Good morning. My name is Chris and I will be your conference operator today. At this time, I would like to welcome everyone to the Karyopharm Therapeutics' Third Quarter 2019 Financial Results Conference Call. There will be a question-and-answer session to follow.

Please be advised that this call is being recorded at the company’s request.I would now like to turn the call over to Mr. Ian Karp, Karyopharm’s Vice President, Investor and Public Relations..

Thank you, Chris and thank you all for joining us on today’s conference call to discuss Karyopharm’s third quarter 2019 financial results and business update. This is Ian Karp and I’m joined today by Dr. Michael Kauffman, our Chief Executive Officer; Dr. Sharon Shacham, President and Chief Scientific Officer; Mr. Mike Mason, Chief Financial Officer; Mr.

Chris Primiano, Chief Business Officer and General Counsel; Mr. Perry Monaco, Senior Vice President of Sales; and Dr. Jatin Shah, Chief Medical Officer.On the call today, Dr.

Kauffman will provide an overview of key recent corporate developments, Perry will give an update on the initial commercial launch of XPOVIO, and Mike will highlight the third quarter 2019 financial results.

We will conclude with the Q&A portion of the call.Earlier this morning, we issued a press release, detailing Karyopharm’s results for the third quarter 2019. This release as well as an accompanying slide presentation, are available on our website at karyopharm.com.

Before we begin our formal comments, for those following along in the slide presentation please turn to Slide 3 and I'll remind you that various remarks we will make today constitute forward-looking statements for purposes of the Safe Harbor provisions under the Private Securities Litigation Reform Act of 1995.These include statements of our future expectations, clinical developments and regulatory matters and timelines, the potential success of our products and product candidates, including our expectations relating to the commercialization of XPOVIO, financial projections, and our plans and prospects.

Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including those discussed in the Risk Factors section of our most recent quarterly report on Form 10-Q, which is on file with the SEC and in other filings that we may make with the SEC in the future.Any forward-looking statements represent our views as of today only.

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.

Therefore, you should not rely on these forward-looking statements as representing our views as of any date subsequent to today.In addition, please note that any references we make to clinical trial data during today's discussion refer to interim unaudited site data, unless otherwise specified.

We will also be providing on this call, non-GAAP outlook for operating expenses 2019, which can only be provided under non-GAAP basis without unreasonable efforts.I'll now turn the call over to Dr. Michael Kauffman, Chief Executive Officer, and please now turn to Slide #4..

Thank you, Ian, and good morning, everyone. Before I provide details of our third quarter performance, I think it is important just as a bit of context in terms of where we are on our journey towards becoming a leading oncology focused pharmaceutical company.

Karyopharm's mission is clear, to help improve the lives of patients with cancer and other serious diseases.Our ability to effectively fulfill this mission is predicated on three fundamental principles.

First, our company was founded on and remains intensively committed to advancing innovative science and resilient new discovery, development and commercialization of medicines with novel mechanisms of action.Our core area of scientific focus, nuclear export dysregulation is increasingly recognized as playing a fundamental role in oncogenesis along with other conditions, and XPOVIO is now the first and only approved drug targeting the inhibition of XPO1 protein which plays a critical role in many cancers.

This novel approach was recognized specifically in myeloma with a recent publication of the STORM results in the New England Journal of Medicine.Secondly, we aim to meaningfully and urgently impact the treatment of patients with relapsed or refractory multiple myeloma.

We were extremely pleased with the FDA's Accelerated Approval decision in July and you will hear more about XPOVIO's early commercial success in a few minutes from Perry.

Additionally, we aim to expand XPOVIO's role in multiple myeloma treatment and eagerly await the top line results from the Phase 3 BOSTON study in early 2020.Finally, we believe XPOVIO and our follow-on investigational medicines have the potential to impact patients with high unmet medical need candidates beyond multiple myeloma.

To that end, in the near term, we expect to submit an NDA requesting accelerated approval in DLBCL before the end of this year. And we remain highly encouraged about potential solid tumor indications for XPOVIO, the first in liposacroma with Phase 3 field data expected mid next year.

We remain truly excited about what the future has in store for Karyopharm and the patient we are serving.With this as a backdrop, let's now turn to the progress we've made specifically in the third quarter which is highlighted on Slide 5.

