Hello, everyone, and welcome. I'm pleased to introduce Dean Schorno, the CFO of Rigel Pharmaceuticals. The company has two commercial assets, TAVALISSE and REZLIDHIA, and they've got a program in development, R289, an IRAK1/4 inhibitor in lower risk myelodysplastic syndromes. Pleased to turn it over to you, Dean, and excited for your presentation.
Great. Thanks, [Mac], and thanks to Jefferies for having us to your conference again this year. And especially thanks to all of you for your interest in Rigel. So as I get started today, I'm be making some forward-looking statements, so I'd encourage you to see our rigel.com Investor site. You can find our full corporate presentation deck there, as well as our SEC filings for more complete information. Really excited today to describe our growing business and how we expect to grow the business into the future. We're a heme- focused business with commercial products that have been launched. We have TAVALISSE in ITP that has been on the market for about five years now. I'll describe that.
And then more recently, we in-licensed from Forma Therapeutics, REZLIDHIA, which is indicated in IDH1-positive relapse refractory AML. On the development and expansion side, we have an IRAK1/4 inhibitor program, R289, as well as multiple opportunities for olutasidenib and fostamatinib. In-license opportunity like the REZLIDHIA, in-license, I'd describe our key priorities for the business, key opportunities, and we think the time is right now for those type of opportunities. And then we have partnered programs like our program with Lilly that I'll describe. Wrapped around all of this is, we really, in our last quarterly call, we described really a path towards breakeven. We'll look to execute this business, grow sales thoughtfully, in a focused and disciplined way, you know, continue our development programs, again, on a path towards breakeven.
Growing sales of TAVALISSE. So I'll start with TAVALISSE. So TAVALISSE is indicated for adult patients with chronic ITP who've had an insufficient response to a prior treatment. That's almost always steroids. From a commercial perspective, we've really had some strong new patient starts in the recent past. During COVID, really, the full market was flat. It was flat as a result of access to patients as well as patients changing treatment therapies. So we're seeing really nice growth in the business and predictable growth into the future. A little bit about the market, the market opportunity. There's about 81,000 patients with chronic ITP. At any given time, about 37,000 of those patients are...
Their disease is not active, and they're just being watched by their physicians. About 20,000 are on steroids, often a high dose steroid, which is not a sustainable therapy, and that really leaves the 24,000 or so patients who are second through fifth plus line of therapy, and that's really where TAVALISSE is indicated. As you see on the right, if you go back to early 2021, about 40% of our activity, 40% of our new patient starts were in that third or in the fourth, fifth, and beyond segments. We've increased that to about 75%. We've done that through our promotional efforts, as well as just increased data presentation. Really important for a couple of reasons. One is you see that about 75% of the addressable market is in those earlier lines.
And the second reason is, you see on the left that, the efficacy, the response rates are higher in those earlier lines. So these are patients, their disease has progressed, they're earlier in their disease progression. You see that patients can get to 30% or 30,000+ platelets in 86%-94% of the time. So it's important that we continue that trajectory, and we're excited to see that. Once you have those responses, the right side shows the strong durability benefit of the drug. From a performance perspective, we continue to perform, you know, quarter-over-quarter, we've had record volume as well as record sales growth, about $24.5 million in Q3 of net product sales.
From an ex-U.S. perspective, we have great collaboration partners. We have Medison in Canada and Israel. We have Grifols in Europe and the Middle East, and Kissei in Japan and Asia. Kissei, about a year ago, released their Phase III data and launched in April in Japan. So all of those partners are selling drug at this point, ITP. Knight in Latin America, our newest partner, is working on approvals in Latin America. Let me move on to REZLIDHIA now, which is our newly launched product. So, back in July of 2023, we signed a worldwide collaboration agreement for in-license agreement with Forma Therapeutics to in-license REZLIDHIA. There was a February 2024 PDUFA date. Working with Forma, we were able to get it approved in December. We launched in December.
