YM BioSciences Reports Phase I/II Data for JAK Inhibitor CYT387 in
Myelofibrosis at ASH 2012
- 68% transfusion independence response rate and 37% durable
spleen response rate -
MISSISSAUGA,
ON, Dec. 9, 2012 /CNW/ - YM
BioSciences Inc. (NYSE MKT: YMI, TSX: YM) today reported
updated results from the 166 patient Phase I/II study of its
JAK1/JAK2 inhibitor, CYT387, for the treatment of myelofibrosis.
The results were presented this afternoon in an oral session at the
54th Annual Meeting of the American Society of
Hematology underway in Atlanta,
Georgia.
- 68% durable 12-week transfusion independence response rate with
a maximal duration of response approaching three years and
ongoing.
- The percentage of patients requiring transfusions decreased
substantially, from 44% at baseline to below 10% at week 40 of
treatment.
- 37% durable spleen response per IWG-MRT* with a maximal
duration of response of nearly 2.5 years and ongoing.
- The majority of subjects achieved a complete resolution or
marked improvement of common constitutional symptoms.
- The majority of adverse events were Grade 1.
"These data continue to demonstrate that
treatment with CYT387 results in significant, durable responses in
transfusion dependency, splenomegaly and constitutional symptoms,"
said Dr. Nick Glover, President and
CEO of YM BioSciences. "The benefits CYT387 produces are highly
encouraging for patients with myelofibrosis and underscore the
clinical potential of this drug."
*International Working Group for
Myelofibrosis Research and Treatment
Phase I/II Core Study Results
Study Design and Subject Disposition
The Core Study consisted of nine 28-day treatment cycles where
CYT387 was orally self-administered, primarily at dosages of 150 mg
once-daily (QD), 300 mg QD or 150 mg twice-daily (BID). Patients
who tolerated and benefited from the drug could continue to receive
CYT387 for an indefinite period beyond the Core Study in an
Extension Study. The 300 mg QD dosing regimen has been selected for
use in the anticipated Phase III clinical development program.
The median follow-up time for patients in the
Core Study and Extension Study is 16.9 months (range: 0.8 - 34.2
months; ongoing). During the Core Study, 42 patients (25%)
discontinued the study, eight for possibly or probably related
adverse events, for an overall retention rate of 75%.
Subject Baseline Characteristics
The majority of the 166 patients enrolled across the six study
sites have primary myelofibrosis (63%); 22% have post-polycythemia
vera myelofibrosis and 15% have post-essential thrombocythemia
myelofibrosis. Other patient characteristics include:
- DIPSS-Plus category: Int-1 - 10%; Int-2 - 62%; High - 28%
- RBC (Red blood cell) transfusion-dependent: 44%
- Palpable splenomegaly >10 cm: 79%
- Patients who had received previous therapies, including other
JAK inhibitors (13%) and IMiDs (9%).
Transfusion Independence Response
Of the 68 evaluable patients who were transfusion dependent at
baseline, 68% became transfusion independent for a minimum of 12
weeks during the Core Study. The median duration of the
transfusion-free period has not yet been reached (range: 85 - 988
days, ongoing). Of the transfusion dependent patients who did not
achieve a full transfusion independence response, 23% achieved at
least a 50% reduction in transfusion requirement in any 3-month
period.
The percentage of patients requiring
transfusions decreased substantially during the study, from 44% at
baseline to below 10% at week 40 of treatment.
Of the 28 evaluable patients who were
transfusion dependent at baseline and dosed at 300 mg QD, 75% have
become transfusion independent for a minimum of 12 weeks.
Three additional patients achieved a 12-week
transfusion independence response during the Extension Study.
Spleen Response
Of the 145 patients evaluable for spleen response by palpation, 37%
achieved a response per IWG-MRT. The median duration of spleen
response reported was 744 days (range: 56 - 859 days, ongoing).
Three additional subjects achieved spleen response during the
Extension Study.
During the Core Study, 50% of evaluable patients
achieved more than a 50% maximal decrease in spleen size from
baseline, with 87% achieving more than a 25% maximal decrease.
Of the 51 patients who were evaluable for spleen
response and dosed at 300 mg QD, 39% achieved a response per
IWG-MRT.
In the Core Study, 11 patients were evaluable
for spleen response by MRI. The response rate at six months was 45%
by MRI (defined as a 35% decrease in spleen volume) and the median
splenic decrease from baseline at six months was -41% by volume
measured by MRI.
Constitutional Symptoms Response
The majority of patients reporting constitutional symptoms at
baseline demonstrated a Complete Resolution or Marked Improvement
of their symptoms, including night sweats, pruritus and bone
pain.
Safety Results
CYT387 is well tolerated in myelofibrosis patients for dosing
periods currently up to three years and ongoing. The majority of
adverse events were Grade 1. Common reported adverse effects
include thrombocytopenia; transient, mild dizziness; mild
peripheral neuropathy; and abnormalities in liver/pancreas-related
laboratory tests. Treatment-emergent anemia and neutropenia were
rarely observed.
Oral presentation and YM conference
call:
The results from the Phase I/II study are being presented today at
5:15pm ET in an Oral Session at the
2012 Annual Meeting of the American Society of Hematology in
Atlanta, Georgia. YM will also
host a webcast meeting open to members of the investment community
to discuss the results. This event will be held from 6:30-7:30am ET on Monday,
December 10th in the Imperial Salon Room A of the
Atlanta Marriott Marquis, 265 Peachtree Center Ave. NE,
Atlanta, Georgia. Access to the
webcast will be available from YM's website at
www.ymbiosciences.com or at www.newswire.ca.
About CYT387:
CYT387 is an inhibitor of the kinase enzymes JAK1 and JAK2, which
have been implicated in a family of hematological conditions known
as myeloproliferative neoplasms, including myelofibrosis, and as
well in numerous other disorders including indications in
hematology, oncology and inflammatory diseases. Myelofibrosis is a
chronic debilitating disease in which a patient's bone marrow is
replaced by scar tissue and for which treatment options are limited
or unsatisfactory. Both the U.S. Food and Drug Administration (FDA)
and the European Commission have designated CYT387 an Orphan Drug
for the treatment of myelofibrosis.
About YM BioSciences
YM BioSciences Inc. is a drug development company primarily focused
on advancing CYT387, an orally administered inhibitor of both the
JAK1 and JAK2 kinases, which have been implicated in a number of
hematological and immune cell disorders including
myeloproliferative neoplasms and inflammatory diseases as well as
certain cancers. Positive interim results have been reported from a
Phase I/II trial of CYT387 in 166 patients with myelofibrosis. YM's
portfolio also includes several preclinical programs underway with
candidates from its library of novel compounds identified through
internal research conducted at YM BioSciences Australia.
This press release may contain
forward-looking statements, which reflect the Company's current
expectation regarding future events. These forward-looking
statements involve risks and uncertainties that may cause actual
results, events or developments to be materially different from any
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completion of clinical studies, the establishment of corporate
alliances, the impact of competitive products and pricing, new
product development, uncertainties related to the regulatory
approval process or the ability to obtain drug product in
sufficient quantity or at standards acceptable to health regulatory
authorities to complete clinical trials or to meet commercial
demand; and other risks detailed from time to time in the Company's
ongoing quarterly and annual reporting. Except as required by
applicable securities laws, we undertake no obligation to publicly
update or revise any forward-looking statements, whether as a
result of new information, future events or otherwise.
SOURCE YM BioSciences Inc.