NEWARK, Calif., May 7, 2020 /PRNewswire/ -- Protagonist
Therapeutics, Inc. (Nasdaq:PTGX) today announced initial data from
the ongoing Phase 2 study of PTG-300 in patients with polycythemia
vera. The current results demonstrate that treatment with PTG-300
at individualized doses ranging from 10 mg to 80 mg for up to 28
weeks provided dose-related control of hematocrit levels and
eliminated the need for phlebotomy in all six out of six patients
that received the dosing as per protocol. A seventh patient with 12
weeks of treatment had an unintended dose interruption, received a
single phlebotomy, and remains on the study. In addition, positive
symptomatic measurements related to the ability of PTG-300 to
address iron deficiency in these frequently phlebotomized patients
were observed, with increases in serum ferritin values approaching
the range observed in healthy subjects. Patients enrolled in the
current study had received at least three phlebotomies within a 24
week period prior to PTG-300 treatment and were treated for up to
28 weeks as of the cutoff date of May 1,
2020 (range of 4 to 28 weeks, n=7 evaluable for efficacy).
Enrollment in the study continues and a total of eight patients
have enrolled to date.
"While further follow up and data from additional patients will
be needed to confirm the continuity of the robust clinical
responses observed to date, we believe that this study provides a
compelling rationale to initiate planning for a pivotal program in
polycythemia vera," commented Samuel
Saks, M.D., Protagonist Chief Medical Officer. "As a peptide
mimetic of the natural hepcidin hormone, PTG-300 is believed to
limit the excess number of red blood cells in polycythemia vera by
reducing iron available for red blood cell production. In the near
term, we are expanding the current study to include additional
patients as the Company focuses on these encouraging results. We
will also be hosting a scientific planning meeting with leaders in
the field of myeloproliferative neoplasms and working with patient
advocates to discuss pivotal and future studies in polycythemia
vera. Our goal with these studies is to work to address the broad
populations of patients that may benefit from this new
non-cytoreductive treatment."
"These initial data demonstrate the potential of PTG-300 to
almost entirely avoid the need for phlebotomy in the treatment of
polycythemia vera by persistent control of hematocrit levels to
below 45 percent," commented Ronald
Hoffman, M.D., Director of the Myeloproliferative Diseases
Program at The Icahn School of Medicine at Mount Sinai and an
investigator in the PTG-300 polycythemia vera study. "Previous
studies have repetitively demonstrated that patients undergoing
phlebotomy in addition to other therapies spend far too much time
above the target hematocrit levels of 45 percent in the clinical
guidelines. This is despite the fact that hematocrit levels above
this target are associated with significant cardiovascular events
such as heart attack and stroke. PTG-300 offers the possibility of
maintaining patients consistently below 45 percent hematocrit
levels with weekly administration of a mimetic of the endogenous
iron regulator without the up and down excursions inherent in
typical phlebotomy therapy. In addition, the reduction in
phlebotomy may allow sufficient iron to be available systemically
to avoid symptoms related to iron deficiency. The potential for
weekly self-administration with PTG-300 is a meaningful advantage
of this approach to treatment. These early results are very
encouraging and suggest the potential for a paradigm shift for the
treatment of polycythemia vera. We look forward to additional data
from the expanded study in the future."
Administration of PTG-300 was well tolerated and the safety
profile was generally similar with results of prior studies, with
injection site reactions and bruise as the only observed adverse
events. With eight subjects enrolled to date, the study continues
to accrue patients and none of the patients have discontinued
treatment with PTG-300.
The study is designed to monitor the safety profile and to
obtain evidence of efficacy in patients requiring frequent
phlebotomies. Based on the initial findings, the study is being
expanded and is now expected to enroll approximately 50 patients.