So this is really an example of an economically efficient but a high-quality late-stage asset that we were able to bring in, and I'll talk about the leverage of our commercial organization as I describe this. REZLIDHIA is indicated for adult patients with relapsed refractory IDH1 -positive mutations in AML. Before I get into the details of our commercial launch, a bit of background on AML and REZLIDHIA. So as you all know, very aggressive, you know, terrible disease. 20,000 patients will be diagnosed in the U.S. annually. About 11,500 of those patients will succumb to the disease. From an IDH1 positive perspective, 6%-9% of those patients are IDH1 positive, and the genetic testing is widespread available. Physicians know the status of their AML patients, high unmet need.
As you look to the right here, about 60% of those 20,000 patients will be fit and can undergo intensive chemotherapy. About 40% will be deemed to be unfit and not able to, you know, undertake that intensive therapy. Of that total population in the first line, over half of them will become relapsed or refractory, creating the orange boxes, which is where REZLIDHIA is indicated. From a study perspective, Forma did a great Phase II trial. They looked at eight cohorts, both in monotherapy as well as olutasidenib plus azacitidine. They looked across a variety of cohorts. The cohort one is what I'll focus on today, which was the registrational trial, the trial that resulted in the approval, which is relapsed refractory.
Important to note that we're continuing to do work on these other seven cohorts, and that can produce, you know, incremental publications as well as, you know, potential new areas of focus for Rigel. From a summary of the data perspective, when we in-licensed the program from Forma, it was really important that we found a differentiated product that met a critical unmet need. And these are the results that really showed that to us. A CR rate of 35%, median duration of response of 25.9 months, and that really was the, you know, the differentiating feature that was especially attractive to us. Having a durable benefit of over two years for these patients is truly outstanding.
92% of those patients were complete responders, and the median duration of response for those patients were 28.1 months. Transfusion independence was achieved and a well-characterized safety profile and no cardiac monitoring. This is a bit of the overview of that the opportunity, 20,000 patients split into fit and unfit. The result of it is the 6%-9% patients available is about 1,000 patients to Rigel. When we looked at the potential for the product, really we're able to, you know, check all the boxes, unmet need, the clinical data, as well as the safety profile. From a performance perspective, the business is growing, growing very nicely, and we're continuing to see strong growth, and we're pleased with that activity.
As we look at that growth, it's important to note, and I'll highlight our. We have a sales force of 49 people who are calling on the hem-onc doctors for both ITP and AML. ITP is really seen in the community setting, so that group really is focused on, again, ITP and AML. We established in July or had in place a fully functioning group of eight institutional business managers who were calling on the leukemia treatment centers and calling on those AML academic centers, the KOLs and AML. You see as the months progressed and as that team was in place in Q3, we're seeing more of the institutional academic centers ordering REZLIDHIA.
That we think will evolve as the KOLs, the academic institutions utilize the drug. That'll feed into the community setting, so we'll see a bit of a shift over time, but we're pleased with this direction and the utilization by those academic institutions. We noted on our last call that, you know, September was the highest new patient starts, and that's really of a function of those institutional business managers, as well as the continued data that we're putting out associated with the drug. So the launch has been very successful for us. As we look to Q4 and beyond, with respect to REZLIDHIA, we'll leverage that institutional business manager team. We'll continue key activities, speaker programs, conferences.
I'll describe a little bit about some of the abstracts we have at ASH in December. And then we'll look to continue on the right side, scientific activities, and continue to build the evidence and the presentations and publications across those other seven cohorts I described. And we'll also look to generate some real-world data, which we think will be important to the physicians. Moving on to our development programs focused on hematology, on oncology pipeline expansion. From a development opportunity, olutasidenib and fostamatinib, a wide range of development opportunities. For olutasidenib, there's AML, and I described in some of these other cohorts that there's opportunities, and we've seen data in combination therapy and frontline data, a variety of other places where IDH1 positive...
Mutations can have an impact in the disease state. Likewise, there's data in glioma as well as MDS that we're reviewing. As I said at the beginning, we'll pursue these opportunities in a, you know, focused and financially disciplined way. We think that there's opportunities for us to leverage both academic and government partners to assist in some of these strategic initiatives. From a fostamatinib perspective, again, a variety of opportunities. We'll focus on investigator-sponsored trials to move any of those opportunities forward.