The past few months have been a remarkable period for Karyopharm following the accelerated approval on July 3, from the FDA with the first shipments of XPOVIO taking place on July 9.XPOVIO launch is off to a very strong start and we are pleased to report $12.8 million in net product sales for the third quarter.

The demand for XPOVIO has been driven by a broad base of healthcare providers with over 300 unique physicians or accounts having prescribed XPOVIO and over 500 prescriptions fulfilled in less than three to four months on the market.We also continue to make additional important clinical and regulatory progress in the quarter.

Most notably, the results from Phase 2B STORM study evaluating XPOVIO in patients with triple class refractory multiple myeloma were published in the New England Journal of Medicine in August and additional supportive clinical data highlighting the activity of XPOVIO with dexamethasone and with other anti-myeloma agents were presented at the 17th International Myeloma Workshop in September.As we look out to some improvement milestones over the coming months, we remain on track to submit an NDA in DLBCL by the end of 2019 and importantly, we expect top line data from the Phase 3 BOSTON study to be reported in early 2020 with specific timing continued on the occurrence of progression advance, the primary endpoint of this study.

Additionally, we continue to anticipate a decision from EMA on our Marketing Authorization Application for selinexor in patients with heavily pretreated multiple myeloma in early 2020.Finally, on the financial front in the third quarter, we secured additional capital to support the ongoing commercialization and development of XPOVIO along with our other products, specifically entering into Royalty Agreement with HealthCare Royalty Partners for up to $150 million in capital.

This additional capital contributed in Karyopharm ending the quarter with approximately $270 million in cash, cash equivalents and investments and extending our expected cash run way to fund planned operations into the middle of 2021.Now, turning to Slide 6, I'll take a moment to review the XPOVIO product profile and approved designation.

XPOVIO was approved in combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma which disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody.XPOVIO is the first and only prescription medicine approved in the U.S.

for this indication which encompasses a group of patients with a particularly poor prognosis and concentrating in acute unmet medical need.

Therefore, we believe that the approval of XPOVIO truly represents an advancement in the treating paradigm for patients battling highly refractory multiple myeloma.There is also important safety information included in the XPOVIO product label as shown on Slide 7.

This information includes important warnings and precautions related to the treatment with XPOVIO highlighted in the first bullet on this slide. Notably, there are no black box warnings or contraindications in the label.

And the patient medication guide has been included to educate patients on the expected side effect profile for XPOVIO.While Perry will provide some more detailed commentary about the early feedback we are hearing from physicians, I will note that the instruction makes XPOVIO label including the recommended supportive care guidelines and dosage modification criteria, appear to be easy for healthcare providers and patients [indiscernible].These recommendations are supported both by our field based medical science liaison reports as well as several commercial programs which will be discussed shortly.

Based on our early experience to-date, we remain highly confident physicians and other healthcare providers are well positioned and capable of effectively supporting patients while on XPOVIO therapy.

Complete treatment [ph] guidelines, along with the complete prescribing information can be found at www.xpovio.com.And with that, I'll now turn the call over to Perry, who will begin on Slide 9..

Thank you, Michael, and as you've indicated earlier, I am pleased to report that the XPOVIO launch is off to a terrific start.

As a reminder, to help support the commercial launch, we have deployed more than 70 sales representatives and nurse liaisons to educate the healthcare professional community about XPOVIO, each with extensive pharmaceutical, hematologic oncology and a multiple myeloma experience.These commercial efforts are also being supported by an experienced account management team that interacts with payers and our distribution partners, as well as our comprehensive, fully integrated carry forward support program for patients, caregivers, and healthcare providers.Based on analysis of Symphony claims data, we estimate that about 1300 accounts generate roughly 80% of all multiple myeloma prescription in the U.S.

and as you might expect, we are placing an emphasis in these early days on the 400 highest volume accounts which are generating roughly half of all myeloma prescriptions.Turning now to Slide 10, there are several components of our overarching commercial launch strategy which we believe have been integral to our early success.

They include, establishing nuclear export inhibition as a novel, fundamental approach in the treatment of multiple myeloma, positioning XPOVIO as the oral agent of choice with a clinically meaningful efficacy profile in its approved indication, educating healthcare providers and patients on XPOVIO’s side effect profile and related management strategies, and finally, minimizing access barriers to help appropriate patients start and stay on therapy.

