Eribulin Mesylate Demonstrated Anti-Tumor Activity in Heavily Pretreated Patients With Advanced Breast Cancer

London (ots/PRNewswire) -

- Phase II Data Presented at ASCO Showed Acceptable Tolerability
Profile, with Low Incidence of Grade 3 and 4 Neuropathy

Eisai Europe Ltd. The investigational chemotherapeutic agent
eribulin mesylate (E7389) demonstrated activity in a heavily
pretreated population of women with locally advanced or metastatic
breast cancer, according to results of a multi-center Phase II
clinical trial. The study also suggests that eribulin mesylate has a
manageable tolerability profile, with a low incidence of Grade 3
(severe) and no Grade 4 (disabling or life-threatening) neuropathy.
These data (abstract #1084) will be presented at the 44th Annual
Meeting of the American Society of Clinical Oncology (ASCO) on
Monday, June 2 from 2 to 6 p.m. at S Hall A1 of McCormick Place.

"The anti-tumour activity of eribulin mesylate, as observed in
this study, is encouraging, given the limited treatment options for
women with advanced breast cancer who have previously received
multiple lines of therapy," said lead investigator Linda T. Vahdat,
MD, of Weill Cornell Medical College in New York. "The subjects in
this trial had received a median of four prior chemotherapy regimens
that included an anthracycline, a taxane and capecitabine."

About Study 211 (Data on file)

Study 211 is a Phase II, open-label, single-arm study evaluating
the efficacy and safety of eribulin mesylate in patients with locally
advanced or metastatic breast cancer who had received an
anthracycline, a taxane and capecitabine as prior therapy, and who
were refractory to their last chemotherapy regimen, as documented by
progression on or within six months of that therapy.

Of 299 patients enrolled in the study, 291 were treated with
eribulin mesylate. The median age of those patients was 56 years
(range: 26-80 years). Eribulin mesylate was administered at a dose of
1.4mg/m2 as a 2- to 5-minute intravenous infusion on Days 1 and 8 of
a 21-day cycle. Patients received a median of four cycles of eribulin
mesylate (range 1-27). No premedication to prevent hypersensitivity
was required.

Two-hundred sixty-nine patients met the key inclusion criteria.
In patients who received a median of four cycles of eribulin
mesylate, Overall Response Rate (ORR) by Independent Review (IR) was
9.3% (all Partial Responses (PR); 95% confidence interval (CI):
6.1%-13.4%). Investigator-assessed ORR was 14.1% (1 CR; 95% CI:
10.2%-18.9%). Nearly half (46.5%) the patients had stable disease
(SD) after treatment with eribulin mesylate. The clinical benefit
rate (CBR, defined as CR+PR+SD equal to or more than 6 months) was
17.1% (95% CI: 12.8%-22.1%).

The median duration of response was 4.2 months (126 days, range:
42(1)-258 days; 95% CI: 86-147). Median progression-free survival
(PFS) was 2.6 months (79 days, range: 1*-397 days), and the median
overall survival (OS) rate was 10.3 months (315 days, range: 19-604
days; 95% CI: 279-350). The six-month PFS and OS rates were 16.0%
(95% CI: 8.6-17.0) and 72.3%, respectively (95% CI: 66.9-77.6).

The safety analysis included all 291 patients who received
treatment with eribulin mesylate. Patients with up to Grade 2
peripheral neuropathy were included in the study. The most frequently
reported Grade 3 (severe) or Grade 4 (disabling or life- threatening)
adverse events were neutropenia (a decrease in the number of granular
white blood cells, 54%); febrile neutropenia, 5.5%, leukopenia (low
white blood cell count, 14%), and weakness/fatigue (10%; no Grade 4
events). Grade 3 peripheral neuropathy (a functional disturbance or
damage to nerves outside the brain and spinal cord) was reported in
5.5% of patients. No Grade 4 peripheral neuropathy events were
reported.

No correlation was seen between Grade 2 peripheral neuropathy and
deterioration.

"In this study, eribulin mesylate appeared to have an acceptable
tolerability profile, particularly with regard to the low incidence
of peripheral neuropathy," noted Vahdat. "None of the reported cases
of neuropathy were disabling, suggesting that eribulin mesylate, if
approved, may be a useful addition to the treatment armamentarium for
advanced breast cancer."

Note to Editors

About Eribulin Mesylate (Data on file)

Eribulin mesylate is being developed by Eisai as a potential new
chemotherapeutic agent. It suppresses the growth of microtubules,
which are involved in various cellular processes in the body, such as
cell division. Eribulin mesylate is a synthetic analog of
halichondrin B, a naturally occurring compound which was first
isolated from a marine sponge Halichondria okadai in 1992.

About Eisai Europe Ltd.

Established in 1989, Eisai Europe Ltd. is the European
pharmaceutical subsidiary of Eisai Co. Ltd., a research-based human
health care (hhc) company that discovers, develops and markets
products throughout the world. Through a global network of research
facilities, manufacturing sites and marketing subsidiaries, Eisai
actively participates in all aspects of the worldwide health care
system. Eisai focuses its efforts in two main therapeutic areas;
integrative neurology and integrative oncology/critical care. Eisai
employs more than 9,500 people worldwide.

(1) Censored observation.

ots Originaltext: Eisai Europe Limited
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Contact:
For further information please contact: Andrew Day, Communications
Director, Eisai Europe Ltd, +44(0)208-600-1400, +44(0)7973-411-419