From an in-license perspective, another driver of growth, again, in today's environment, we think there's an opportunity for us to continue to in-license, continue to utilize that late-stage development capability of Rigel, as well as that commercial capability, from launch to leveraging that hem-onc community capability, as well as the institutional capability. We'll look for differentiated assets across hematology, oncology, and other rare disease indications. We're really looking for late-stage programs that, again, we can bring across the finish line and commercialize. And from a synergy perspective, we'll look to certainly leverage the business. When we in-licensed REZLIDHIA, we added a net two people to the business, so it's just a sign of how we were able to effectively leverage our organization.
We'll look to do more of that. At ASH, the continued, continued interactions with the, with the physicians, with the KOLs, and continuing to get information out is just critical to the business, and we're, we're excited to have four, four abstracts, across olutasidenib. The first one being... Well, four abstracts in total, a couple with olutasidenib. The first one being with, AML patients, who are refractory or relapsed to hematopoietic stem cells to a prior IDH1 inhibitor, ivosidenib, or venetoclax. And so we've, we've got that data, and that data shows that, that REZLIDHIA effectively works in those populations. Secondly, you see that there's, there'll be data on olutasidenib in, in, MDS.
So as I said there, that in those the other seven cohorts, there was also MDS in there. Our partner in Japan, Kissei, will present data on their open-label extension study, which will show the duration of benefit and also the benefit of using the drug in second line. And then we'll do a for our IRAK1/4 inhibitor program, a trials in progress update. Moving on to that IRAK1/4. We have an IRAK1/4 inhibitor program, internally developed at Rigel, and it's unlike other programs that are typically IRAK4, we have an IRAK1 and 4 inhibitor, which we find and have shown that it can have a more complete suppression of a variety of cytokines. So we think it's a it can be a great tool for therapeutic management.
We're in the process of doing a Phase Ib, Phase IIa study in lower-risk MDS. This is a highlight of that study, primary endpoint being safety. We've completed the first two dose cohorts. We're in the third. This is enrolling nicely, and we'll look to, again, safety is a primary endpoint, but we'll look to efficacy in the secondary endpoints as well as PK and biomarker work on that. We expect to have data mid-2024, some preliminary data on this, so stay tuned for that. We're excited about the possibility here. With that data, there's the possibility of either continuing our development or, you know, potentially doing a collaborative, you know, license arrangement. We did one with Lilly for RIPK1, which I'll describe in a second here.
Here's the RIPK1. Again, like the IRAK1/4 program, this was internally developed at Rigel, and we have both a systemic program as well as. Lilly's launched that with the R552. They're doing work in rheumatoid arthritis, and so that program is progressing nicely. And there's also a basket of potential molecules that Lilly's assessing to that are blood-brain penetrant for CNS diseases. So, you know, a great example of a collaboration, you know, partnership with Lilly. That IRAK1/4 could be a program that we license into the future. From a financial perspective, you see, you know, both TAVALISSE and REZLIDHIA sales growing nicely.
On our quarterly call, we described it was a second quarter where we had about $32 million+ of operating expense. So we really are managing the business with that leverage I described, you know, as we brought in REZLIDHIA with the net two sales or net two to commercial people. We're finding that we're getting great leverage in the business, and we'll continue down that path as it is a priority, again, to do that development effort in a focused and financially disciplined way. We have $62.4 million of cash. So as we look to the 2023 and 2024 value drivers, to summarize, we'll expand the product sales. And again, it's really around awareness and adoption.
It's those 49, you know, 49 community-based sales representatives, the eight institutional business managers, and the continued flow of information we think will be real important as we expand the business. We have the opportunity to license the ex-US rights to olutasidenib. I described the suite of collaboration partners who are selling TAVALISSE for ITP. We've got that opportunity, and we'll look to find and secure those collaboration partners in Asia and Europe and elsewhere. Continued financial discipline, again, that's—it's important to the business and a priority for us. Development programs, we'll look to enroll the R289, and you will see that data in mid-2024. And we'll evaluate continued opportunities of olutasidenib as well as fostamatinib. In-license opportunities, actively pursuing it. So that's...
We again think that growing the business, one of the elements of growing the business can be through these in-license opportunities and the leverage that I described. And then we'll continue to support Lilly and other collaborators along the way. So I appreciate the time. We're absolutely always available for questions, so please feel free to reach out to us. Yeah. Thanks, everyone.