Preliminary data demonstrate FPI-2265 is
active in heavily pretreated patients with progressive metastatic
castration-resistant prostate cancer (mCRPC), including those who
received prior lutetium-based radioconjugates
HAMILTON, ON and BOSTON, April 9,
2024 /CNW/ -- Fusion Pharmaceuticals Inc.
(Nasdaq: FUSN), a clinical-stage oncology company focused on
developing next-generation radioconjugates (RCs) as precision
medicines, today announced the presentation of interim efficacy and
safety data from the Phase 2 TATCIST open-label clinical trial
evaluating FPI-2265, at the American Association for Cancer
Research (AACR) Annual Meeting 2024 being held April 5-10 in San
Diego, California. Results demonstrate that FPI-2265 is
active in heavily pretreated patients with progressive metastatic
castrate-resistant prostate cancer (mCRPC), including patients who
received prior lutetium-based RCs. Safety, tolerability and
clinical activity data were generally consistent with other
published studies of small molecule-based 225Ac-PSMA
RCs.
"The interim results from the TATCIST trial underscore the
potential of FPI-2265, the most advanced actinium-based prostate
specific membrane antigen (PSMA) targeted radiotherapy in
development, to improve treatment options for patients with mCRPC,"
said Fusion Chief Executive Officer John
Valliant, Ph.D. "We believe the interim results represent
compelling early clinical activity and tolerability data,
validating the path to develop FPI-2265 in patients who progress on
or after lutetium-based RCs. With our Phase 2 portion of the
registrational program for FPI-2265 expected to initiate in the
second quarter of 2024, and the expanding market for patients in
the post-PLUVICTO™ setting, we believe FPI-2265 has the potential
to meet the critical unmet needs of mCRPC patients."
The TATCIST trial is designed to evaluate patients with
progressive mCRPC, including patients who are naïve to
PSMA-targeted RCs and those who have been pre-treated with
177Lu-based PSMA RCs such as PLUVICTO™.
Phase 2 TATCIST Clinical Trial Interim Results
The results are being presented at the AACR 2024 Annual Meeting
in a poster presentation titled, "Preliminary efficacy and safety
results from the TATCIST trial: A PSMA-directed targeted alpha
therapy with FPI-2265 (225Ac-PSMA-I&T) for the
treatment of metastatic castration-resistant prostate cancer
(mCRPC)."
As of the March 1, 2024 data
cutoff, 35 patients received at least one dose of FPI-2265, with 25
patients having at least 12 weeks of follow-up. The analysis
included 25 patients for safety evaluation and 20 patients for
assessing prostate-specific antigen (PSA) response. Four
participants were identified as superscan patients and were
excluded from the efficacy analyses and reported separately in the
safety analysis. One participant was not included in the efficacy
analysis due to uninterpretable PSA response. Patients in the study
were pretreated with a median of four prior lines of anticancer
therapy, with 20 out of 25 (80%) receiving prior chemotherapy,
including 10 patients who received at least two prior lines of
taxanes. Nine out of 25 patients received a prior
177Lu-based PSMA RC.
From the efficacy-evaluable patient population, PSA50 (≥50%
decline in prostate-specific antigen by 12 weeks after first
treatment) response was achieved in 10 out of 20 patients (50%)
regardless of prior lutetium treatment. PSA50 was achieved in 61%
of lutetium-naïve participants and 42% of lutetium-treated
participants. In an exploratory subset analysis of 13 patients,
including six patients who received prior 177Lu-based
PSMA RC treatment, with baseline PSMA Mean Standardized Uptake
Value (SUVmean) >6, PSA50 response was observed in
nine patients (69%).
FPI-2265 demonstrated meaningful improvement in secondary
endpoints which include maximum % PSA decline, and independent
reviewer-assessed response rates based on RECIST v1.1 criteria, and
the rate of disease progression in bone per Prostate Cancer Working
Group 3 (PCWG3) criteria.
FPI-2265 was generally well tolerated and in line with prior
published data, with predominantly Grade 1-2 treatment-related
adverse events (TRAEs) observed, including xerostomia (dry mouth),
thrombocytopenia, anemia, fatigue and dry eye. Xerostomia, the most
common TRAE, was primarily Grade 1 with all incidences being Grade
1-2 (62% Grade 1 and 24% Grade 2). One treatment-related death due
to cerebral hemorrhage was reported in a superscan patient. Three
out of 25 participants discontinued treatment due to TRAEs,
including two participants in the superscan group, however there
were no discontinuations due to xerostomia.
