Thank you. I would now like to turn the conference over to Jeff McDonald, Executive Director, Investor Relations. Please go ahead, sir.
Thank you, Operator, and good afternoon, everyone. We are excited to have the opportunity today to review the compelling clinical data that supported the approval of Ziihera in second-line biliary tract cancers. We'll also discuss our commercial launch plans in second-line BTC, along with continuing clinical development plans for zanidatamab. The slide presentation accompanying this webcast is available on the Investors section of our website. On the call today from Jazz are Renée Galá, President and Chief Operating Officer. Dr. Rob Iannone, Executive Vice President, Global Head of Research and Development and Chief Medical Officer. And Abizar Gaslightwala, Senior Vice President, Head of U.S. Oncology. We are also incredibly pleased that Dr. Shubham Pant, Professor in the Department of Gastrointestinal Medical Oncology and the Department of Investigational Cancer Therapeutics at the University of Texas MD Anderson Cancer Center, is participating in today's call.
On slide two, I'd like to remind you that today's webcast includes forward-looking statements which involve risks and uncertainties that could cause actual events, performance, and results to differ materially. We encourage you to review the statements contained in our slide deck and the risks and uncertainties described in our SEC filings, which identify certain factors that may cause the company's actual events, performance, and results to differ materially from those contained in the forward-looking statements made on today's webcast. We undertake no duty or obligation to update those forward-looking statements. Now I'll turn the call over to Renée.
Thanks, Jeff, and welcome to those of you joining us today. I'll begin on slide four. We are exceptionally pleased that FDA approved zanidatamab under an accelerated approval on November the 20th for the treatment of adults with previously treated unresectable or metastatic HER2-positive biliary tract cancer. Zanidatamab, marketed under the name Ziihera, is the first and only dual HER2-targeted bispecific antibody approved for HER2-positive BTC in the U.S. BTC patients have a very poor prognosis, and existing treatments have offered limited clinical benefit. We are excited to bring this much-needed therapy to patients with BTC and to announce that Ziihera is now available to prescribers in the U.S. This is the first of multiple indications where we believe zanidatamab could make a meaningful impact in the lives of patients living with HER2-positive cancers.
Slide five provides our agenda for today's call, which will start with an overview of the clinical data from HERIZON- BTC-01. We have the privilege of being joined by leading BTC expert, Dr. Shubham Pant, who will walk us through the current clinical practice for treating BTC and highlight the exciting data from the HERIZON- BTC-01 trial, which he recently presented at ASCO 2024. Rob Iannone, our Global Head of Research and Development, will review the Ziihera label and outline our zanidatamab development program, which is evaluating zanidatamab across multiple tumor types and lines of therapy. Our Head of U.S. Commercial Oncology, Abizar Gaslightwala, will discuss our commercial strategy for Ziihera. While the BTC indication is a rare cancer, we believe it is the first of many indications where Ziihera can make a meaningful impact in the lives of patients living with HER2-positive cancers.
Moving to slide six, I'm incredibly proud of the work our entire organization has done to advance the development of Ziihera through this first approval. Ziihera is the only therapy approved specifically for HER2-positive BTC, providing a much-needed therapeutic option for this difficult-to-treat cancer. We also believe Ziihera will be an important part of our growing oncology portfolio for the foreseeable future, representing a potential $2 billion global opportunity across multiple HER2-positive indications. The launch of Ziihera highlights our growing capabilities in the oncology space. Ziihera is our third oncology product launch since 2020, following the successful development and commercialization of Zepzelca and Rylaze, and in particular, we are excited to leverage our considerable experience in solid tumors with Zepzelca. Our oncology team's strong background in both solid tumor and the HER2-positive space will be important as we look to advance into other indications.
Turning to slide eight, it is my pleasure to introduce Dr. Shubham Pant, Professor in the Department of Gastrointestinal Medical Oncology and the Department of Investigational Cancer Therapeutics at the University of Texas MD Anderson Cancer Center. Dr. Pant is a leader in the field of GI cancers, including extensive experience in treating patients with BTC, as well as serving as an investigator in multiple clinical trials. He serves as the Director of Clinical Research and Associate Director for Early Phase Drug Development at the Sheikh Ahmed Bin Zayed Center at MD Anderson and on the ASCO GI Guidelines Committee. Dr. Pant was an investigator for the zanidatamab HERIZON- BTC-01 trial and presented data from the trial at an ASCO oral session that received the Best of ASCO Award in 2023.
He is also senior author of the Lancet Oncology manuscript on the phase IIb data from the HERIZON- BTC-01 trial. Dr. Pant?
Thank you, Renée. Hi, this is Shubham Pant, and Renée has graciously given you my introduction. So starting with slide nine, as you can see, there is significant unmet need which remains for our patients with biliary tract cancers. When you really look at second-line therapy after first-line chemotherapy, which is normally with gemcitabine, cisplatin, and a checkpoint inhibitor, the second-line therapy offers about a 5% response rate. HER2-targeted therapies have exhibited clinical benefit in other indications. However, currently, there are no approved HER2-targeted therapies specifically for BTC. We did have a recent approval of trastuzumab deruxtecan for HER2 overexpressing pan-tumors in patients without any treatment options, in which HER2 3+ for BTC was included. Next, on slide 10, I'm going to briefly speak to zanidatamab mechanism of action, Rob will later detail in the presentation. It's a bispecific antibody.
It essentially binds to two separate HER2 molecules in trans, so where trastuzumab and pertuzumab bind, it's called extracellular domain II and IV, and it's got a unique mechanism of action in which it induces immune-mediated effects like ADCC, and interestingly, it also facilitates internalization and degradation of HER2, so you kind of lose the target on the surface of the cancer cells, and it also prevents HER2 dimerization and intracellular signaling. Now, on slide 11, I'm going to present the HERIZON- BTC-01 trial, so this trial was a global single-armed phase IIb trial of zanidatamab monotherapy in patients with locally advanced or metastatic HER2-amplified BTC, and these patients had to have progressed after treatment with a gemcitabine-containing regimen, so very similar to what we do in clinical practice. This was first presented in ASCO 2023, as Renée noted, and we updated this at a presentation in ASCO 2024.
