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Calithera Biosciences Inc (NASDAQ:CALA)
Q4 2019 Earnings Call
Mar 11, 2020, 5:00 p.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:

Operator

Ladies and gentlemen, thank you for standing by and welcome to the Calithera Biosciences Fourth Quarter 2019 Earnings Conference Call. [Operator Instructions] Please be advised that today's conference may be recorded. [Operator Instructions].

I would now like to hand the conference over to your speaker today, Ms. Jennifer McNealy. Thank you. Please go ahead ma'am.

Jennifer McNealy -- Vice President of Investor Relations and Strategy

Thank you, Danielle. Good afternoon, everyone. Welcome to our fourth quarter and year-end 2019 conference call. Joining me today are Susan Molineaux, our Founder, President and CEO; Keith Orford, Chief Medical Officer; and Stephanie Wong, Senior Vice President of Finance. We have issued our press release and it can be accessed through our website at calithera.com.

Before we begin, I would like to remind you that today's discussion will include statements about our future expectations, plans and prospects that constitute forward-looking statements for the purposes of the safe harbor provisions under the Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including those in the risk factors discussed in the Risk Factors section of our annual report on Form 10-Q filed with the SEC.

In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. While we may elect to update these forward-looking statements at some point in the future, we specifically disclaim any obligation to do so even if our views change. Please note that this call is being recorded.

And with that, I'll turn the call over to Susan.

Susan M. Molineaux -- Founder, President & Chief Executive Officer

Thanks, Jennifer. Good afternoon, everyone and thank you for joining us today on our fourth quarter and year-end 2019 conference call. At Calithera, we are building an integrated biotechnology company that develops novel small molecule oncometabolism drugs, drugs that are targeting tumor and immune cell metabolism pathways for the treatment of cancer and other diseases. By building a pipeline of novel therapeutic product candidates, we are creating multiple opportunities to positively impact clinical outcomes for patients and drive development programs toward commercialization. We are the first company to take a selective glutaminase inhibitor into the clinic and the first to demonstrate clinical activity in cancer patients.

Based on the compelling results for the ENTRATA trial in advanced renal cell carcinoma, which were presented at the European Society for Medical Oncology, or ESMO, meeting in September 2019. We believe we have demonstrated proof of concept for the activity of telaglenastat in renal cell carcinoma. We have now fully enrolled the telaglenastat CANTATA trial, a study with registration potential in renal cell carcinoma patients. This moves us a step closer to becoming a commercial biotechnology company.

We are pleased with the enrollment of CANTATA ahead of schedule and are grateful to the investigators and patients who helped us succeed our enrollment goal. We are, of course, closely monitoring the developments related to the coronavirus outbreak and its potential impact on Calithera and specifically the CANTATA trial. As you know, it is a fluid situation, making it difficult to determine the exact impact on the conduct of our CANTATA clinical trial. But that said, we do not anticipate any major challenges or treatment interruptions for our patients. Based on what we know today, we remain confident we can meet our top line data in late third quarter or the fourth quarter of this year.

This quarter, we also made progress toward initiating a randomized trial in first-line non-small cell lung cancer patients harboring genetic mutations in NRF or KEAP. Recent clinical data indicate that activation of the NRF/KEAP pathway results in very poor clinical outcomes, demonstrating that there remains a significant unmet need in this population. And we are on track to initiate this trial in the first half of the year with a potential for interim data in 2021.

Our arginase inhibitor, INCB001158 or INCB1158 is the first arginase inhibitor to enter the clinic. Arginase is an immunosuppressive enzyme expressed by immune cells in the tumor microenvironment. At the ESMO meeting in September 2019, the first efficacy data for this compound represented demonstrating activity and providing proof of concept for arginase inhibition for the treatment of cancer. We are pleased with the progress of this program as we seek to develop a first-in-class product for patients with multiple types of solid tumors.