These core tenets are the foundation of the ongoing rollout and what we believe have led to such a strong start for XPOVIO in the first few months on the market.On Slide 11, I will highlight some key metrics that provide a bit more detail on our early commercial achievements.

As of September 30, 2019 there were over 300 unique XPOVIO prescribers and prescribing accounts, including over 100 prescribers who have already begun XPOVIO treatment in multiple patients.

In total, we saw over 500 XPOVIO prescriptions generated and fulfilled by the end of September.I am also excited to report that XPOVIO prescriptions and patient demand increased each month following approval, from July to August and then from August to September.

Sales were driven by a combination of new patient starts, prescription refills and initial inventory to Karyopharm's distribution partners.Of course, as excited as we are, this early rapid adoption, it is still too early in the long cycle to say with much certainty if sales were positively impacted by an initial bolus of patients in these first few months.

While we do believe there were many patients eagerly awaiting XPOVIO's approval, we will still need to track additional months of prescription data to have a better sense of the expected future sales trajectory.In addition, despite the availability of a number of excellent drugs for patients with multiple myeloma, essentially all patients will develop disease that is refractory to the previously approved agents and thus many will become candidates for XPOVIO.

We look forward to continuing to educate the healthcare community on XPOVIO as a consensual [ph] treatment option for patients with heavily pretreated multiple myeloma.Let me now also highlight a few sales force metrics that we're particularly proud of and that we believe played a key role in our successful first few months.

First, as of September 30, 97% of the top 200 myeloma prescribing physician accounts have been seen by a Karyopharm representative.

We think this is a testament to both our focused selling strategy as well as the high level of interest from the myeloma community in learning about XPOVIO and its novel mechanism of action.Next, XPOVIO was ranked number two in IQVIA's BrandImpact survey for July and August which tracks the share of pharmaceutical sales calls to oncologists for a multiple myeloma drug second only to [indiscernible].

This is a tremendous accomplishment for a brand-new commercial player in the cancer space and again reinforces our belief that we have the right people in place and the right resources dedicated to effectively promoting XPOVIO.Turning now to Slide 12, we also believe that a key contributor to our early success has been driven by our ability to quickly secure reimbursement coverage for XPOVIO.

Our team has made tremendous progress during the first 90 days of the launch resulting in XPOVIO being added to a number of key National Pharmacy Benefit Manager Formularies and National Insurers Coverage Policies.Based on prescription fulfillment data through the specialty pharmacy channel, we estimate that approximately 60% of XPOVIO prescriptions have been dispensed to patient with Medicare coverage, 35% to patients with commercial insurance, and the remaining 5% of the patients having either Medicaid or another form of prescription coverage.

Today, we have fortunately experienced few reimbursement challenges and we believe insurers understand that patients with heavily pretreated multiple myeloma have a very high level of unmet medical need.The recent addition of XPOVIO to the National Comprehensive Cancer Network or NCCN Myeloma Guidelines and the publication of the STORM study results in the New England Journal of Medicine have also been well-received by payers and contributed to the positive discussions with the payer community.Let me also provide some final commentary on the early feedback we are hearing from prescribing physicians which you can see on Slide 13.

Most physicians which whom we have interacted with indicate that the clinical efficacy reported in the STORM study is highly compelling and the patient responses reported in the post approval setting are consistent with the clinical experience seen in STORM.Further, while the data is still early, patient prescription refills have been steadily increasing each month since the launch with some patients already receiving a third monthly prescription of XPOVIO which is quite encouraging.

With respect to tolerability, proactive education about prevention and management of potential side effects is being well received by both physicians and nursing staffs.

Importantly, a low rate of patient discontinuations due to side effects has been observed to-date.Finally, the 160 mg dose which is taken as 80 mg twice a week is the most frequently prescribed dose for both new patients and prescription refills, further validating our belief that most physicians are able to support their patient's and help mitigate or manage side effects of XPOVIO at the recommended starting dose.In summary, while it is still early days and we have a lot of work in front of us, we are extremely proud of the commercial launch thus far.

We are pleased with the overall feedback and insights coming from early prescribers and we believe there is still significant untapped opportunity for greater utilization.In the upcoming months and quarters ahead, we anticipate seeing a greater number of high-volume myeloma accounts writing their first prescription, a greater number of repeat prescriptions coming from those already prescribing and increased penetration and utilization from mid volume myeloma prescribing accounts.I'll now turn the call over to Mike Mason to review the financials..