The key eligibility criteria were that the patients had to be greater than or equal to 18 years of age. You had to have confirmed locally advanced or metastatic HER2-amplified gallbladder cancer, intrahepatic cholangiocarcinoma, or extrahepatic cholangiocarcinoma. Those are different types of biliary tract cancers. Again, patients had received greater than or equal to one previous gemcitabine-containing systemic chemotherapy regimen. ECOG was 0-1, and patients did not have any prior HER2-targeted therapies. Coming to slide 12, we had two cohorts in this. There was cohort one, which was HER2-positive, which was IHC2+ or 3+, and there was cohort two, which was IHC0 or 1+. We reported out the results of IHC2+ or 3+, and all these patients were ISH positive. That means in situ hybridization positive.
Zanidatamab was given IV single agent days one and 15, and every eight weeks, we did a restaging scan, and our primary endpoint was confirmed overall response rate, but selected secondary endpoints of duration of response, disease-free survival, progression-free survival. Coming to slide 13, these are demographic and baseline characteristics. Patients majority had ECOG 0 or 1. As you can see, there were different disease subtypes of gallbladder, intrahepatic, or extrahepatic cholangiocarcinoma. Important to note, the majority of the patients were IHC3+, which was 78%, and the majority of patients had stage IV disease, about close to 90%. Coming to slide 14, when you looked at the disease response, and again, this was confirmed overall response rate, was 41.3% in patients, and the disease control rate, that's response plus stable disease, was 68.8%.
Two patients achieved a complete response, and interestingly, the median duration of response, that means in the responding patients, how long was the median duration that they could stay on, was 14.9 months. Now, again, the trial was not designed to detect treatment effects by HER2 status. The confirmed overall response rate of IHC3+ tumors, so it's important to make the distinction, IHC3+, which was the majority of the patients, the confirmed overall response rate was 51.6%, and in IHC2+ patients, it was 5.6%. Coming to slide 15, this is called the waterfall plot. Again, anything under the line kind of going down, that means they had a decrease in measured tumor lesions. So 68% of patients had a decrease in measured tumor lesions.
And if you can see the different shadings of blue, the patients with gallbladder cancer, intrahepatic cholangiocarcinoma, or extrahepatic cholangiocarcinoma, all of these subtypes did seem to get some benefit from the therapy. Coming to slide 16, and this is the duration of response that we talked about. The median of duration of response when we presented it in ASCO 2023 was 12.9 months. On longer follow-up, it increased to 14.9 months. The median duration of response, again, of IHC3+ patients where the response rate was 51.6% was 14.9 months. The median progression-free survival was 5.5 months. And in patients with IHC3+ tumors, the median progression-free survival was 7.2 months. With the IHC2+ patients, the median progression-free survival was 1.7 months. Coming to slide 17, when you look at overall survival, the median overall survival, again, these patients were pretreated patients. They had received a gemcitabine-containing regimen before.
The median overall survival was 15.5 months. Coming to slide 18, this is overall safety of zanidatamab. Somebody who was given zanidatamab in the clinical trial, this was a well-tolerated drug. The side effects were manageable. The majority of treatment-related adverse events were low-grade. One of the side effects we saw was diarrhea, which was easily reversible with antidiarrheal medications. There were no deaths related to zanidatamab treatment. One patient experienced serious treatment-related adverse events since their primary analysis, and the dose reductions were infrequent, and you can see out here in the table that you have the treatment-related adverse events. As you can see, the majority were grade I and grade II. Coming to my conclusions on slide 19. In this long-term analysis, zanidatamab monotherapy demonstrated durable and sustained anti-tumor activity in patients with previously treated HER2-positive, unresectable, locally advanced metastatic BTC.
Overall response rate, this is for both IHC2+ and 3+, was 41.3% with a median duration response of 14.9 months. The median overall survival in this pretreated patient population was 15.5 months. It was actually more, which was 18.1 months in patients with IHC3+ tumors. Safety profile of zanidatamab monotherapy was manageable with favorable tolerability. Serious or high-grade TRAEs, treatment-related adverse events, were infrequent. No treatment-related deaths. The efficacy, again, this efficacy and the response rate, especially duration of response, is notable in these patients who normally have a poor prognosis. Like I showed you, which was non-target therapy, they have a response rate of 5%. And again, these were used for filing with the FDA. So I just want to come to slide 20 and acknowledge our patients and co-investigators who contributed to the trial. We appreciate their input.
Now I'm going to give it over to Rob to go forward with the clinical and development overview. Rob?
Thank you, Dr. Pant. That was an excellent overview of the current BTC patient experience and data underlying the recent approval of Ziihera. My name's Rob Iannone. I'm head of research and development and CMO at Jazz, and I want to begin by highlighting why we are so excited about zanidatamab's potential across HER2-positive cancers. Clinical data to date using zanidatamab as monotherapy has shown promising activity across a range of tumor types, along with demonstrating positive clinical results in combination with chemotherapy and targeted therapies in patients previously treated with other HER2 agents, and importantly, has resulted in durable responses with both encouraging PFS and overall survival. On slide 22, we've highlighted zanidatamab's unique mechanism of action and clinical activity. Zanidatamab is a HER2-targeted agent that has demonstrated activity in multiple HER2-expressing cancers.
It has multiple mechanisms of action, a bispecific monoclonal antibody with biparatopic binding. Zanidatamab simultaneously binds to extracellular domains II and IV, which correspond to the Herceptin and Perjeta binding domains. However, zanidatamab's unique mechanism of action has shown greater efficacy relative to the combination of Herceptin and Perjeta preclinically and has shown strong clinical activity in patients whose cancer has progressed after Herceptin and Perjeta. Zanidatamab binds in a biparatopic fashion, such that each antibody typically binds to two receptors. This results in multiple mechanisms of action, all causing tumor cell death. As seen on the left side of the figure, zanidatamab interferes with HER2 signaling and also disrupts heterodimerization of HER2 and HER3, further inhibiting tumor cell signaling and growth.
