Full Press Release Details
C O R P O R A T E P A R T I
Allison Soss, Investor Relations, KCSA
Strategic Communications
Angelos Stergiou, MD, ScD hc, Founder,
President & Chief Executive Officer, SELLAS Life Sciences Group
M. Yair Levy, MD, Director of Hematologic
Malignancies, Baylor University Medical Center
Dragan Cicic, M.D. - Senior Vice President,
Clinical Development, SELLAS Life Sciences
P R E S E N T A T I O N
Hello and thank you for standing by. Welcome to
the SELLAS Life Science REGAL Update Conference Call and Webcast. At this time all participants are in a listen-only mode.
As a reminder, this conference is being recorded.
It's now my pleasure to introduce your host,
Allison Soss, Investor Relations. Please go ahead.
Good morning everyone. The focus of today's call
is SELLAS's Phase 3 clinical trial of GPS in patients with acute myeloid leukemia in second remission, the REGAL study.
Dr. Angelos Stergiou, the Company's President
and Chief Executive Officer, will begin today's call with some important updates regarding REGAL and then introduce our additional speaker,
Dr. Yair Levy of Baylor University Medical Center, as well as Dr. Dragan Cicic, SELLAS's SVP of Clinical Development who will participate
Following the presentations, we will hold a Q&A
session. As we will likely not have time to answer every question, we will give priority to questions from the Company's covering
analysts. We kindly ask the covering analysts to submit your questions at any time during today's program using the Q&A prompt in
the webinar. We will hold all questions until the dedicated Q&A session where the team will answer as many as they can in the time
permitted. We kindly ask that your questions be addressed only to the subject matter of today's call.
Before we begin, I would like to remind you
that SELLAS will be making statements on today's call relating to future expectations regarding the further development of and
regulatory plans for GPS. These statements constitute forward-looking statements for purposes of Safe Harbor provisions under the
Private Securities Litigation Reform Act of 1995 and by their nature involve estimates, projections, goals, forecasts and
assumptions and are subject to risks and uncertainties, which include, without limitation, risks and uncertainties associated with
the COVID-19 pandemic and its impact on the Company's clinical plans, risks and uncertainties associated with immunotherapy product
development and clinical success thereof, the uncertainty of regulatory approval and other risks and uncertainties affecting SELLAS
and its development programs that could cause actual results or outcomes to differ materially from those expressed in the
forward-looking statements. These forward-looking statements speak only as of the date of this conference call and should not be
relied upon as predictions of future events. While SELLAS may elect to update these forward-looking statements at some point in the
future, the Company disclaims any obligation to do so, even if the Company's views change.
ViaVid has made considerable efforts to provide an accurate transcription. There may be material errors, omissions, or inaccuracies in
the reporting of the substance of the conference call. This transcript is being made available for information purposes only.
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Additional information about the material factors
and assumptions forming the basis of forward-looking statements and risk factors can be found under the caption Risk Factors in SELLAS'
Annual Report on Form 10-K filed on March 31, 2022, and in its other SEC filings.
With that, I would like to turn the call over
to Dr. Angelos Stergiou, SELLAS' President and CEO.
Good morning everyone and welcome to our REGAL
update call. First, thank you for your participation and support in joining us today and, as I've repeatedly stated, when we have meaningful
updates we will hold such calls and today is such an occasion. We are very excited to take this time today to focus on some important
developments regarding the GPS Phase 3 REGAL study. It is my pleasure to also be joined by Dr. Yair Levy, whom I will introduce shortly,
as well as our Senior Vice President of Clinical Development Dr. Dragan Cicic.
At SELLAS, we believe that GPS has the potential
to change the face of treatment for leukemia and other WT1 expressing tumors, such as ovarian cancer. We believe that GPS has the potential
not only to help cancer patients in remission to live significantly longer, but also to provide treatments to patients and the opportunity
for a more tolerable continuous treatment.