Thank you, Perry. Since we issued a press release earlier today with the full financial results, I will just focus on the highlights.

As shown on Slide 15, for the third quarter of 2019, net product sales were $12.8 million which reflect the first quarter of recorded sales for XPOVIO.As previously mentioned, these sales were driven by a combination of patient demand, as well as initial channel inventories sold via our distribution partners.

We estimate that of the $12.8 million in quarterly sales, approximately $10 million was driven by patient demand with the remaining approximately $3 million driven by channel inventory.The estimated gross to net discounts for XPOVIO in the third quarter was approximately 15%, which is on the lower end of our annual expectation of 15% to 20%.

We still project a steady state range of 15% to 20%. However, we do expect some variability from quarter to quarter.Cost of sales in the third quarter of 2019 was $1 million which reflects the cost of XPOVIO units sold and third party royalties on our net product revenue.

For the third quarter of 2019 R&D expense was $26.3 million compared to $36.4 million for the third quarter of 2018. This reduction in costs is reflective of our financial discipline and commitment to focusing on our most critical and promising R&D activities.

We expect R&D expense to be relatively consistent for the final quarter of 2019 compared to the third quarter of 2019.SG&A expense for the third quarter of 2019 was $25.3 million compared to $13 million for the third quarter of 2018.

The increase in SG&A expenses compared to the prior-year period was due primarily to related commercial launch activities supporting the U.S. commercial launch of XPOVIO.We expect SG&A expenses for the fourth quarter of 2019 to be relatively consistent with Q3.

For the third quarter of 2019 we reported a net loss of $41.4 million or $0.67 per share compared to a net loss of $48.1 million or $0.79 per share for the third quarter of 2018.

Net loss includes stock-based compensation expense of $3.7 million and $4.8 million for the third quarters of 2019 and 2018 respectively.Turning now to Slide 16, I will highlight the improvements we have made on our balance sheet and some guidance for the future.

In September 2019, Karyopharm executed a Royalty Agreement with HealthCare Royalty Partners, of up $250 million to support the ongoing development and commercialization of XPOVIO.Under the terms of the agreement, we received $75 million in September, 2019 and are eligible to receive an additional $75 million with the agreement of both parties and upon the achievement of future regulatory and commercial milestones.

In exchange for the first $75 million, HCR will receive a tiered royalty in the mid single digits based on worldwide net revenues of XPOVIO and any other future products beginning in October 2019.As of September 30, 2019 cash, cash equivalents and investments, including restricted cash totaled $270.3 million compared to $330.9 million as of December 31, 2018.

Finally based on our current operating plan we expect our full year 2019 non-GAAP operating expenses, which excludes stock-based compensation to be between $200 million to $210 million as compared to our previous guidance of $200 million to $215 million.

We now expect that our existing cash, cash equivalents and investments, based on our current operating plan will be sufficient to fund planned operations, into the middle of 2021.I'll now turn the call back over to Michael for some concluding remarks.

Michael?.

Thank you, Mike. Before moving to the Q&A, let me reiterate that our overarching goal remains to develop novel medicines for patients with cancer and other serious diseases and we see the successful STORM study and accelerated approval of XPOVIO as a giant leap forward towards that goal.

But it is the first in what we hope to be many future successful trials and approvals across many indications.Now, I'll provide a quick review of our key upcoming milestones found on Slide 17. First, we will continue to execute on our commercial launch initiatives for XPOVIO in the U.S.

and look forward to providing you with future updates on our progress. For the pivotal Phase 3 BOSTON study top line data are expected in early 2020 depending on the occurrence of progression events in the trial.

If positive, these data could support regulatory submissions in 2020 in second-line myeloma.For our next potential indication in relapsed or refractory DLBCL, we expect to submit an NDA to the FDA with a request for Accelerated Approval based on the sale and trial results by the end of 2019 and MEA in Europe in 2020.

Next, we continue to work closely with the EMA in support of our MAA requesting a conditional approval for selinexor and we expect to receive a decision in early 2020.And finally, we expect to progress our late-stage solid tumor programs and look forward to potential additional regulatory filings and commercial launches in the future.