Zanidatamab causes receptor clustering and receptor internalization, as shown in the middle part of the slide, and induces immune destruction through ADCC, ADCP, and CDC, as shown on the right and bottom. We think zanidatamab induces CDC at a level that is highly differentiated in the category. Slide 23 highlights significant and unique clustering of HER2 receptors on the surface of the cell exposed to zanidatamab, which drives enhanced internalization and downregulation of HER2 proteins, as well as activation of complement-dependent cytotoxicity, resulting in tumor cell death. Next, on slide 24, zanidatamab is shown to activate the complement pathway, eliciting complement-dependent cytotoxicity, which is believed to contribute to the clinical efficacy. Slide 25 shows our label.
As you may have seen in our November 20th press release, Ziihera is indicated for the treatment of adults with previously treated unresectable or metastatic HER2-positive, defined as IHC3+ biliary tract cancer, as detected by an FDA-approved test, and was granted accelerated approval based on overall response rate and duration of response. In addition to having an approved label, zanidatamab is also now listed in NCCN Guidelines and Treatment Compendia. As the label notes, continued approval may be contingent upon verification of clinical benefit in a confirmatory trial. And as we previously announced, we have a confirmatory trial ongoing in first-line biliary tract cancer. Ziihera is administered as an IV infusion with weight-based dosing at 20 milligrams per kilogram once every two weeks. Premedication with acetaminophen, antihistamines, and corticosteroid prior to administration of Ziihera has been shown to help prevent potential infusion-related reactions.
It is important to highlight the warnings and precautions from Ziihera administration, which include left ventricular dysfunction, infusion-related reactions, and diarrhea. The most common AEs, those greater than 20%, are diarrhea, infusion-related reactions, abdominal pain, and fatigue. Additionally, Ziihera has a boxed warning for embryo-fetal toxicity. Moving to slide 26, I want to start by highlighting that while this is a cross-study comparison and patient characteristics may differ between the two studies, this slide shows observed clinical activity for commonly used treatments for patients with advanced biliary tract cancer. The standard of care for BTC patients in the U.S. is the chemotherapy regimen FOLFOX, which includes folinic acid, fluorouracil, and oxaliplatin. Recent guidelines from NCCN and ESMO recommend FOLFOX plus active symptom control for second-line BTC treatment.
The other commonly used regimen is the combination of trastuzumab and pertuzumab, with data here shown in HER2-positive BTC patients from the MyPathway study. Moving to slide 27, we've included a table that shows some key outcomes from data sets that have been presented on our HERIZON- BTC-01 trial, as well as the DESTINY-PanTumor02 trial within HER2. DESTINY-PanTumor02 was the basis for an accelerated approval in the U.S. for the treatment of HER2-positive solid tumors in patients who have received prior systemic treatment without satisfactory treatment options. I'll note that in this cross-study comparison, the table includes data from IHC3+ patients only from both trials. Given the differences between these patient characteristics of the respective populations, information here should not be used to make direct head-to-head comparisons.
In the HERIZON- BTC-01 trial, zanidatamab demonstrated promising results with a 51.6% confirmed ORR and a median duration of response of 14.9 months in cohort one patients who are HER2-positive with IHC3+ expression. As is typical for single-arm data when presented in a product label for an oncology therapy receiving accelerated approval, PFS and OS are not included in the Ziihera label. However, we have included these data here for HER2-positive IHC3+ patients, as shown on the slide. The compelling data for zanidatamab in HER2-positive BTC highlighted here is resonating with oncologists, and most importantly, with the underserved patient populations who have a high unmet need and currently lack any specifically approved HER2-targeted treatment options. I will now turn the call over to Abizar Gaslightwala, head of our U.S. Oncology Business Unit, to discuss our commercial launch strategy for Ziihera. Abizar?
Thanks, Rob. Starting on slide 29, BTC is a heterogeneous group of aggressive malignancies in the biliary tract classified according to cancer origin. BTC includes intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder cancer. Approximately 3,000 first-line and second-line patients are diagnosed with HER2-expressing BTC in the U.S. each year. BTC is particularly aggressive with a global five-year survival rate of less than 5%. Most patients are diagnosed with advanced or metastatic disease, which has a very poor prognosis. With metastatic second-line BTC, the median overall survival is approximately six months with current standard of care used most widely today, and only up to 12 months with recently approved T-DXd therapy in IHC3+ specific patients. Clearly, these current treatments are not adequately addressing the needs for this population.
Ziihera represents a meaningful advance for HER2-positive patients who need additional treatment options, and we are excited to bring this new therapy to transform treatment outcomes for patients with this devastating disease. As Dr. Pant spoke to early in the presentation, BTC patients are in need of more effective treatment options. Patients often don't respond well to chemotherapy or can't tolerate treatment with chemotherapy, and first-generation HER2-directed therapies are not approved for use in this population. Patients and physicians are looking for better treatment options for the second-line HER2-positive setting that can deliver greater efficacy outcomes, are well tolerated, and can be taken for extended periods to maximize patient outcomes and benefit. With our recent approval, Ziihera has the potential to address this opportunity with its key product attributes across efficacy, safety, and tolerability.
Now on slide 30, the compelling data and durable responses for Ziihera are already resonating with oncologists, healthcare providers, and institutions. We believe this will translate into a strong willingness to adopt Ziihera for HER2-positive second-line BTC patients and differentiate Ziihera from existing therapies used currently today. In addition, oncologists are recognizing the other key benefits of Ziihera's profile, including its uniqueness as a dual-target HER2 bispecific antibody that delivers differentiated efficacy results and established safety and tolerability profile, ease of administration, and single-agent activity without chemotherapy. Moving to slide 31, as discussed earlier by Dr. Pant and Rob, Ziihera's unique mechanisms of action differentiate from other HER2-targeted treatment options. As shown on this slide, we believe Ziihera's compelling clinical profile will enable it to become the therapy of choice in HER2-positive second-line BTC patients.