Last year we completed a Phase 1 trial in healthy volunteers for our wholly owned arginase inhibitor, CB-280, for the treatment of patients with cystic fibrosis. Our Phase 1b trial in people with cystic fibrosis is on track to start enrollment in the first half of the year. Beyond our three clinical stage programs, we have a broad pipeline and a productive R&D team. We remain focused on producing novel drug candidates with the potential to be highly differentiated new therapies in areas of unmet need. Our most advanced preclinical stage program are in immuno-oncology. We have promising preclinical data with CB-708, our oral small molecule inhibitor of CD-73, but at this time, we have chosen to deprioritize development of this program and we do not have plans to advance CB-708 into clinical trials this year. Meanwhile, we are continuing preclinical studies with our small molecule inhibitor of IL4I1 and novel target involved in tumor immunosuppression.

And with that, I will pass the call over to Keith for additional details on our clinical programs.

Keith Orford -- Chief Medical Officer

Thank you, Susan. Let's begin with a more detailed update of telaglenastat, our glutaminase inhibitor and our most advanced product candidate. We are currently focused on forging a clinical and potentially commercial path for telaglenastat in renal cell carcinoma. In the quarter, we announced completion of enrollment of CANTATA, a global randomized, double-blind trial of telaglenastat in combination with cabozantinib in the second- and third-line RCC patients. CANTATA enrolled 444 patients ahead of schedule, demonstrating the significant unmet need for advanced RCC patients in the second- and third-line setting.

CANTATA is designed to evaluate the efficacy and safety of telaglenastat in combination with cabozantinib versus placebo, plus cabozantinib. In clear-cell RCC patients, who have previously received one or two prior lines of therapy including at least one prior anti-angiogenic agent or the ipilimumab-nivolumab combination. Patients were randomized in a 1:1 ratio to either telaglenastat plus cabozantinib or placebo plus cabozantinib. Patients were stratified by IMDC risk category and prior treatment with anti-PD-1, PD-L1 therapy. The primary endpoint is progression-free survival by independent review. Overall, survival will be assessed as a key secondary endpoint. The trial is designed with registrational intense, and we remain on track to report top line results of CANTATA in late third quarter or fourth quarter 2020.

We also believe telaglenastat has the potential to be developed in patients with NRF2/KEAP1 mutations. Multiple in-vivo preclinical models have demonstrated that activation of this pathway through a loss of function in KEAP1 mutation or a gain of function in NRF2 mutation accelerates tumor formation and spread. In addition to make it tumor models more aggressive, the activation of the NRF2/KEAP1 pathway also makes them sensitive to the inhibition of glutaminase activity by telaglenastat. An NCI sponsored trial evaluating single agent telaglenastat in patients with solid tumors that have NRF2 or KEAP1 mutations is currently ongoing.

Recently presented clinical data have demonstrated that activation of the KEAP1/NRF2 pathway results in very poor outcomes in non-small cell lung cancer patients receiving front-line standard of care chemotherapy or chemo immunotherapy. Based on this recently presented data and the unmet need of this population, we have designed a randomized trial in lung cancer patients, which we expect to begin in the first half of 2020. The study will evaluate telaglenastat in combination with standard of care therapy, chemo plus pembro in approximately 120 first-line metastatic non-squamous lung cancer patients with tumors that harbor mutations in either KEAP1 or NRF2. The study will include an initial safety run-in period and co-primary endpoints are safety and investigators set progression-free survival. An interim analysis is planned in 2021.

Next, the arginase program, INCB001158, also known as 1158 is an investigational first-in-class immuno-oncology metabolic checkpoint inhibitor targeting arginase, an immunosuppressive enzyme secreted by myeloid-derived suppressor cells, or MDSCs, to block T cell activation in tumors. 1158 is being developed with Incyte in a co-development, co-commercialization collaboration. 1158 is being evaluated as monotherapy as well as in combination with pembrolizumab across eight cohorts of withe different types of metastatic or locally advanced cancer is not amenable to local therapy. The first data from this study were presented at ESMO in September, 2019.