In summary, the XPOVIO commercial launch is off to a very strong start, and we are highly encouraged by the early commercial uptake and positive feedback from prescribing physicians.As we look ahead to the next few months and into 2020, we have a number of value creating milestones on the horizon, all of which have the potential to be transformative, both for Karyopharm and for patients battling multiple myeloma, DLBCL and potentially other cancers in the near future.I'll now turn the call over to the operator for questions..

[Operator Instructions] And our first question comes from the line of Brian Abrahams with RBC Capital Markets. Your line is now open..

Hi guys. Thanks very much for taking my questions and congrats on the strong start to the launch. A few from me, I guess, first off, you described some of the refill rates that you're seeing.

And I'm curious what your sense is on how that might - those might translate to overall compliance rates long-term, and then overall duration of use and how you think duration is going to evolve in this population?.

Yes, while it's still too early to know with accuracy what the refill rate has been, as many patients are still early in their initial treatment, we do know that for a significant percentage of our sales, which were ordered by cancer clinics through specialty distributors, such as [indiscernible] McKesson, we don't have access to that patient level data, and we only see total prescriptions with no delineation between a new patient and a refill.So in some instances it is harder to gauge actually where we are with the refills.

But what we do know is that the patients that were first prescribed with XPOVIO in that first month post approval, we've already seen some patients receive their third monthly prescription.And what I can tell you in general, we're not hearing from customers or seeing data from our specialty pharmacy providers, that a high number of patients are discontinuing therapy due to side effects.

In fact, we're hearing from a number of physicians, especially those who use proactive supportive care, which is outlined in our full prescribing information for XPOVIO and a big part of our commercial education efforts that these physicians are seeing fewer than expected discontinuations due to side effects.So as this continues, we would anticipate, A) If they have a better experience that we're going to get more refills.

It's also going to – they'll probably look to add more patients on therapy because of the good success that they are having. So we would anticipate that those refill rates will continue..

Got it. And then you talked about month-over-month growth within the third quarter.

I'm curious if you could give us any more color around that? And I guess, what metrics you might be looking for within those particular monthly trends that might help guide the degree of pent up demand that influenced the early launch? And then I have one more quick follow-up on BOSTON..

Yes, this is Ian. I'm not sure, again, as Perry mentioned, the data is certainly in the early days. And so I think at this stage, there's not more detail that we can provide about those refill rates and those trends other than, we continue to be very pleased with the trajectory of that launch right now..

Understood, I realize it's very early days. And then lastly, it looks like you refined the timeline for when you might expect to see the BOSTON readout.

Just wondering, anything that sort of influenced the narrowing of that timelines there, and maybe how quickly we might think about when we would see a sales inflection post BOSTON if the data are positive? I guess I'm curious in terms of how quickly a filing could be turned over with the FDA, how quickly there could be an NCCN submission, any sense you're getting from payers as to how quickly they might provide reimbursement for an earlier line population? Thanks..

Yes, well, first on the easy part, which is the -- this trial is event driven.

So we're waiting on events and as you all know, that towards the tail end of any myeloma trials, driven by primarily patients who have complete responses and very good partials, and so we're really waiting for relapses in mainly those patients.So it's - the refinement and the timeline is simply reflective of where we are in the number of events and where we believe we need to be for the trial to readout.

We are not going to comment today on what would happen subsequently. You can be rest assured, however, that the Company is really singularly focused on turning around BOSTON as expeditiously as possible with quality data that have all been, you know, IRC reviewed, DSMV reviewed and so on.

And communicating with FDA urgently, because we recognize the urgent medical need for these patients with myeloma. So we're moving as quickly as we can, Brian..

Got it. Thanks so much, guys and congrats again on the launch..

Thank you. And our next question comes from the line of Eric Joseph with JPMorgan. Your line is now open..

Hey guys, let me also add my congrats on the early launch progress, and thanks for taking the questions.

I guess as it relates to insurance coverage at this point, can you just comment on the extent of any outstanding or ongoing reviews that might still kind of present as a barrier to reimbursement at this point? And to the extent there has been any pushback amongst payers, can you just provide some color around that point? Thanks..

Yes, so I appreciate the question. So far, the response from the payers has been generally positive. We're not encountering significant roadblocks there.

Still early in the launch cycle, but we do get the sense that the payers understand the urgency with which these patients need additional therapies.We're seeing prescriptions generated and subsequently approved from both large commercial payers and Medicare Part D plans.