Our goal is to become the market leader and treatment of choice for these currently underserved patients, most of which are in the community setting and are treated in their local healthcare systems. In addition, we believe this initial launch in second-line HER2-positive BTC will help establish Ziihera as a best-in-class HER2-targeted therapy for multiple HER2-positive solid tumors moving forward, which Rob will outline later in more detail. On the right-hand of this slide, we include a photo of one of the patients in our clinical trial. This is what drives us to Jazz. We're grateful to all the individuals who participated in the trial, paving the way for us to bring this therapy to second-line HER2-positive BTC patients who can potentially benefit from Ziihera now that we have approval.
Turning to slide 32 in our launch strategy, we have the right team and the right capabilities in place to deliver a successful launch of Ziihera in second-line HER2-positive BTC. Our established oncology field teams across sales, medical, and access have strong relationships with the solid tumor oncology customer set, leveraging our presence there already. Further, the physicians currently diagnosing and treating BTC patients significantly overlap with our existing oncology call universe, positioning us to leverage our current footprint to help accelerate the launch and uptake of Ziihera for second-line HER2-positive BTC patients. In our scientific exchange interactions with these customers and institutions, they have conveyed the need for better therapies developed specifically for this very critical HER2-positive BTC population, and they are excited about the promise of Ziihera. Key launch activities are already underway, and Ziihera is now available to prescribers.
The wholesale acquisition cost, or WAC, of Ziihera is $7,110 for a two-pack of two 300 milligram vials. Based on the median assumed weight for a BTC patient in the United States, the 28-day cycle for WAC cost is approximately $35,500. Ziihera is the only FDA-approved chemotherapy-free regimen for patients with HER2-positive BTC, and there are no other HER2-targeted agents approved in first-line or second-line specifically for BTC. The price of Ziihera represents the value this new therapy brings to the HER2-targeted cancer treatment landscape, and in particular, difficult-to-treat solid tumors where patients have poor outcomes and limited treatment options. We have activated our Jazz Care suite of services to help ensure Ziihera has robust access and reimbursement support for patients and healthcare providers that have questions and need assistance.
We have also set up flexible ordering and fulfillment options for customers to ensure that they can readily order Ziihera without delay or burden. Initial launch of second-line HER2-positive BTC will help establish Ziihera as a best-in-class HER2-targeted therapy that demonstrates significant benefit for patients. As Rob will speak to in the coming slides, we hope that this will be followed by a launch into the significantly larger first-line HER2-positive gastroesophageal adenocarcinoma, GEA, patient segment, pending positive data from our registration trial. With that, I will turn the call back to Rob to discuss next steps in our development plan to expand approvals to other HER2-positive tumors so more patients can potentially benefit from this therapy. Rob?
Thanks, Abizar. Starting on slide 34, clearly, we have a high degree of conviction in Ziihera's potential to transform the current standard of care in multiple HER2-expressing cancers. BTC is our first opportunity to bring this important new therapy to patients. Beyond second-line, our confirmatory phase 3 trial in first-line BTC is currently enrolling patients. We're also pursuing multiple phase 3 studies and indications beyond BTC. We have a phase 3 trial in first-line gastroesophageal adenocarcinoma ongoing, with top-line data estimated to be available Q2 2025. We also have initiated the phase 3 EMPOWER trial, which is designed to evaluate zanidatamab in combination with chemotherapy in patients who have progressed on or are intolerant to Enhertu. With this ongoing phase 3, we have the opportunity to be the first HER2-targeted therapy to demonstrate efficacy and safety in breast cancer patients post-Enhertu.
We also have multiple ongoing trials in early-stage breast cancer through our collaborations with MD Anderson Cancer Center and the I-SPY program. Additionally, we recently initiated a phase 2 pan-tumor trial. Zanidatamab monotherapy has shown promising activity across a range of tumor types, and this trial is an opportunity to efficiently generate additional data across a variety of HER2-expressing solid tumors. The trial is enrolling three cohorts of patients: a pan-tumor cohort, including patients with HER2-positive tumors who are HER2 treatment naive, as well as two cohorts of patients previously treated with T-DXd or Enhertu. One of these cohorts is enrolling HER2-positive gastroesophageal adenocarcinoma patients, and the other is enrolling HER2-positive breast cancer patients.
Overall, we're excited about the prospect of delivering zanidatamab to BTC patients in the near term, and we're executing on a robust development plan to evaluate zanidatamab in a range of HER2-expressing tumors where it has significant potential to improve care for patients. Now turning to slide 35 to close out our prepared remarks. The initial launch in second-line HER2-positive BTC will help us establish Ziihera as a best-in-class HER2-targeted therapy that demonstrates significant benefit for patients. Although it is important to highlight that this remains a rare disease with a limited number of addressable patients, our development program, including multiple registration-enabling studies, is focused on areas where we believe zanidatamab has the potential to emerge as the preferred HER2-targeted therapy. Enrollment of our phase 3 first-line trial in GEA remains on track, and we estimate top-line PFS data in the second quarter of 2025.
If positive, we expect this trial to support regulatory submission in the U.S. and Europe, with potential approvals in 2026. GEA represents a much larger patient population where we expect broad and rapid uptake. This rapid uptake may lay the foundation for future launches in various indications, including breast cancer, where the EMPOWER BC303 trial is already underway. We are also running trials and generating data in neoadjuvant and adjuvant breast cancer, including ongoing collaborations such as the pre-I-SPY and I-SPY programs, and our ongoing collaboration with the MD Anderson Cancer Center. We also just initiated the DISCOVER trial in previously treated HER2 indications, which can give us good insight into zanidatamab's effectiveness across a range of HER2-positive tumors, as well as incremental data on GEA and breast cancer in a post-Enhertu setting. So clearly, a lot to be excited about.
Zanidatamab has proven to be a unique, differentiated, and highly effective dual-targeted HER2 therapy that has the opportunity to redefine what is possible in HER2-positive tumors and provides the potential for a broad array of opportunities across the entire HER2-positive solid tumor categories. Zanidatamab represents a global opportunity for Jazz across multiple markets. Importantly, we are well positioned with our current oncology footprint, capabilities, and strong teams in place to realize this opportunity rapidly and efficiently. Before we open the line for questions, I want to take a moment to thank all of the patients and families involved in the zanidatamab clinical development program since its initiation, and to thank those physicians, nurses, investigators, and support staff who have helped ensure the trials have run smoothly, and lastly, I want to thank the Jazz team and its collaborators who have worked tirelessly to deliver this medicine to patients.