Dose escalation with monotherapy to find the recommended Phase 2 dose of 1158 was followed by expansion in three cohorts non-small cell lung cancer, colorectal cancer and the basket arm of solid tumors. Following the dose escalation of 1158 in combination with pembro eight cohorts were expanded or enrolled patient populations that were PD-198 and four enrolled patient populations that were PD1 refractory. PD-1 refractory patients had to be on a checkpoint inhibitor-based therapy and failing to derive benefit at the time of study entry, which means that they have active disease progression or prolong stable disease without a response.

The colorectal monotherapy and MSS colorectal combo cohorts advanced to Simon stage 2 and data on both cohorts were presented at ESMO. The PD-1, PD-(L)1 naive had a net cohort -- combo cohort has also advanced to stage 2 and is actively enrolling. As the colorectal cohorts were the most mature at the time of data cut off, they were the focus of the presentation. Responses were observed in both the combination and monotherapy cohorts. We were also pleased to see increases in total intratumoral CD8+ cells following treatment with 1158 plus pembrolizumab in MSS colorectal cancer patients, with the increase is occurring most notably among those patients that derive clinical benefit. We believe this provides proof of concept for arginase inhibition in the treatment of cancer.

The second ongoing clinical trial is evaluating 1158 in combination with three different chemotherapy regimens, FOLFOX, gemcitabine/cisplatin and paclitaxel in patients with ovarian, endometrial, colorectal, gastroesophageal and biliary tract cancers. An additional trial in multiple myeloma patients, treating patients with 1158 plus daratumumab or daratumumab alone is also ongoing. We are pleased with the progress of this program and we look forward to additional data updates from the 1158 program in the future.

We are also developing an arginase inhibitor outside of oncology, CB-280 is a novel arginase inhibitor in development for the treatment of cystic fibrosis. Under our collaboration agreement with Incyte, we retained worldwide rights to develop and arginase inhibitors in specific non-oncology rare disease indications, including cystic fibrosis. Arginase has been positive to play critical role in the pathophysiology of cystic fibrosis, as well as several other non-oncology diseases. CF patients have neutrophil infiltrates in their lungs and these neutrophils secrete high levels of arginase. High arginase activity depletes arginine, which in turn depletes nitric oxide. Nitric oxide, or NO, has potent antimicrobial activity and exogenous NO has been shown to improve lung function when administered to CF patients. We hypothesized that inhibition of arginase with CB-280 can restore normal arginine and NO levels and improve lung function in CF patients. Concept that is supported by previous proof of concept clinical trials.

The Phase 1 clinical trial to evaluate the safety, tolerability and pharmacokinetic profile of oral CB-280 in healthy volunteers has been successfully completed. A Phase 1b clinical trial in CF patients, which is expected to start enrollment in the first half of 2020 will test multiple doses of CB-280 compared to placebo and approximately 30 adult CF patients to determine a safe dose range for CB-280. Patients with any CFTR mutational status will be eligible for the study. Patients will receive CB-280 or placebo for 14 days; lung function, NO production and speed microbes will be evaluated. A dose-finding expansion of this study is planned in which additional cohorts of patients will receive different doses of CB-280 or placebo for 28 days in order to select the optimal dose of CB-280. For the entire study, patients will continue their existing therapies for CF, including CFTR modulators. We plan to present data from this trial in 2021.

With that, I'll pass it over to Stephanie for an update on our financials.

Stephanie Wong -- Senior Vice President of Finance and Secretary

Thank you, Keith, and good afternoon, everyone. Detailed financial results for the fourth quarter and year-end 2019 were included budget in today's press release. I will briefly review our results on this call. Calithera ended the year well capitalized. Our cash and investments were $157.4 million at December 31, 2019, and we expect to utilize $75 million to $85 million in 2020. We believe our cash position enables us to drive our clinical programs to meaningful value inflection points.

