Viracta Therapeutics, Inc. (Nasdaq: VIRX), a clinical-stage
precision oncology company focused on the treatment and prevention
of virus-associated cancers that impact patients worldwide, today
reported positive Phase 2 NAVAL-1 trial results from Stages 1 and 2
of the relapsed or refractory (R/R) Epstein-Barr virus-positive
(EBV+) peripheral T-cell lymphoma (PTCL) cohort. Additionally, the
Company received productive feedback from its meeting with the U.S.
Food and Drug Administration (FDA), providing clarity on the
potential regulatory path to initial registration of Nana-val in
patients with R/R EBV+ PTCL. Based on FDA’s feedback, Viracta plans
to begin a randomized controlled trial (RCT) of Nana-val in the
second half of 2025.
“We are pleased to present important additional data from our
NAVAL-1 trial, which further supports Nana-val’s potential to
address the high unmet medical needs of patients living with
relapsed or refractory EBV-positive PTCL,” said Darrel P. Cohen,
M.D., Ph.D., Chief Medical Officer of Viracta. “Nana-val
demonstrated substantial antitumor activity with a generally
well-tolerated safety profile across Stage 1 and Stage 2 of the
relapsed or refractory EBV-positive PTCL cohort, with a median
duration of response that has not yet been reached. We are also
encouraged by the particularly robust clinical responses observed
in the second-line EBV-positive PTCL subgroup.”
Mark Rothera, President and Chief Executive Officer of Viracta,
added, “Aligning with the FDA on the potential path forward in
relapsed or refractory EBV-positive PTCL marks a critical step
towards bringing Nana-val to patients. EBV-positive PTCL is an
aggressive cancer with survival rates that decline precipitously
12-24 months after diagnosis. Published literature suggests that
EBV-positive lymphomas are a distinct oncological disease
associated with poorer survival outcomes than EBV-negative
lymphomas. We believe it is critical to treat these patients as
early as possible with an EBV-targeted therapy to improve patient
outcomes. Our updated Nana-val clinical development plan is
designed to address this urgent need and expedite a randomized
controlled trial, which we plan to initiate in 2025 to support
potential registration.”
Key Takeaways from the R/R
EBV+ PTCL Cohort of the Phase 2
NAVAL-1 TrialOverview: A total of 21 patients with
primarily Stage III-IV disease (who had received ≥1 [median 2]
prior systemic PTCL therapies) received nanatinostat (20 mg orally
once daily, 4 days/week) in combination with valganciclovir (900 mg
orally once daily, 7 days/week) across the first two stages of the
study. Data generated from the expansion phase of the R/R EBV+ PTCL
cohort may be shared in future updates.
As of the June 28, 2024 data cutoff, combined Stages 1 and 2
data demonstrated:
- In the R/R EBV+ PTCL population:
- The overall response rate (ORR) was 33% and the complete
response rate (CRR) was 19% in the intent-to-treat (ITT) population
(n=21); the ORR was 41% and the CRR was 24% in the
efficacy-evaluable (EE) population (n=17).
- In the second-line EBV+ PTCL subpopulation:
- The ORR was 60% and the CRR was 30% in the ITT population
(n=10); the ORR was 67% and the CRR was 33% in the EE population
(n=9).
- Median duration of response (DOR) has not yet been reached.
- Two responding patients proceeded to hematopoietic stem-cell
transplant without relapse, one of whom remains in response over 16
months.
- Nana-val was generally well-tolerated:
- The most common treatment-related adverse events were fatigue,
nausea, decreased appetite, diarrhea, platelet count decreased, and
anemia. These adverse events were primarily mild to moderate in
severity and generally manageable or reversible.
Nana-val Clinical Development Plan: Next
StepsBased on the Company’s meeting with FDA and the
particularly robust response rates observed in the second-line
treatment setting, Viracta will focus Nana-val’s clinical
development on patients with R/R EBV+ PTCL as follows: First, the
Company will focus the primary analysis on the second-line EBV+
PTCL subpopulation in the ongoing NAVAL-1 trial’s expansion phase.