With that, I would like to now turn the call over to the operator for questions.
Thank you, sir, and once again, everyone, if you have a question today, please press star one on your telephone keypad. We'll go first to Jessica Fye, J.P. Morgan.
Hey, guys. Good afternoon. Thanks for taking my questions. A couple of things to help me kind of size the opportunity here. For the 3,000 U.S. HER2-positive BTC patient number on slide 29, is that incidence or prevalence, and how many of those 3,000 patients are second-line? And then just cutting that the next step further, is the mix of IHC2+ and 3+ in the trial reflective of the HER2-positive BTC patient population overall? Thank you.
So hey, Jessica, good to talk to you. It's Abizar. I'll go ahead and start answering the first question. I might refer to Rob on some of the demographics in the IHC3 trial versus real-world. In terms of the incidence, this is an incidence for annual incidence of BTC patients HER2-positive. That 3,000 number is both first-line and second-line patients. We don't break that out any further than that. So I think that was your first set of questions. I think your second was around whether IHC3+ in our trial corresponds to real-world.
I do think roughly it is real-world, Jess. And we know that the great majority are 3+. And I would remind you that while we didn't have a particularly large sample size in the 2+ patients, in the first-line BTC trial, we are allowing enrollment there. And that, of course, would be in combination with chemotherapy and immunotherapy. And we'll have an opportunity to study that population further.
We'll take the next question today from Jason Gerbery, Bank of America.
Hey, guys. Thanks for taking my questions. Can you just remind me the proportion of the 3,000 U.S. patients that you envision kind of fall into eligibility for second-line treatment and how you're thinking about sort of a duration of treatment assumption in BTC? And then lastly, just any evolving thoughts in GEA to proportion the split of PD-L1 positive versus negative subjects? Anything come out of the September FDA adcom that maybe from those pooled analyses that maybe makes you think a little bit differently about the split? Thanks.
Yeah. Hey, Jason. It's Abizar. I'll maybe start to address some of your first questions. Again, just to reiterate, we don't really break out the 3,000. There's a lot of assumptions that go into that. And so we just want to kind of leave it at the 3,000 as the annual incidence. We feel good about that number based on some public databases. And so that is the incidence population across front-line, second-line, and beyond. In terms of, I think, your question around how to think about treatment responses, et cetera, I'd probably refer to the data Dr. Pant presented in terms of some of the data on clinical efficacy and use that. And that's how we think about modeling the potential use of therapy over time in patients, appropriate patients. So I just refer to that data set that Dr. Pant presented earlier in the presentation.
Rob, I don't know if you want to outline a little bit around the GEA question.
Sure. Yeah, I do have a few thoughts on the GEA PD-L1 question. Certainly, we don't think that the breakdown in the KEYNOTE-811 necessarily represents the epidemiology. Probably patients who were tested PD-L1 positive may have been over-enrolled in that trial. I think that the prevalence is more likely to be 50/50, 40/60 based on the literature. And I would also point out that it is clear you mentioned the adcom. It is clear that not all patients will benefit from a PD-1 antagonist. And that does depend on, to some extent, the expression level of PD-L1. Having said that, our GEA trial, as you know, has two experimental arms: zanidatamab plus chemo, also zanidatamab plus tislelizumab plus chemo in the second experimental arm.
So we really think Ziihera is positioned in front-line GEA to be the HER2 treatment of choice, regardless of PD-L1 status or whether patients would be also given a PD-1 inhibitor. But the trial is set up to ensure that Ziihera would be the treatment of choice for those who are not getting a PD-1 or who would ultimately benefit from a PD-1.
Next up, we'll take a question from Annabel Samimy at Stifel.
Hi. Thanks for taking my question. I want to ask, I guess Ziihera is in a relatively unique position given it's the only one that's approved for HER2 second-line BTC. There are others that are listed in the compendia listing, but through a pan-tumor trial or a basket trial. So I'm just curious, from a price sensitivity perspective, maybe Dr. Pant can answer that. How do you think about the different options that you have, given the several recommendations and the compendia listing, and then the price sensitivity? How much does that play into it? And then I have a couple of follow-ups.
Yeah. Thank you. This is Dr. Pant here. So price compendia, I'm not sure about, but I can tell you as a clinician. So again, there are two kind of FDA-approved, if you look at it. One basket is trastuzumab deruxtecan, and the second one is zanidatamab, right? And this is, again, it's a personal choice by physicians treating. For me, the patients get GemCis a nd Durva or GemCis and pembrolizumab front-line. And that's chemotherapy with biliary tract cancer patients. So these patients, when they kind of get into the second-line setting, they're a little bit, they've been through chemotherapy. Their bone marrow is a little burnt out. So they may be feeling the effects of chemotherapy. So for me specifically, I would more think about doing Zanni second-line, and if they progress, then doing trastuzumab deruxtecan after that. But that's just me.
The reason for that is that I think that they get this kind of chemo-free interval in the middle before we introduce the next one. But again, it's a very personal choice among physicians. There are different choices available. But I think that way that's the way I would use these two drugs, zanidatamab and trastuzumab deruxtecan, as far as sequence is concerned. Did that answer your question?
I guess pricing sensitivity doesn't factor into it at all in that case.
Yeah. Not for me, unfortunately, because we're in a more academic center. So yeah.
Maybe I can jump in on that. Thank you, Dr. Pant. So when we look at the data that we've been able to generate with Ziihera, we're looking at value-based pricing. And the price is representing the value that we believe this new therapy is bringing to HER2-targeted cancer patients that have very few options for BTC. This is, of course, as we've talked about in the past, a very small initial patient population, but one that absolutely needs more treatment options.
We'll take the next question in the queue from Akash Tewari. Jefferies.