In terms of the time it's taking, you know, our goal is of course to get this as short as possible and we've seen progress with that every single month since launch.The approval time for the payers has been progressing and we want to get that down to less than a week and sometimes that's already happening.

So we continue to work hard with the payer community so that the review timeline is short. And honestly, we're not seeing any significant roadblocks. And we've had, actually, no denials within our approved indications to date..

Great. And maybe just a follow-up point on, as it relates to AE related discontinuations. Can you just point, sort of quantify what low means and whether there's any common trends driving patient discontinuations? Thanks..

Yes.

So I - when we look at discontinuations, a lot of this feedback from physicians and what we see through our specialty pharmacy network and when we talk about it being low, it's within the range of what we saw in the STORM trial, and lower than what we actually would have anticipated based upon the results of that trial.And our team is definitely working hard with the accounts on the proper supportive care protocols, and what we've seen is those accounts that put the right supportive care programs in place, are having very few discontinuations due to adverse events..

Yes, and we - we can't really quantify, just to add on to Perry. But through our pharmacovigilance, post-marketing pharmacovigilance, we see largely the same kinds of side effects. What appear to be at lower rates and what we're reporting in STORM, part of that's because post-marketing things tend to be reported lower.

But stopping the drug due to side effects seems to be lower than what was in the clinical trial..

Thank you. And our next question comes from the line of Jonathan Chang with SVB Leerink. Your line is now open..

Hi, guys. Thanks for taking my questions and congrats on the strong launch. First question, in the past, you've spoken about your view that demand for XPOVIO could be strong in the community settings.

Any color on the dynamic between the academic community settings and any difference in physician feedback there? I guess, specifically, what has the early feedback been with regards to the management of adverse events?.

Yes. So we've seen a very good mix of demand coming from both commercial and academic. I know that there was some talk about the drug in the community based setting and we see very positive feedback from the community based setting. And they seem to be putting patients on at the appropriate dose and the patients have been able to stay on that dose..

Got it.

And one other question from me, has the second interim for the BOSTON study occurred? And if the second interim passed is this something you guys would disclose?.

Thanks. We're not prepared to discuss any of that, just simply to say that we anticipate top line data in the first quarter next year. And we'll disclose what we can at that time and then at a future medical meeting..

Got it. Thanks for taking my questions..

Thank you. And our next question comes from the line of Maury Raycroft with Jefferies. Your line is now open..

Hey everyone, good morning. Congrats on the progress and thank you for taking my questions.

First question is just, if you can comment on whether the patients treated so far reflect the label or are you getting some earlier line us from centers or doctors that are familiar with the drug? And if there's any use that's not specifically in the label, can you talk about how the reimbursement process has been for those patients?.

Yes. So our commercial team, of course, can and will only promote XPOVIO based on its FDA approved indication. Some physicians may choose to combine XPOVIO with other anti-myeloma drugs, which is generally how myeloma patients are treated. But we do not systematically have access to these kinds of metrics.

Our medical affairs team does get unsolicited requests for clinical information about combination studies with XPOVIO and other standard anti-myeloma drugs. With regards to the payer community, I can't comment on really what they're doing with regards to any XPOVIO legalization [ph]..

Got it. That's helpful.

And just as a follow-up, just wondering if you can provide any additional perspective on the supportive care strategies to keep patients on therapy? I guess, how useful have the doctor management strategies been versus carry forward support and how are those two working together? And then what other variables can be tweaked to help keep patients on therapy?.

Yes, so we have to take a three-pronged approach to this. We work with our specialty pharmacy providers in carry forward to work with the patients to ensure that they have the proper supportive care medications on board when they start therapy.

And then our team of sales representatives and specifically our Karyopharm nurse liaison team, work with the accounts to talk with the prescribers about the proper supportive care profile and the supportive care measures that are necessary to ensure patient success.Also our dose and dose modification guide within our packages are really spells things out appropriately for prescribers.

So we're able to kind of wrap that patient and the office with the right care that they need to ensure patient success..

Got it. Thank you very much..

Thank you. And our next question comes from the line of Arlinda Lee with Canaccord. Your line is now open..

Hi, this is Catherine on for Arlinda. Congrats on the launch progress. Just a few questions this morning.

First, can you give some insight into how filling the initial channel inventory affected revenue this quarter? And how should this influence how we look at revenue trends going forward?.