The study design consists of a 16-week open-label dose escalation,
reduction, or maintenance stage every four weeks from 10 mg to 80
mg and a 12-week maintenance period at doses that generate desired
hematocrit levels followed by a randomized and blinded withdrawal
stage up to 12 weeks. The study has an open-label extension for up
to one year to monitor long-term safety and other effects. The
primary endpoint is the proportion of responders during the blinded
randomized withdrawal period. Other endpoints of this clinical
proof-of-concept study include measurement of blood parameters
(hematocrit and hemoglobin levels), reductions or delay in
phlebotomy requirements and improvements in quality-of-life
symptoms. Additional information is available at
https://clinicaltrials.gov/ct2/show/NCT04057040.
Conference Call and Webcast Information
Protagonist will host a conference call at 5 p.m. EDT / 2 p.m.
PDT today to provide a corporate update. Ronald Hoffman, M.D., Director of the
Myeloproliferative Diseases Program at The Icahn School of Medicine
at Mount Sinai, will join the call to present initial results for
PTG-300 in polycythemia vera. To access the live call, dial
1-844-515-9178 (U.S./Canada) or
1-614-999-9313 (international) and refer to conference ID number
4597494. A live and archived webcast will also be accessible in the
Investors section of the Company's website at
www.protagonist-inc.com.
About Protagonist Therapeutics, Inc.
Protagonist Therapeutics is a clinical stage biopharmaceutical
company that utilizes a proprietary technology platform to discover
and develop novel peptide-based therapeutics to address significant
unmet medical needs and transform existing treatment paradigms for
patients. The Company currently has three clinical-stage assets.
PTG-300 is an injectable hepcidin mimetic in development for the
treatment of polycythemia vera and hereditary hemochromatosis.
PTG-200 is an orally delivered, gut-restricted, interleukin-23
receptor specific antagonist peptide in development for the
treatment of inflammatory bowel disease, with Crohn's disease as
the initial indication. The Company has a worldwide license and
collaboration agreement with Janssen Biotech, Inc., for the
development of PTG-200. PN-943 is an orally delivered,
gut-restricted alpha-4-beta-7 integrin specific antagonist peptide
in development for the treatment of inflammatory bowel disease,
with ulcerative colitis as the initial targeted indication.
Protagonist is headquartered in Newark, California. For further information,
please visit www.protagonist-inc.com.
Cautionary Note on 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. Forward-looking statements
include statements regarding our intentions or current expectations
concerning, among other things, the potential for our clinical
programs, the potential of PTG-300 as a possible treatment
for polycythemia vera, the Company's success at finding
appropriate doses of PTG-300 for the treatment of polycythemia
vera, planning for a pivotal program in polycythemia vera, the
results of the Phase 2 study of PTG-300 in polycythemia
vera, the results of future studies for the treatment of
polycythemia vera, plans for future clinical trials, the
initiation and availability of results of our clinical trials and
the sufficiency of our financial resources, our ability to fund our
clinical trials, the initiation of and enrollment of patients in
our clinical trials including trails related to PTG-300 as a
possible treatment for polycythemia vera, the results of clinical
trials and the outlook for our other programs. In some cases, you
can identify these statements by forward-looking words such as
"will," "plan," "believe," "may," "potential," "expect," or the
negative or plural of these words or similar expressions.
Forward-looking statements are not guarantees of future performance
and are subject to risks and uncertainties that could cause actual
results and events to differ materially from those anticipated,
including, but not limited to, our ability to develop and
commercialize our product candidates, our ability to earn milestone
payments under our collaboration agreement with Janssen, our
ability to use and expand our programs to build a pipeline of
product candidates, and our ability to obtain and maintain
regulatory approval of our product candidates. Additional
information concerning these and other risk factors affecting our
business can be found in our periodic filings with the Securities
and Exchange Commission, including under the heading "Risk Factors"
contained in our Quarterly Report on Form 10-Q for the period ended
March 31, 2020, filed with the
Securities and Exchange Commission. Forward-looking statements are
not guarantees of future performance, and our actual results of
operations, financial condition and liquidity, and the development
of the industry in which we operate may differ materially from the
forward-looking statements contained in this press release. Any
forward-looking statements that we make in this press release speak
only as of the date of this press release. We assume no obligation
to update our forward-looking statements, whether as a result of
new information, future events or otherwise, after the date of this
press release.
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SOURCE Protagonist Therapeutics, Inc.