, Vir Biotechnology, is advancing their ECLIPSE phase III registrational program in chronic hepatitis B with elebsiran and tobevibart. The first patient was already enrolled in March 2025.
For HBV, Vir's 24-week follow-up data from the MARCH study evaluating elebsiran and tobevibart with or without PEG-IFNα are expected in Q2 this year. This data point will provide necessary evidence to refine our clinical approach, optimize our regulatory pathway, and bring us closer to delivering a scalable and curative solution for HBV. As we focus on advancing our HBV program, we will continue to seek external partnerships to develop our non-HBV programs. In MDR/XDR gram-negative bacterial infections, we have BRII-693, the next generation polymyxin that recently gained IND approval from CDE for clinical evaluation in China. In HIV, we have two core assets focusing on long-acting delivery of EFdA, BRII-753, a long-acting injectable, and BRII-732, a once-a-week long-acting oral regime. With this, I will now pass the call to Dr. Ankang Li, Chief Strategy and Financial Officer. Ankang.
Thank you, Qing. Thank you everyone for joining tonight's call. As a reminder, the financial figures I will review today are in Chinese RMB. We ended 2024 with a strong cash position. As of December 31st, 2024, our cash and cash equivalents, bank deposits, and restricted bank balance were CNY 2,413.4 million, representing a decrease of CNY 248 million or 9.3% compared with CNY 2,661.4 million at the end of 2023. The decrease was primarily due to the payout of daily operations and research and development activities. We expect our current funds to be sufficient to support our operation beyond 2028. Our other income was CNY 141.4 million in 2024, representing a decrease of CNY 22.3 million or 13.6%, compared with CNY 163.7 million in 2023.
This was mainly due to bank interest income of CNY 20.8 million, which is attributable to the decrease in interest rate on USD and Hong Kong dollar time deposits of about $20 million, and also the decrease in income recognized from government grants. We continued to align our spending with our core strategic priorities and optimizing our organization to effectively control our operational costs. As a result, we reduced our research and development expenses for the year 2024 by 38% to CNY 249.8 million from our CNY 402.7 million in 2023. The reduction included a decrease of CNY 79.3 million in third-party contract costs and CNY 67.7 million in employee costs. Administrative expenses were CNY 152.3 million in 2024, declining by 22% compared with CNY 196.5 million for 2023. The decrease was primarily attributable to decreased employee costs of CNY 39.7 million, which was primarily attributable to pipeline prioritization and organizational optimization.
With a healthy financial position, we are confident to support our HBV programs in late-stage development and seek partnership opportunities for our other promising assets. We are committed to drive long-term value for our shareholders as we progress pioneering therapies aimed at expanding treatment options and accessibility for patients. This concludes our prepared remarks. We will now open the call to your questions. Kathy, please.
Okay. Thank you, Ankang. We will now open the line to Q&A. If you have questions, please click Raise Hand in the webinar controls, and we will prompt you to unmute yourself. Please the Moderator to unmute Roanna from Leerink Partners.
Hey, everyone. Can you hear me okay?
Yes.
Okay, great. A couple of questions from me. First one is, what do you hope to see from the ongoing phase II-B HBV trial readouts that are coming up in terms of functional cure rates based on what you learned from APASL? Depending on the level of efficacy, what would your next steps be for these programs? Would you pick one to go forward in phase III, or what are the different paths there?
Roanna, just trying to clarify, you talk about our phase II study, or you talk about the entire industry's phase II study in terms of APASL?
Your ongoing phase IIs specifically.
Okay. Yeah. I think we presented two oral presentation at APASL meeting, really looking at the INSURE study, where we have the end of treatment and the follow-up data in terms of antibody response for the cohort one to three. That is a direct comparison of elebsiran plus peginterferon alfa compared to PEG-IFNα alone. That data we presented at the APASL meeting, and the one that Qing Zhu just described was the cohort four, which is the first time we presented, where we really compare two things. One is the BRII-179 responders versus non-responders, and try to support our value proposition, that is, once BRII-179 has the ability to identify patient for cure. Then another comparison, although it is not a direct comparison, but it is a comparison in the same study where you look at BRII-179 naive versus BRII-179 experienced patient.