Research and development expenses were $76.3 million in 2019, compared to $66.2 million in 2018. The increase in 2018 to 2019 was primarily in the telaglenastat program, including for our CANTATA trial where we completed enrollment in 2019 and in our 1158 program. Research and development expenses for the fourth quarter 2019 were $17.9 million, compared to $17 million for the same period last year.

General and administrative expenses were $16.6 million in 2019, compared to $13.3 million in 2018. The increase from 2018 to 2019 was primarily related to higher professional services costs mainly for legal and accounting services, and higher personnel-related costs, primarily from higher headcount. General and administrative expenses for the fourth quarter 2019 were $4.6 million, compared to $3.2 million for the same period last year.

Interest and other income, net $3 million in 2019, compared to $2.6 million in 2018. Interest and other income, net for the fourth quarter of 2019 and 2018 were $0.7 million.

Net loss for the quarter ended December 31, 2019 was $21.7 million. And with that, I will now return the call back over to Susan.

Susan M. Molineaux -- Founder, President & Chief Executive Officer

Thank you, Stephanie. And with that, operator, we're happy to open the line for questions.

Questions and Answers:

Operator

[Operator Instructions] Our first question comes from Mohit Bansal with Citi. Your line is now open.

James -- Citi -- Analyst

Hi guys, this is actually James [Phonetic] on for Mohit. I had a question about the long trial on the liquid biopsy to identify the NRF2/KEAP1 patients. Are the bias results limited to just binary outputs, I guess as it is just positive or negative for NRF2/KEAP1 activation or is there some sort of quantitative output that can help track changes in the, I guess the levels of NRF2/KEAP1 or the amount of circulating tumor cells?

Keith Orford -- Chief Medical Officer

Yeah. Hi, James. Great question. So, no, it's not just a binary outcome or results on the assay. So, we'll get the results, first of all, for a number of other mutation status across all of the genes in the panel. But also, it will be a quantitative result and we will be following or taking samples during the study that would allow us to do just what you're talking about, following circulating DNA levels to look for potential response.

James -- Citi -- Analyst

And then, and just like a quick second question. Maybe a bit early, but you guys talked about being one step closer to be a commercial company, but can you talk about some of the, I guess, early planning or strategies around telaglenastat for RCC?

Susan M. Molineaux -- Founder, President & Chief Executive Officer

For commercialization, we've been starting to put a whole plan in place for a potential launch. As you know, we have fast track status. And so if the CANTATA data at top line were positive, we would move toward filing and submitting NDA, and with again potential for priority review. And on this timelines, we've been readying the company for a whole set of pre-commercial activities and we have started to settle them prior to seeing the top line results, but of course, a lot more activities will occur after we see top line results if they're positive.

James -- Citi -- Analyst

Awesome. Thanks, guys.

Operator

Thank you. Our next question comes from Jonathan Chang with SVB Leerink. Your line is now open.

Jonathan Chang -- SVB Leerink -- Analyst

Hi, thanks for taking my questions. First question, you've refined your guidance around the CANTATA readouts slightly to late 3Q to 4Q from second half previously. Any color on the more granular timeline, it sounded like it's not coronovirus-related?

Keith Orford -- Chief Medical Officer

No, it's really just the fact that as the data mature, as we analyze the data, we can get -- we're able to tighten up our guidance essentially. So, it's really just based on what we've seen in terms of event rates and allows us to project a little more accurately.

Jonathan Chang -- SVB Leerink -- Analyst

Got it. Second question on the lung cancer study. Can you talk about your expectations for enrollment and what investors should expect regarding the nature of the interim data in 2021?

Keith Orford -- Chief Medical Officer

In terms of enrollment, so we have taken the -- our efforts to open the study and to operationalize the study include a few specific things that are meant to optimize enrollment and to accelerate enrollment. Given that, we're looking at a subset of patients in the front-line setting, which is a significant proportion in the order of 20% of patients -- non-squamous patients. So it's a significant population, but obviously we still need to screen and then only enroll those patients that screen positively. So for those purposes, we put in -- into place a liquid biopsy that we will make available to all sites to screen patients in order to make this study attractive and also just to facilitate finding these patients on a timely basis prior to starting their front-line therapy. So that's one key element is that we've making this and the liquid biopsy available.