Hi. This is Anastasia on for Akash. Quick question on your HERIZON GEA trial. Do you have an interim PFS analysis built in? And how do you think success in that study could actually change the pricing of this drug, if at all?
Yeah. So I'll answer the first part. So we have one PFS analysis, and we have three planned overall survival analyses. So at the time that we do the one and only PFS analysis, we will do the first interim for overall survival. The purpose there is to provide any trends in overall survival that would support a submission on the basis of PFS for global health authorities. We then have a second interim analysis for overall survival that roughly corresponds to when we would have looked at overall survival under the prior smaller sample size. And then we have a final overall survival analysis. Remember, we changed it after we licensed from Zymworks.
We increased the sample size from 714 to 918, not on the basis of anything we were seeing from the trial, but mainly because we assessed that that trial was designed in a way that wasn't robustly powered for overall survival. We put in place a strategy that allowed us to maintain the timeline to the PFS readout and maintaining the first two looks at overall survival while adding a third and overall increasing the power for overall survival. So we were able to sort of have our cake and eat it too. And that seemed like a logical intervention to make.
And just to hit your last question on pricing, I would just note that when we price any of our drugs, we look at it based on value provided to patients, value provided to the treatment landscape. But we're not in a position right now to comment on pricing for future indications of Ziihera.
Your next question comes from Andrea Tan, Goldman Sachs.
Hi, everyone. Thanks for taking the question. Two for us, please. Now that Ziihera is commercially available, just curious how much disease or drug education you believe will be required to drive prescribing. And then also just wondering if there are any launch analogs you would point us to to help us think about the cadence of uptake in 2025 and beyond for second-line BTC here. Thanks so much.
Abizar, do you want to take that first question?
Oh, I'm sorry. I didn't take myself off mute. I apologize. This is Abizar. Thanks for the question. In terms of our disease education, we've been doing that prior to approval. We will continue with that in the biliary tract space, both through our kind of scientific exchange and our field sales personnel that have been doing that prior to approval and will continue to do that post-approval. However, now that we do have approval, we do feel there is enough awareness around biliary tract cancer. We want to continue to educate around now there's a really potent therapy for these HER2-positive patients. We do believe what we've seen in the market that there is a significant amount of testing already for HER2. It's obviously a very well-known biomarker.
So we want to shift a lot of our focus to educating around the product and its profile and what its attributes are. And so we will continue to always educate around disease, but we will heavily shift towards promoting and educating around the actual profile of Ziihera with our field sales team. In terms of launch analogs, we don't have one to point to in particular. This is a very, as we talked about, that incidence of 3,000 patients upfront. And there's a breakdown as you get into second-line patients. It is a smaller patient population. And so I think we're a little bit reticent to say there's one analog that's better than another. We know these patients, it's hard to predict where they cycle to and where they come from.
We do know that they are in both the academic institutions, the ones that Dr. Pant represents an asset as well as in the community setting. And so we are taking the approach that those patients are all over the U.S. and a variety of different accounts. It's hard to say how they're going to come in. And we just want to make sure we're ready to treat those patients, but it's hard to point to one specific analog that's going to mimic that.
Next up is Gregory Renza from RBC Capital Markets.
Great. Good afternoon, everyone. Congrats on the approval. Thanks for taking my question. Renée, maybe a question for you, as you definitely noted, just this being Jazz's third launch in oncology since 2020. And as you and Abizar and the team have discussed the overlap in the call universe, just curious what this means in terms of validation and your interest to really build the armamentarium in the solid tumor and oncology place to arm your field force with more products and more options for clinicians and for patients. And maybe just touch on how validating this is with maybe Jazz's more recent business development approach with zanidatamab a few years ago, what the approval means for that strategy. Thanks so much.
Yeah. Thanks for the questions, Greg. So I would say with respect to the team, we feel we're in an excellent position to support the launch. We've talked about our current footprint and infrastructure already being in an excellent position to be able to support Ziihera in this first stage with BTC and then with an approval eventually with GEA, be able to continue to call on similar treaters to be able to support the product. And Abizar has already commented on the education that we've been providing in the market. With respect to going forward, I mean, you would see all of the studies that Rob described in terms of looking at the potential with zanidatamab. We've said BTC is the first indication we expect to build on that. So beyond GEA, obviously, we have a study underway with breast, and we're really excited about the potential there.
Now have a pan-tumor study. So this is definitely an area that we're investing in in a meaningful way. As we look at corporate development, certainly, we believe that we executed an attractive transaction with Zymworks to bring zanidatamab into the company. And we've been thrilled both with the structure of that original transaction, but also in the way the data continues to look very positive in single agent, in combination, and heavily pretreated patients across multiple different tumor types. So that continues to give us confidence in the investments that we're making. And as we look at additional transactions, we're interested in oncology. We're also interested in building on our leadership positions in sleep as well as in epilepsy.
But we do believe we've been able to demonstrate in oncology across Zepzelca, Rylaze's successful launches, and now with Ziihera approval that we're able to make an impact here, an impact for patients, and have established quite strong relationships with our HCPs. And this is an area that we are committed to and continuing to expand.
The next question is Joel Beatty from Baird.
Hi. Thanks for taking the question. So the first one is on the 3,000 patient incidence. Is that 3,000 unique patients, or is there some patients that are counted twice, first when they're a first-line patient and then a second time, and then they become a second-line patient?
Yeah. They're not counted twice. They're unique. Sorry, Renée.
Go ahead, Abizar.
Yes. They're not counted twice. They are unique patients. So that is how we're thinking about the total patient set across first and second line.
We'll take the next question from Amy Fadia, Needham.
Hi. Good evening. Thank you for taking my question and congrats on the launch. My first question is just about maybe for Dr. Pant and Abizar is sort of how do I think about this distribution of patients across the academic and community setting? And with the recommendation added onto the NCCN guidelines, can you at least sort of qualitatively talk about the adoption curve as we should see across the two settings? And then just one thing we noticed on the NCCN guidelines, sort of the wording indicates that zanidatamab is added in category 2A, but useful in certain circumstances recommendations. So I didn't know what to make of that. So if you could sort of address that, that would be helpful.