GPS is a highly differentiated immunotherapeutic
that has shown real clinical benefit in extending the lives of AML patients in remission, a growing unmet medical need, as well as in
The Phase 3 REGAL trial is designed to provide
reliable evidence about the effects of GPS maintenance monotherapy for its key primary endpoint of overall survival. In this study, patients
are randomized to receive either GPS treatment or best available treatment, or BAT. In our previous Phase 2 study in this exact AML CR2
patient population as our Phase 3 trial, we observed a clinically and statistically significant survival benefit in patients who received
GPS, an almost 16-month differential survival benefit-21 months versus 5.4 months-with a p-value of 0.02, and a substantial
difference in leukemia-free survival.
Our ongoing Phase 3 REGAL study has world-class
experts monitoring its progress. Although REGAL has an open-label design, to protect the integrity of randomization and as well as enable
the potential for refinements in study design during its conduct, based on emerging aggregate study data, SELLAS as the study sponsor
remains blinded to any data by treatment arm, ie. GPS versus BAT. However, we do have access to information about the event rate, which
is the accumulation of deaths over time in the entire study population enrolled to-date on a pooled basis; that is, the entire data set
combining patients in both study arms, GPS and BAT.
This pooled data set of the event rate has been
reviewed by SELLAS and our biostatisticians on a blinded basis, as this assessment of the estimated study duration allows for the adjustment
or refinement of our statistical analysis plan, or SAP. Recent review of the pooled data for the entire enrolled study population to date
in our REGAL study, while still being fully blinded as to patient allocation per arm, suggests that the median overall survival in the
pooled study population is likely considerably longer by a factor of 2X than the initial estimates upon which all initial statistical
assumptions were based.
ViaVid has made considerable efforts to provide an accurate transcription. There may be material errors, omissions, or inaccuracies in
the reporting of the substance of the conference call. This transcript is being made available for information purposes only.
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I do not want to speculate as to why or which
patients are living longer as this could be attributed to many factors, including the potential for and the extent of increased clinical
benefit reported by the active GPS arm as we have seen in our earlier Phase II study in the same AML CR2 patient population, as well as
treatment landscape and potentially better care for the patients participating in our study receiving GPS or BAT. Without unblinding the
study, it is currently impossible to confirm or refute any of these possibilities.
But the key understanding is that the initial
data from REGAL are suggestive that patients overall in the blinded pooled study population are collectively experiencing a longer than
originally expected overall survival duration. Please recall that there is nothing approved in the CR2 maintenance phase and the best
available therapy options have not proven to be effective in extending survival.
We have endeavored, with the assistance of our
biostatistics and clinical experts and other folks, who are highly respected and experienced, to consider an appropriate change in the
SAP for the REGAL study, given what we have learned from this review of the pooled data. The revised SAP and appropriately modified study
protocol were submitted to the FDA 31 days ago, on October the 14th. Please bear with me while I explain some more technical statistical
matters which are important for understanding why we have changed the SAP.
In summary, the key four points of our refinements
are: first, the targeted number of events or deaths for the interim analysis will be reduced to 60 from 80, and is expected to occur sometime
in late '23 or early '24. Second, the targeted number of events or deaths for the final analysis will be reduced to 80 from 105. Third,
the total targeted enrollment in the study will go from 116 patients to a range of 125 to no more than 140 patients, since the targeted
number of deaths would likely occur sooner in calendar time when the sample size of the trial is slightly increased. For example, under
assumed rates of enrollment by increasing trial sample size to 140 patients, the 80th death event would potentially occur approximately
three to four months sooner versus if we enrolled around 125 patients, and would also support China regulatory matters, which I will discuss
shortly. Lastly, statistical significance would be achieved by an estimated hazard ratio for overall survival of 0.636, corresponding
to an overall survival, for example, of 12.6 versus 8 months for GPS versus BAT, respectively.
In the original Statistical Analysis Plan-and