Secondly, we are going to open a significant number of sites in order to be able to identify these patients. So, we are aggressively identifying and opening sites for the purpose of keeping enrollment at a rapid pace. So there is an initial safety run in as we mentioned, so enrollment will go until we've demonstrated that the regimen is safe, which we expect it will be -- and then it will be open to full enrollment. The expectation is that, that will allow us to get to our interim analysis, which is, it's going to be on approximately half of the patients, a little bit under half the patients. When we have results from those patients, we will be able to do an interim analysis and we expect that would be in 2021.

Jonathan Chang -- SVB Leerink -- Analyst

Got it. And then just lastly on your cash position. Any color on how we should be thinking about runway at burn in 2020?

Stephanie Wong -- Senior Vice President of Finance and Secretary

I'm sure, Jonathan, we don't really guide to cash runway, but our cash guidance for this year is $75 million to $85 million. And so we ended the year at $157 million.

Operator

Thank you. Our next question comes from Swayam [Phonetic] Ramakanth with H.C. Wainwright. Your line is now open.

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Thank you. Good afternoon, ladies. Couple of quick questions. In terms of the NCI sponsored study that Keith was referring to, could you give us a little bit of color in what cancers this study is being conducted, and anything on data expectations and if the data is positive, what sort of indications would look interesting for Calithera to take over and run them?

Keith Orford -- Chief Medical Officer

Yeah. So this is a study that's looking at actually a couple of different mutations in NRF2/KEAP1 or two of the key mutations, but it's identifying patients with these specific mutations not limited by their histology. So it's essentially open to patients with solid -- many solid tumors that have documented mutations in NRF2/KEAP1 as well as a few others as well. So, it's not restricted by tumor type. It's really a signal seeking study that would potentially provide us with data that would support development in any of these tumor types or even conceivably in a tissue agnostic approach that where we look for patients with those specific mutations. And that could be -- monotherapy or could be in combination with standard therapies.

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Okay. And anything on the data expectations, do you have any?

Keith Orford -- Chief Medical Officer

It's difficult to predict the timing. So CTEP moving along with the program, and they've been a great partner at least from the -- we've been reviewing -- we've reviewed the protocol. But obviously they run this study completely independently and it's on their timelines. So we really can't speak to that.

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Okay. And then on 1158, can you give us some color as to when we could expect the next update from Incyte on this?

Keith Orford -- Chief Medical Officer

So that study continues. Actually those studies, there is multiple studies, the one-on-one study, which is our study with pembro. There is the chemo combination study and then they also have their myeloma study and a study in Japanese patients. All these studies continue to enroll. Given that this is a joint development collaboration, we aren't able to provide that guidance in the absence of sort of our joint agreement on that. So at this point, no, we're not able to provide further color on that.

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Okay. And Susan, this is a strategic question, when quite a few of the companies are going after the CD73 target and they're not really -- hardly through their Phase 1 study most of these folks. So what's the reason for you to be prioritize CB-708? Is it something to do with science or is it something to do with resources?

Susan M. Molineaux -- Founder, President & Chief Executive Officer

It doesn't have anything to do with the science. We have a really potent and selective oral compound that inhibits CD73, so we are quite happy with the preclinical data and toxicology data we've generated on the molecule. Right now, with the entire adenosine pathway being interrogated across multiple targets, not just CD73 and no definitive data pointing the way as to what combination studies one should do in which tumor types in order to move forward not only would we be in a competitive landscape with other molecules and companies who are ahead of us, but also the path would have to be quite broad. And so, we're still open to the concept of going into the clinic, if we have resources from a partner to help us. But right now on our own, we have a lot of other priorities on our other programs in clinical that we would like to pursue.

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Thank you for that, Susan. I appreciate taking all my questions.

Susan M. Molineaux -- Founder, President & Chief Executive Officer

Thank you.