Second, the Company plans to begin an RCT of Nana-val in the
second-line treatment of EBV+ PTCL patients in 2025. Viracta
believes this strategy will best position Nana-val for a potential
NDA filing in 2026 for accelerated approval based on an interim
analysis of second-line EBV+ PTCL patient data from the NAVAL-1
trial, provided that the ORR and DOR are compelling and the RCT is
well underway. In addition, it creates the opportunity for
accelerated approval based on final analysis of NAVAL-1 trial data,
or for accelerated or full approval based on the outcomes of the
RCT at interim or final analysis, respectively.
Corporate Update Viracta has aligned resources
to prioritize its EBV+ lymphoma program and plans to deliver on key
potential Nana-val development milestones as follows:
- Pause the EBV+ solid tumor program to focus resources on the
more advanced EBV+ lymphoma program.
- The recommended Phase 2 dose in patients with advanced EBV+
solid tumors is expected to be determined in the second half of
2024.
- Report additional data from the ongoing expansion phase of the
NAVAL-1 trial in second-line EBV+ PTCL patients in the fourth
quarter of 2024.
- Report Stage 1 data from patients with R/R EBV+ diffuse large
B-cell lymphoma (DLBCL) in the first half of 2025.
- Meet with the FDA to finalize the proposed RCT design in the
second-line treatment of patients with EBV+ PTCL in the first half
of 2025.
- Initiate the RCT in the second half of 2025.
- Present interim analysis outcomes from the expansion phase of
the NAVAL-1 trial in second-line EBV+ PTCL patients in 2026.
- File NDA for accelerated approval in 2026 based on interim
analysis of the NAVAL-1 trial’s expansion cohort.
Along with this pipeline reprioritization, a reduction in force
has been implemented that impacts approximately 23% of the
Company’s employees.
Conference CallViracta will host an investor
call on Wednesday, August 14 at 8:30 a.m. ET to discuss the
positive Phase 2 NAVAL-1 trial results from Stages 1 and 2 of the
R/R EBV+ PTCL cohort. A live question and answer session will
follow the formal presentation. To register, click here.
About the NAVAL-1 TrialNAVAL-1 (NCT05011058) is
a global, multicenter, clinical trial of Nana-val in patients with
relapsed or refractory (R/R) Epstein-Barr virus-positive (EBV+)
lymphoma. This trial employs a Simon two-stage design where, in
Stage 1, participants are enrolled into one of three indication
cohorts based on EBV+ lymphoma subtype. If two objective responses
are achieved within a lymphoma subtype in Stage 1 (n=10), then
additional patients will be enrolled in Stage 2 for a total of 21
patients. EBV+ lymphoma subtypes demonstrating promising antitumor
activity in Stage 2 may be further expanded following discussion
with regulators to potentially support registration.
About Nana-val (Nanatinostat and
Valganciclovir)Nanatinostat is an orally available histone
deacetylase (HDAC) inhibitor being developed by Viracta.
Nanatinostat is selective for specific isoforms of Class I HDACs,
which are key to inducing viral genes that are epigenetically
silenced in Epstein-Barr virus (EBV)-associated malignancies.
Nanatinostat is currently being investigated in combination with
the antiviral agent valganciclovir as an all-oral combination
therapy, Nana-val, in various subtypes of EBV-associated
malignancies. Ongoing trials include a potentially registrational,
global, multicenter, open-label Phase 2 basket trial in multiple
subtypes of relapsed or refractory (R/R) EBV+ lymphoma (NAVAL-1) as
well as a multinational Phase 1b/2 clinical trial in patients with
recurrent or metastatic (R/M) EBV+ NPC and other advanced EBV+
solid tumors.
About Peripheral T-Cell LymphomaT-cell
lymphomas comprise a heterogeneous group of rare and aggressive
malignancies, including peripheral T-cell lymphoma not otherwise
specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL).