In this case, we only had 24-week data. We show at week 24, we have almost 40% of surface antigen loss for the BRII-179 experienced patient versus the cohort two and three that have never seen BRII-179 before. I think that is important. If you look our study of the INSURE study as well as the Vir study that they conducted before, about half of the patient actually lose their surface antigen in the second 24 weeks of the siRNA plus PEG-IFNα. The data is very consistent for the BRII-179 naive patient. What is really interesting is that now the one that who have been previously treated BRII-179, and because their immune system have been primed, and they have achieved a much higher and accelerated loss of surface antigen.
Obviously, we need to follow this patient for the additional 24 week of treatment and also the 24 weeks of follow-up. There are data to be further mature in the coming year. With regard the phase III study, whether or not we're going to do one or two, this is something that we need to consider. The competitive landscape is actually evolving, and, Roanna, as you know, there are some data that are coming from the antisense, and that phase III study has completed, and they're in the follow-up period. There's also other similar ASO compounds that are also producing pretty impressive end-of-treatment surface antigen loss.
We believe the competitive landscape is begging for a higher functional cure rate. With that in mind, in the past, we have always presented that we believe through the various combination, we can achieve anywhere between 30%-60% of functional cure rate. We have talked about this in the past.
I think now we really need to aim a little higher, that is more close to the upper limit of our projection in the past, and close to 60% rather than close to the 30%. I know this is something that is quite exciting, and if you talk about this maybe two years ago, people probably would think that you're in a different planet. I think this cohort four data is giving us confidence that we could potentially achieve that high level of functional cure in patients that have a sufficient or strong intrinsic immunity that are more susceptible to curative treatment. I think with that in mind, we think there's a strong component in the patient enrichment strategy, because we believe that's going to help us to push the cure rate to the upper range of our forecast in the past.
Whatever the phase III study we're going to design, we're still in the process of deciding, is it going to have that patient enrichment strategy? Now obviously, the ENHANCE study hasn't been completed yet, so we're looking at that as well. If that concurrent treatment also give us very good information, I think then there are very interesting options for us to really think about how to do this. Our goal has shift, Roanna. Now, we're not satisfied with 30% anymore. We're thinking about more on the higher end of the range.
Got it. That's interesting. A quick follow-up from me. I was curious, what do you think about the pros and cons of including peginterferon alfa in an HBV combo regimen in the future? Would you consider trying to remove it if you can prime patients with BRII-179?
Interesting. That is something we are looking at. The recent data was shown at 24 weeks. It looks very exciting, right? It looks like everything is going pretty fast. Now it open up the opportunity, can we shorten the peginterferon alfa treatment to 24 weeks instead of 48 weeks? That is something we need to understand in terms of how, as we follow these patients through, and to think about how to optimize the final curative treatment. As you know that there are other study, multiple study, have shown that PEG-IFNα play a role in sustain the loss of surface antigen. But exactly how that work is not entirely clear. I think this is something that we need to watch. And obviously our ultimate goal is to spare interferon, the use of interferon. But if we cannot achieve that, at least we should aim to shorten that.
And this is a part of the consideration for phase III study design again. Obviously, if we want to do a phase III study, Roanna, I can do the study today. I can initiate a phase III study today. But the point is in making sure that you have a competitive regimen as we go forward. The competitive landscape, very excitingly, is moving to higher bars. I think we need to think about that very carefully at this point, not to be kind of too overreactive in terms of starting phase III and then to trying to impress investors who probably not looking at the data as closely as we are. Our goal is to start phase III as soon as we can, but achieve the higher range of the functional cure rate we have forecast in the past.
Yep, makes sense. Thanks again.
Yep. Thank you.
Okay, thank you, Roanna. Now we are looking for another questions. Audience, if you have questions, please click Raise Hand in the webinar controls, and we will prompt you to unmute yourself. Before we are waiting for another questions, I have some offline questions. There is a question asked that we can see the data from cohort four shows the median baseline for BRII-179 responders and non-responders are roughly 500 and 200 respectively. Based on that, how should we project the surface antigen baseline characteristic for ENRICH trial? What is the median baseline for the enrolled patients, and can it reflect the real-world surface antigen level distribution?