Operator

Thank you. Our next question comes from Matt Phipps with William Blair. Your line is now open.

Matt Phipps -- William Blair -- Analyst

Hi, thanks for taking my questions. Keith, I guess first on the lung cancer trial. How is this -- can you give us anything about how this is powered, I mean how much benefit do you need to see here on top of standard care considering we know that these patients do support with standard care? And then in the previous OPDIVO trial, there were some non-small cell lung cancer patients, they were, I guess kind o f rescue, but they previously had KEAP1, and have you really go back and look at see if any of those patients had any of the NRF2/KEAP1 mutations, just see if there is there anything you can go off of? I don't think it with a ton of patients in the study.

Keith Orford -- Chief Medical Officer

Right. So in terms of the study design, so it's 120 patients. As you mentioned, the outcomes for these patients based on data that have been recently presented as quite core. So even with the 120 patients, isn't a huge study. But it's also not a small study. We think we'll be able to see a reasonable increase, just not powered like like a Phase 3. So we're not talking about to send an alpha here for the design, having said that, of like 0.05. Having said that, with a significant increase in benefit, then you would be talking about interesting statistics of that sorts. And we've tried to design the study large enough so that a home run would be of interest, but we would also be able to see a recent sized signal. So let's -- two-month benefit or better, that would give us evidence to move forward into a subsequent randomized study.

Matt Phipps -- William Blair -- Analyst

Got it. And then anything on those previous...

Keith Orford -- Chief Medical Officer

Right. So, yes, we did have patients on that study that have the pathway activated through mutations. We haven't presented those data publicly, but we're certainly aware of them, and were part of our thinking as we plan to go forward with the current study. And I think the plan at some point will be to present those data as well.

Matt Phipps -- William Blair -- Analyst

Great, thanks. You guys have shown recently a new slide in the deck that have kind of some preclinical experiments on cell lines that have primarily the KEAP1 mutated lines. There is -- most are very responsive. There's a couple of that aren't. And I guess, have you looked at those lines and another mutation that may be -- could be one that you want to watch out for is not predicting response, I assume a lot of space to cell line and patients will have multiple mutations. But just kind of wondering if you're trying to tease out maybe why some of those cell lines didn't appear to be as responsive?

Keith Orford -- Chief Medical Officer

So we haven't done a lot of work on that, but we have seen that the one I think it was the least sensitive cell line when analyzed for activation of that pathway did not activated, as well as the other cell lines. So while it does -- it did, however, the mutation. It didn't act and it didn't show itself through its gene expression profile to have fully activated the pathway. I think that's probably about as much as we can say there. And Susan, if you have anything else to add?

Susan M. Molineaux -- Founder, President & Chief Executive Officer

No, that's true and I would also add that as part of our study, we will be looking at the biopsies of patients and not just the actual mutational status of the patients and we'll be able to see through looking at gene expression profile whether those pathways are really on or not. So that's just one example out of many cell lines where we knew that they had an activating mutation and yet they didn't activate the pathway. We don't know specifically why in that cell line. We know it's rare, but other cell lines probably we will be able to deliver any patients that carried a mutation, but didn't activated the pathway in our clinical studies.

Keith Orford -- Chief Medical Officer

Yeah. That maybe gene expression profiles or that could be immunohistochemistry.

Matt Phipps -- William Blair -- Analyst

Great. Thanks so much for taking the questions.

Keith Orford -- Chief Medical Officer

Yeah. Thanks, Matt.

Operator

Thank you. Our next question comes from Jim Birchenough with Wells Fargo Securities. Your line is now open.

Jim Birchenough -- Wells Fargo Securities -- Analyst

[Indecipherable] Just following up on the lung cancer trial for telaglenastat, I know the protocol excludes patients who have actionable mutations. So can you just talk about what the overlap is between actionable mutations as well as KRAS P53 in that 20% of patients who have the pathway activation on the mutation of interest?