Yes, so the $12.8 million of net revenue for the quarter, about $10 million of it was demand revenue to patients, about $2.8 million was for channel inventory.

And I think it's too early to comment on revenue trend going forward.But certainly, the channel we try to - we manage it with our -- specialty pharmaceuticals, specialty distributors, for which they keep around three to four weeks of inventory on hand..

Oh okay, thanks. And my second question is with regards to the SADAL results. So the NDA is for third line CAR-T and stem cell transplant eligible.

Can you speak to the response rate PFS and DOR [ph] in this specific subset of patients from the trial?.

Sure. The data, yes, basically what was presented at the ICML oral presentation this past year. The response rate was in the 28% range. These are all, by the way, independent adjudicated radiological responses. And the duration of response was 9.3 months for the group.

And I should also point out that amongst the responders, the 28%, approximately 11% had complete remissions.The PFS was not - is not a variable that FDA recognizes in the setting of an accelerated approval, because it's a single arm trial..

Okay. Thank you very much. Could you also comment on what FDA has seen in the BOSTON trial when you got the accelerated approval? Thanks..

Sure. FDA chose to give a little more structure to what they had looked at as BOSTON is part of the STORM study. And they had seen all of the safety data, which of course, we are privy to, including the number of deaths on each arm of the study.

And as we've said, there's absolutely no imbalance of death against XPOVIO on the BOSTON study and that continues till today.They also saw efficacy data which we are not privy to, including response rate and early progression events. This was the first interim analysis that was reviewed by the DSMV.

And we should also point out that that did not result in any change in the trial. So presumably, what we're seeing was on target for the design of the study, which was to show a hazard ratio of 0.7 or better..

Thank you. And our next question comes from the line of Mike Ulz with Baird. Your line is now open..

Hi, guys, thanks for taking the question and congratulations as well on the strong launch year. Just now you are months into the XPOVIO launch in the U.S.

Are you still comfortable with the size of your sales force, which I think is around 70 sales reps?And then secondly, assuming the BOSTON study is positive here, how are you thinking about the size of the sales force next year? And then I have a quick follow-up..

So with regards to the size of the team, currently, absolutely, we're very comfortable with the size of the team that we have. And I think that's been validated by some of the research that we've seen.

I mentioned before the IQVIA BrandImpact Survey, which we were #2 in myeloma.And then even with the BOSTON approval, ultimately, that does not change the size of your customer base. And we have great reach to our customers right now. So we're quite comfortable with where we stand with BOSTON as well..

Got it. Thanks for that. And then maybe if you can just comment on any updates related to your filing of XPOVIO in Europe. Looks like in the queue, there are a couple updates there. Thanks..

I think, I always say is that the timing of the expected decision is in the early part of 2020. And this is based on normal interactions between us and the EMA aperture, cover aperture and the other regulators..

Great, thanks..

Thank you. And our last question comes from the line of Ed White with H.C. Wainwright. Your line is now open..

Hi, guys, thanks for taking my questions and congratulations on the revenue number.

So just to follow-up on that last question for Europe, maybe you can discuss your strategy or when you will be able to discuss the strategy with us for European launch?.

Yes, sure. Hey, this is Chris. So, we continue to assess numerous options for potential commercialization in Europe. The key is for us are maximizing access for patients and value for Karyopharm. So to that end, one option could include a partnership.

In this scenario, we look for a partner that is in a partnership that's mutually beneficial for both parties and maximize the potential of selinexor in the European market.Importantly, we'd be looking for a partner who aligns with our philosophy regarding long-term development and commercialization plans for selinexor, and has expertise and the infrastructure in marketing hematological malignancy drugs.A second option on the other end of the spectrum could be to potentially launch selinexor on our own in select European countries where reimbursement negotiations and decisions typically occur more quickly and at acceptable levels.So from our perspective, we believe the value of selinexor will build over time, particularly as we progress through the regulatory process in multiple myeloma, and as we submit our NDA and MAA and [indiscernible] based on our results SADAL study in a way BOSTON data early next year..

Okay, great. Thanks for taking my question..

Thank you. And this concludes today's question-and-answer session. I would now like to turn the call back to Michael Kauffman, CEO, for any closing remarks..

Thank you, everybody, for joining us today. Exciting times and have a great day. Talk soon..

Ladies and gentlemen, this concludes today's conference call. Thank you for participating. You may now disconnect..