There are approximately 5,600 newly diagnosed T-cell lymphoma
patients and approximately 2,600 newly diagnosed PTCL-NOS and AITL
patients in the U.S. annually. Approximately 70% of these patients
are either refractory to first-line therapy, or eventually
experience relapse of their disease. Clinical trials are currently
recommended for all lines of PTCL therapy, and most patients with
R/R PTCL have poor outcomes, with median progression-free survival
and median overall survival times reported to be 3.7 and 6.5
months, respectively. Approximately 40% to 65% of PTCL is
associated with EBV, the incidence of EBV+ PTCL varies by
geography, and reported outcomes for patients with EBV+ PTCL are
inferior to those whose disease is EBV-negative. There is no
approved targeted treatment specific for EBV+ PTCL, and therefore
this represents a high unmet medical need.
About EBV-Associated CancersApproximately 90%
of the world's adult population is infected with EBV. Infections
are commonly asymptomatic or associated with mononucleosis.
Following infection, the virus remains latent in a small subset of
cells for the duration of the patient's life. Cells containing
latent virus are increasingly susceptible to malignant
transformation. Patients who are immunocompromised are at an
increased risk of developing EBV-positive (EBV+) lymphomas. EBV is
estimated to be associated with approximately 2% of the global
cancer burden including lymphoma, nasopharyngeal carcinoma (NPC),
and gastric cancer.
About Viracta Therapeutics, Inc.Viracta is a
clinical-stage precision oncology company focused on the treatment
and prevention of virus-associated cancers that impact patients
worldwide. Viracta’s lead product candidate is an all-oral
combination therapy of its proprietary investigational drug,
nanatinostat, and the antiviral agent valganciclovir (collectively
referred to as Nana-val). Nana-val is currently being evaluated in
multiple ongoing clinical trials, including a potentially
registrational, global, multicenter, open-label Phase 2 basket
trial for the treatment of multiple subtypes of relapsed or
refractory (R/R) Epstein-Barr virus-positive (EBV+) lymphoma
(NAVAL-1), as well as a multinational, open-label Phase 1b/2
clinical trial for the treatment of patients with recurrent or
metastatic (R/M) EBV+ nasopharyngeal carcinoma (NPC) and other
advanced EBV+ solid tumors. Viracta is also pursuing the
application of its “Kick and Kill” approach in other virus-related
cancers.
For additional information, please visit www.viracta.com.
Forward-Looking StatementsThis communication
contains "forward-looking" statements within the meaning of the
Private Securities Litigation Reform Act of 1995, including,
without limitation, statements regarding: the details, timeline and
expected progress for Viracta's ongoing and anticipated clinical
trials and updates regarding the same, Viracta’s clinical focus and
strategy, the Company’s expectations related to the FDA submission
process and timelines, expectations regarding the Company’s target
patient populations, and expectations regarding the Company’s cash
runway. Risks and uncertainties related to Viracta that may cause
actual results to differ materially from those expressed or implied
in any forward-looking statement include, but are not limited to:
Viracta's ability to successfully enroll patients in and complete
its ongoing and planned clinical trials; Viracta's plans to develop
and commercialize its product candidates, including all oral
combinations of nanatinostat and valganciclovir; the timing of
initiation of Viracta's planned clinical trials; the timing of the
availability of data from Viracta's clinical trials; previous
preclinical and clinical results may not be predictive of future
clinical results; the timing of any planned investigational new
drug application or new drug application; Viracta's plans to
research, develop, and commercialize its current and future product
candidates and the clinical utility, potential benefits, and market
acceptance of Viracta's product candidates; Viracta's ability to
manufacture or supply nanatinostat and valganciclovir for clinical
testing.
If any of these risks materialize or underlying assumptions
prove incorrect, actual results could differ materially from the
results implied by these forward-looking statements. Additional
risks and uncertainties that could cause actual outcomes and
results to differ materially from those contemplated by the
forward-looking statements are included under the caption "Risk
Factors" and elsewhere in Viracta's reports and other documents
that Viracta has filed, or will file, with the SEC from time to
time and available at www.sec.gov.
The forward-looking statements included in this communication
are made only as of the date hereof. Viracta assumes no obligation
and does not intend to update these forward-looking statements,
except as required by law or applicable regulation.
Investor Relations Contact:Michael FaermChief
Financial OfficerViracta Therapeutics, Inc.ir@viracta.com
SOURCE Viracta Therapeutics, Inc.
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