If I can take the first question, as far as uptake, what I've seen over the last decade, actually in cholangiocarcinoma, biliary tract cancers, is that there has been a lot of testing has become fairly standard across, because at Anderson, we get a lot of patients from outside. We're a big cholangio center. Patients come self-referred, or we get patients sent from other physicians to look for trials, and I can tell you that I've really seen an uptake in sequencing and testing for these patients, so I think that kind of pool of patients that are already tested and they're looking at it and they have a target is growing.
So I think it's definitely there because, again, like I think somebody mentioned before about HER2 testing and in the community, they've been doing it for a long time, right, for other like for breast cancer and other. So it's, and I've seen a lot of testing because of FGFR inhibitors, IDH1 inhibitors, other targets in biliary tract cancer. That uptake, I've definitely seen. So it's fairly we're able to see that in the community as well as in academics, at least the testing part of it. The second question, maybe somebody else could answer on the NCCN. I'm not sure about the category thing.
Could you just repeat the question, Amy? Make sure I understand.
But the NCCN guidelines sort of just mentions useful in certain circumstances recommendation under category 2A. So I just wasn't clear if that meant anything.
Yeah. I mean, the category typically relates to the overall weight of the evidence and the trial design. So we're not surprised by the category because it was a single-arm trial for accelerated approval. Nonetheless, I think the data really do speak for themselves. I mean, these data are unprecedented to have, at least for the labeled population, over 50% response rate and a duration of response of 14.9 months. And so it's clearly recognized because of the rapid adoption into NCCN and the approval. And I think ultimately, this represents a really, really substantial advance for patients.
Your next question is from Mohit. Oops. Sorry. Did you have more, sir?
I was just going to add one last point on this question that just to kind of give you perspective where we think a lot of the patients do sit based on some claims and secondary data we've analyzed that help us think about commercializing the product. A lot of these patients do sit in the community setting, some in the academic, but in particular, frontline that progressive second line will be in the community. And we feel really confident with this NCCN categorization that continues to give confidence to those community settings to use the product, get it reimbursed, use it as appropriate, etc. So we feel really we're in a good position there.
We'll now take a question from Mohit Bansal, Wells Fargo.
Great. Thank you very much for taking my question. And again, thank you for this update. I have a question regarding GEA. So do we know in the first-line setting what percentage of patients are taking Herceptin in combination with the checkpoint inhibitor versus Herceptin plus chemo combination? And then when we see your first-line GEA data, how would you think about the PD-1 plus zanni plus chemo? Do you think that one should compare it to a 11 trial? Obviously, it's a cross-trial comparison, but or it would be just like the benefit of checkpoint on top of zanni? How would you think about it? Thank you.
Sure. I mean, so similar to the answer I gave before, it's clear now from the data that it's only patients who are clearly expressing PD-1 who are likely to benefit from a PD-1 inhibitor. What proportion of patients is that? And the literature is a little bit varied on this point, but it may be sort of 60-40. And so still a fairly large proportion of patients who would be getting for whom the standard of care would still be considered to be Herceptin and chemotherapy. And the way we're looking at this is zanidatamab is going to be positioned to be the HER2 therapy of choice.
We now have data, as we've mentioned in the presentation, across tumor types, across lines of therapy, as monotherapy in combination, in patients who are refractory or naive to HER2 therapies, really differentiating zanidatamab as the best-in-class monoclonal antibody and the only bispecific biparatopic monoclonal antibody. So we think it's going to be the HER2 agent of choice in front-line GEA, regardless of the PD-1 status, which doesn't predict at all for response to HER2 therapies. For those patients who are expressing PD-1 and are likely to benefit from a PD-1 inhibitor, they could get zanidatamab potentially in combination with a PD-1 inhibitor, ultimately based on the results of the ongoing phase three trial where we have two experimental arms, zanidatamab plus chemo or zanidatamab plus tislelizumab and chemo. And we think tislelizumab is also a best-in-class PD-1 inhibitor.
We'll take the next question from Jeff Hung, Morgan Stanley.
Thanks for taking my questions. In the past, you've said that there's overlap with your existing solid tumor footprint from Zepzelca. How many additional reps, sales reps did you hire for Ziihera? How many reps in total are now detailing the drug? And what proportion of second-line BTC physicians and patients can you cover with the sales footprint? And then for Dr. Pant, what proportion of your BTC patients would be eligible to be treated with Ziihera? And can you just talk through how you see the pace of adoption in your Ziihera treatment-naive patients playing out over the next 12 months? Thanks.
Sure. So I'll take the first question. In terms of our commercial footprint, we won't give any specifics about numbers and size. Obviously, it's proprietary. Now we think about our commercial model. What I'll say is that we leverage. I mean, there's a high level of synergy with what our current team currently does in the lung cancer space with Zepzelca for how we think about launching Ziihera in BTC and eventually GEA. I mean, as I mentioned earlier, a lot of solid tumor drugs are treated in the community oncology setting. Community oncologists, by definition, generally treat many types of solid tumors. They have multi-group specialties that have special tumor focus, but then within that same umbrella, they treat a wide variety of tumors. And so we feel that construct serves us well for lung cancer, as we think about GI cancers, across the specifics.
And so we feel really good. And it's been an incremental add, but a really incremental add and a really good synergy in terms of what we're doing in the solid tumor space. I'll let Dr. Pant take the second question.
Sorry, and could you repeat the question for me, please?
Sure. I was just curious what proportion of your BTC patients would be eligible to be treated with Ziihera and how you see the pace of adoption in the treatment-naive patients, the Ziihera treatment-naive patients playing out over the next 12 months. Thanks.
Yeah. So I think when you look at the HER2 patient population, it's about anywhere from like 10%-20% in all of BTC patients, maybe closer to that 20% mark because gallbladder can be high as 30%. So I think one of the things that we've seen is in the BTC patients, as I alluded to earlier, is that now people are actually testing a lot. And a lot of that is that because of the other targeted agents which have been approved over time. So we're seeing uptick in the patients tested. So we would think some of those BTC patients essentially have NGS done, and they can essentially go on Ziihera if they're HER2 positive. As far as it's a treatment-naive, this is for after frontline.