Keith Orford -- Chief Medical Officer

Yes, sure. So there is a -- so most of the patients who have KEAP activated do not have actionable mutations. So there's sort of a -- they're not mutually exclusive, but there is a reduced rate of actionable sort of EGFR our tight mutations in the KEAP mutant patients. So while you will find overlap, it's less common among the KEAP mutant patients to have actionable mutations.

And then in terms of the KRAS KEAP overlap, Susan correct me if I'm wrong, but I think about it -- I think around a third of the KEAP mutations also have KRAS mutations. So there is definitely overlap there, but actually it looks like the majority of patients do not have KRAS but a significant proportion do.

Jim Birchenough -- Wells Fargo Securities -- Analyst

Thank you. And then the preclinical data suggests that whether KRAS is present or not, those cells are equally sensitive to telaglenastat.

Keith Orford -- Chief Medical Officer

Yes. So there is -- the preclinical data are there is different -- there is some different models and different opinions on that, but in general from our take on it is that KRAS is not necessary. And then the clinical data suggests that the outcomes are not KRAS-dependent. So you don't have to be KRAS being to have or outcome. So our take on the data is that KRAS is not a problem, but it's also not necessary in terms of likelihood of response to glutaminase inhibition.

Jim Birchenough -- Wells Fargo Securities -- Analyst

And then I think the patients are going to be stratified based on STK11/LKB, would you expect that to account for 50% of these patients or will it be a small fraction?

Keith Orford -- Chief Medical Officer

Yeah, the STK11/LKB is a -- it's a significant proportion. I'm trying to remember, it might be in the same range as KRAS, it's probably around a third of the patients are likely to be STK11 mutants and that's a range where you do want. If it's 95% or if it's 5%, it's actually not that important to stratified, but when you're in that more intermediate range, it's more relevant to stratify.

Jim Birchenough -- Wells Fargo Securities -- Analyst

And then just last one on the lung study, so you talked about the interim analysis. If you do see a profound benefit, do you have the opportunity to think to expand this study for registration purposes or you would have to close the study and start a brand new study?

Keith Orford -- Chief Medical Officer

Yeah. So we would think that there are -- all those options are possible. So we can either open a new study or even just amend the current study. We would at that time -- at that point, likely select a specific assay to screen for that all patients will be screened by. But we do think we could conceivably amend or doing new study. Most likely, this is something we would talk through with FDA and get their inputs.

Jim Birchenough -- Wells Fargo Securities -- Analyst

Sure. And then just last one for me, for the telaglenastat brand combinations, should we expect to safety data this year or some efficacy ahead of cohort expansions?

Keith Orford -- Chief Medical Officer

Yeah, I mean -- those studies are ongoing. They are through -- getting through their dose escalation and do expansions. So, we haven't guided specifically on the timing around data presentation. So, I would say it wouldn't be impossible, but we're definitely are guiding at this point. So, definitely doing a presentation later this year.

Jim Birchenough -- Wells Fargo Securities -- Analyst

Right. Thank you very much, and we'll miss each other at AACR this year, unfortunately.

Keith Orford -- Chief Medical Officer

Thanks.

Operator

Thank you. I'm not showing any further questions at this time. I would now like to turn the call back over to Jennifer McNealy for any closing remarks.

Jennifer McNealy -- Vice President of Investor Relations and Strategy

Thank you, Danielle. And thanks all for joining us and have a great evening.

Operator

[Operator Closing Remarks]

Duration: 38 minutes

Call participants:

Jennifer McNealy -- Vice President of Investor Relations and Strategy

Susan M. Molineaux -- Founder, President & Chief Executive Officer

Keith Orford -- Chief Medical Officer

Stephanie Wong -- Senior Vice President of Finance and Secretary

James -- Citi -- Analyst

Jonathan Chang -- SVB Leerink -- Analyst

Swayampakula Ramakanth -- H.C. Wainwright -- Analyst

Matt Phipps -- William Blair -- Analyst

Jim Birchenough -- Wells Fargo Securities -- Analyst

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