Okay, good question. I think our ENRICH study inclusion criteria is with the baseline surface antigen from 100 to 3,000, and that is the enrollment criteria. We actually control the strata of this range, meaning that we are not just randomly enrolling patients with lower baseline surface antigen. We actually ensure there is sufficient representation of patients in the higher range of the baseline, that is, i.e., from 1,500 - 3,000 IU per milliliter. So that is something that we are considering for the ENRICH. I think the study that we have shown in the cohort four, and clearly we see a slightly higher surface antigen level in the responders versus non-responder. The baseline surface antigen is similar to the naive patient, which also in the INSURE study had an inclusion criteria from 100 -3 ,000.
I think it is interesting to also look at some of the baseline information in the previous BRII-179 elebsiran studies. We have seen that really the BRII-179 can induce immune response regardless of the baseline surface antigen level. Also, it seems to be regardless of the e antigen positivities, which is actually very interesting. This is providing another patient enrichment tools, not limited to just the low baseline surface antigen. It may allow us to use BRII-179 to enrich patients in a much broader patient population and with regard to the baseline surface antigen as well as e antigen status. As you know, some of the study that has been done so far, many of them focus on low baseline surface antigen and also e antigen negative. For us, the BRII-179 offers the chance to broaden that baseline as well as the e antigen status.
Okay, thanks, Zhi. I have another question that, given the priming capability of BRII-179, does the company considering any BD opportunities for BRII-179 to compare with other modalities?
Yes. That's an interesting question because we think the BRII-179 ability to enrich patient is not just limited to elebsiran plus peginterferon alfa. I think it's generally applicable because we're really talking about patients' intrinsic immunity, which I don't think that's modality-dependent in that regard. We do believe BRII-179 had ability to combine with other curative regimens, such as antisense or other curative regimens. Clearly this is one area that as our data mature, as we see more and more follow-up data from elebsiran, we'll be able to understand what those opportunities are. Just so that for everybody to be aware of, the elebsiran phase III study is fully enrolled, and it's actually, the treatment has split, so they're in the follow-up period. We're very eager to see what's their final cure rate as they are completing or concluding their phase III studies.
From the previous study we have shared and multiple studies from elebsiran, we're seeing HBV surface antigen rebound from anywhere from 50% - 70%. We believe that, even though the antisense has a very strong ability to induce surface antigen serum clearances, I think rebound continue to be an issue with antisense. I believe because the similarity of the other antisense with the elebsiran, we believe the same thing would be true. So there's more things that we can look at this, and obviously when the data fully mature, I think the business opportunity may become together.
Thank you, Zhi. Looks like there's no other questions now. So this concludes the Q&A portion of today's call. Now I will turn the call to Dr. Hong for the final remarks. Please, Zhi.
Well, thank you, everybody, for joining. We have conducted a conference call early today or evening in U.S. There are a lot of questions and enthusiasm from investors, and we appreciate that. There's a lot of questions having asked and new questions being asked. In summary, we have a hugely strong data that support the ongoing development of our advanced HBV cure program. Our findings increasingly illuminate our clinical and regulatory pathways. The data sets this year and next will tell us more, and there's more to come. With BRII-179, we're seeing the potential for application in priming the immune system and to accelerate the loss of the serum clearance of surface antigen and also helping identify patients most likely to benefit from curative treatment, while elebsiran and tobevibart continue to show promise as component of combination treatment regimens.
Findings from our ongoing phase II-B INSURE/ENRICH ENHANCE study will inform our registration and regulatory strategies guiding a more precise approach for HBV functional cure. As I mentioned earlier, we are looking at a higher functional cure rate and what we have discussed and communicated with you in the past. We think that is a good thing for patients. I want to thank you for your ongoing support. I look forward to your continued support speaking with you and providing more information as our data continue to mature later this year and next. Thank you, everybody, for joining the call, and have a good day.
Thank you all again for joining us today. Please feel free to reach out to us via ir@briibio.com in the meantime with any further questions. Thank you. Goodbye.