I don't know if I got the question properly, but this frontline is gem/cis with a checkpoint inhibitor. This would be for after frontline therapy, and the treatment-naive, obviously, we have the frontline HERIZON trial that we are doing the randomized phase three trial, so we would be for our treatment-naive patients, we are looking at putting them on the trial with HER2 amplified, and for second-line, obviously, who've been treated before, we are looking at them for putting them on Ziihera.
We'll go next to Joon Lee Truist.
Hey, thanks for taking our question. In the ongoing trials for first-line BTC, GEA, and breast cancer, do you also expect 3 plus HER2 expression would be needed to show clinical benefit, or are there other nuances that we should be considering? Thank you.
Yeah. So remember, we had a relatively small sample set in the single-arm monotherapy BTC trial that led to the accelerated approval. The other trials you mentioned, for example, in frontline BTC or frontline GEA, as well as the later-line breast cancer trial, are all in combination with other chemotherapy agents and in indications where there is maybe a clear track record for the value of HER2 therapies. And so I wouldn't necessarily read through a restriction in those indications to just the 3 plus. We are evaluating 2 plus and 3 plus, and we're optimistic that the benefit will be broad.
Your next question is from Balaji Prasad, Barclays.
Good afternoon. This is Sean for Balaji. Thanks for taking our question. Switching gear to breast cancer, your partner, ALX Oncology, recently announced the result of the phase 1B and phase 2 trial of the CD47 and zanni combo in advanced breast cancer at SABCS, which showed a 50% ORR, and given that this is a chemo-free regimen and the ORR result, if I remember correctly, is better than the CDK combo you announced at SABCS last year, so wondering what's the level of priority you view of this CD47 plus zanni combo in breast cancer? Thank you.
Yeah. Thanks for the question. I'm calling in from San Antonio where I'm attending the SABCS conference. And we are very excited to see these data presented and very encouraged by the strong results. We think it's just another set of data showing that zanidatamab is highly active in patients who are overexpressing HER2. Again, we see this activity as monotherapy, various combinations, and various lines of therapy. And one very important aspect of these data that I'd like to highlight is the strong activity in breast cancer patients who received a median of six prior therapies, inclusive of all patients having received En hertu. And I think this bodes well for our ongoing phase three trial where we are evaluating zanidatamab in breast cancer patients who have progressed or are intolerant to Enhertu .
The next question is from Gary Nachman, Raymond James.
Hi, this is Tejas Wein for Gary. Congrats on the launch, guys. So just to put a little bit of refinement on kind of the uptake, Dr. Pant, you've noted that a lot of community centers are testing for HER2, and they might be very comfortable treating BTC in the second-line setting. So maybe for patients that are already potentially on a second-line HER2-directed therapy in BTC right now with the Ziihera launch, who maybe are experiencing tox or progression, do you think Ziihera would be positioned maybe in third line or to kind of sub in if there's too much tox on current HER2-directed therapies?
Yeah. I think this, Dr. Pant, right? Question to me, right, about previous HER2 therapies, right? Like if they're on the HER2 therapy?
Yeah.
Yeah. Just like current patients.
So really, we don't have data on that for essentially any of the HER2 therapies. So it's just hard to say how the adoption would be. But normally, what happens is patients get some kind of anti-HER2 therapy, and physicians normally cycle through other anti-HER2 therapies just like with breast cancer and try to see if they can grab responses in the patients. That's what normally happens. So hard to think how the physician behavior would be, but I think that's how it's been followed traditionally for, let's say, breast cancer. So potentially could be for the same thing for BTC, but hard to say.
I'll just add another perspective.
Go ahead, sir.
I'll just add another perspective. I mean, Ziihera, when you read our label or indication, it's for previously treated HER2-positive IHC3+ BTC patients. So that's a fairly broad definition of whether they were previously treated in first line or they're in second line. Now, we think the majority of utilization will become in that second line after they've been on previous front-line therapy. However, if a clinician elects to take some of these second or third-line patients and treat them, yes, we think Ziihera is an appropriate therapy. It's labeled. But again, we think the majority and what we are educating today is around after they've been treated in the front line, we think this is a great therapy choice for them right there.
The next question comes from Joseph Thome, TD Cowen.
Hi there. Good evening. Thank you for taking my questions. Maybe the first one for Dr. Pant, I guess, is there any IHC3 plus HER2-positive BTC second-line patient identified that you would not treat with Ziihera for any reason? And what would be that reason? And then a little bit of a follow-on to June's question, maybe in the GEA study, are there pre-specified subset analyses for IHC3 plus populations and those that are IHC 2 + ISH+ ? Thanks.
Yeah. So I'll leave the second one to Rob. I'll answer the first one. It would be rare. For somebody who's actually treated patients on Ziihera in the phase one trial and now in the phase two, it's very well tolerated. These patients, it's a non-chemo option. These patients go about their day. Really, side effects are very easily manageable. So the one, if I had to guess, would be maybe somebody with a low ejection fraction that I wouldn't want to give it, congestive heart failure or something that I think could be a challenge. Or that's the main one that comes to mind. But for GE, I'll let Rob answer that one or somebody else from Jazz.
Yeah. Do you mind just repeating the second part of the question?
Yeah. Just when thinking about the IHC3 plus versus those patients that are IHC2 plus ISH plus, are there pre-specified subset analyses kind of delineating those populations in the GEA study that we'll read out next year?
Yeah. We'll be able to look at that. We don't necessarily separate them out as a pre-specified hypothesis test, but we collect the information. We'll be able to look at that as sort of an exploratory analysis.
Everyone, at this time, there are no further questions. I would like to hand the call back to Ms. Renée Galá for any additional or closing remarks.
Great. Thank you. With that, thank you for the questions. I'd also like to thank everyone for joining us today. We are excited to be able to deliver this new therapy to patients, and we look forward to keeping everyone updated on our progress across the entire zanidatamab development program. Thank you.
Once again, everyone, that does conclude today's conference. We would like to thank you all for your participation today. You may now disconnect.