These findings underscore the potential of FPI-2265 to provide a
viable therapeutic option for patients with progressive mCRPC,
including those who have previously undergone prior treatment with
lutetium-based RCs. Fusion will continue long term follow up in
patients evaluated in the TATCIST trial and now intends to
prioritize enrollment in the FPI-2265 Phase 2 portion of the
registrational program.
FPI-2265 Phase 2/3 Development Program in mCRPC
Fusion is advancing a Phase 2/3 trial for FPI-2265 in patients
with mCRPC with progressive disease who have previously been
treated with a 177Lu-based PSMA radiotherapy. The Phase
2 portion is expected to be initiated in the second quarter of
2024. A Phase 3 global registrational trial is expected to begin in
2025 following analysis of the Phase 2 data and an end of Phase 2
meeting to align with FDA on the recommended Phase 3 dosing
regimen.
A copy of the poster presentation can be found at:
https://fusionpharma.com/fusion-scientific-presentations/ following
the conclusion of the AACR Annual Meeting.
About FPI-2265
FPI-2265 is an actinium-225 based PSMA
targeting RC, for mCRPC, currently in a Phase 2 trial. Actinium-225
emits alpha particles and holds the promise of being a
next-generation radioisotope in cancer treatment. By delivering a
greater radiation dose over a shorter distance, alpha particles
such as actinium-225 have the potential for more potent cancer cell
killing, and targeted delivery, thereby minimizing damage to
surrounding healthy tissue.
About Fusion
Fusion Pharmaceuticals is a
clinical-stage oncology company focused on developing
next-generation RCs as precision medicines. Fusion connects alpha
particle emitting isotopes to various targeting molecules in order
to selectively deliver the alpha emitting payloads to tumors.
Fusion's clinical-stage development portfolio includes lead
program, FPI-2265, targeting PSMA for mCRPC and novel RCs targeting
solid tumors.
Forward-Looking Statements
This press release contains "forward-looking statements" for
purposes of the safe harbor provisions of The Private Securities
Litigation Reform Act of 1995, including but not limited to the
statements regarding the future business and financial performance
of Fusion Pharmaceuticals Inc. (the "Company"). For this purpose,
any statements contained herein that are not statements of
historical fact may be deemed forward-looking statements. Without
limiting the foregoing, the words "expect," "plans," "anticipates,"
"intends," "will," and similar expressions are also intended to
identify forward-looking statements, including any expressed or
implied statements regarding the successful development of
FPI-2265. Actual results may differ materially from those indicated
by such forward-looking statements as a result of risks and
uncertainties, including but not limited to the following: there
can be no guarantees that the Company will advance FPI-2265 in the
clinic, to the regulatory process or to commercialization;
management's expectations could be affected by unexpected patient
recruitment delays or regulatory actions or delays; uncertainties
relating to, or unsuccessful results of, FPI-2265 clinical trials,
including additional data relating to the ongoing and planned
clinical trials evaluating FPI-2265; the Company's ability to
obtain additional funding required to conduct its research,
development and commercialization activities; changes in the
Company's business plan or objectives; competition in general; the
Company's ability to obtain, maintain and enforce patent and other
intellectual property protection for FPI-2265; and the Company
partners' ability to advance any technology relating to
actinium-225 to development. Such forward-looking statements
involve known and unknown risks, uncertainties and other factors
that may cause actual results to be materially different from any
future results, performance or achievements expressed or implied by
such statements. These and other risks which may impact
management's expectations are described in greater detail under the
heading "Risk Factors" in the Company's annual report on Form 10-K
for the period ended December 31,
2023, as filed with the Securities and Exchange Commission
(the "SEC") and in any subsequent periodic or current report that
the Company files with the SEC. All forward-looking statements
reflect the Company's estimates only as of the date of this release
(unless another date is indicated) and should not be relied upon as
reflecting the Company's views, expectations, or beliefs at any
date subsequent to the date of this release. While Fusion may elect
to update these forward-looking statements at some point in the
future, it specifically disclaims any obligation to do so, even if
the Company's estimates change.
Investors and others should note that Fusion communicates with
its investors and the public using the Fusion website,
www.fusionpharma.com, including, but not limited to, company
disclosures, investor presentations, SEC filings, and press
releases. The information that Fusion posts on this website could
be deemed to be material information. As a result, Fusion
encourages investors, media and others interested to review the
information that Fusion posts there on a regular basis.
Contact:
Amanda
Cray
Senior Director of Investor Relations & Corporate
Communications
(617) 967-0207
cray@fusionpharma.com
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