Malignant gliomas remain among the most devastating cancers, and especially for recurrent
GBM no standard treatment has been established to date.
ZK 219477 is a fully synthetic analogue of Epothilone B, a naturally occurring cytotoxic
substance. ZK 219477 inhibits microtubule depolymerization, causing cell cycle blockage
in G2/M phase and induction to apoptosis. This mechanism of action is similar to that of
taxanes (paclitaxel and docetaxel), but epothilones retain activity against multi-drug
resistance (MDR) tumours. ZK 219477 demonstrated both in vitro and in vivo considerable
anti-tumour activity against a wide range of malignancies, and it is now about to enter
phase II studies in a number of selected indications. In pre-clinical model ZK 219477 has
demonstrated anti-tumorigenic activity for gliomas tumours both in vitro and in vivo.
ZK 219477 has the ability to cross the blood-brain barrier, a fundamental characteristic
for a potential GBM chemotherapy. In a preclinical PK study, similar concentrations of ZK
219477 were detected in plasma (1.2 μg/ml) and brain (0.9 μg/g) after 10 min after i.v.
application in scid mice. The AUC brain/AUC plasma was about 0.8, indicating a free
access to the brain (Hoffmann J et al. 2004, European Journal Cancer Supplement 2, N 8,
p. 159, Abstract 521, ref.17). ZK 219477 produced strong antiproliferative activity in
the human glioma cell line U373 inoculated subcutaneous in nude mice (2 mg/kg and 9
mg/kg) as well as paclitaxel (8 mg/kg), but on the contrary of paclitaxel, only ZK 219477
demonstrated antitumour activity against U373 implanted in nude mice (9 mg/kg): 8
complete response out 9 treated mice.
Of interest for GBM indication, ZK 219477 is not metabolized by liver cytochrome P450,
which is induced by phenytoin and other anti-convulsion drug, commonly used in
post-surgery GBM patients.
The purpose of this single arm phase II study is to evaluate safety and efficacy of ZK
219477 in the treatment of pre-treated, recurrent GBM patients. Aim of the study: The
purpose of this single arm phase II study is to evaluate safety and efficacy of ZK 219477
in the treatment of pre-treated, recurrent GBM patients. An optional PK study will be
performed in selected patients.
Study Design: Open, monocentric, not randomised, single arm, phase II study. Study
medication: ZK 219477 epothilone B analog. Study Population: 15 recurrent glioblastoma
patients previously treated by surgery, conventional radiotherapy and chemotherapy with
temozolomide (TMZ. The 15 patients for this study, represent the first stage of
recruitment according to the statistical design.
Inclusion Criteria:
- - Histologically proven (at diagnosis) GBM.
- - Age between 18 and 70 years.
- - Life expectancy of at least 3 months.
- - Presence of at least one bi-dimensionally measurable lesion on gadolinium
(Gd)-enhanced MRI, indicating progressive or recurrent disease at least 8 weeks
after standard external-beam radiotherapy.
- - Recurrence or progression after treatment with radiotherapy and temozolomide.
Also
patients with residual disease after surgery for recurrent GBM will be included.
- - Adequate bone marrow reserve (leukocytes ≥ 3,500/ml, ANC ≥ 1,500/ml, platelets
≥100,000/ ml); normal baseline liver (serum bilirubin ≤ 20 /mol/ L), renal (serum
creatinine <150 /mol/L) and cardiac function.
- - Absence of infectious disease, debilitating chronic diseases, and known psychiatric
disorders.
- - Corticosteroid dose stable for at least 1 week.
- - Adequate recovery from previous surgery, radiation and chemotherapy.
- - Negative pregnancy test at enrolment in females of child-bearing potential.
- - Agreement to use highly effective contraception methods in adults of reproductive
potential.
- - Fully informed written consent.
Exclusion Criteria:
- - Patients who have had chemotherapy or radiotherapy within 4 weeks.
- - History of allergic reactions attributed to compounds of similar chemical or
biologic composition to ZK219477.
- - Uncontrolled inter current illness including, but not limited, to ongoing or active
infection, symptomatic congestive heart failure,unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance
with study requirements.
- - Any prior treatment with epothilones, other tubulin-targetting as taxanes (e.g.
paclitaxel, docetaxel) and vinca alkaloids (e.g.vincristine, vinblastine,
vinorelbine)
- Peripheral neuropathy.
- - Any concurrent malignancy other than non-melanoma skin cancer or carcinoma in situ
of the cervix.
- - Subjects who have received an experimental drug or have participated in a clinical
trial within 3 months prior to screening.
- - Employees of the investigator or study centre with direct involvement in the
proposed study or other studies under the direction of that investigator or study
centre.
Treatments:
Treatment will be administered on an inpatient basis. ZK 219477 will be administered as
an i.v. infusion of 3 hours duration at a dose of 16 mg/m2 BSA every three weeks.
Two dose reductions are allowed in order to manage toxicities: 12 mg/m2 and 9 mg/m2.
Evaluation criteria:
Efficacy evaluation. Primary end-point: Progression Free Survival at 6 months (PFS-6).
Secondary end-points: Response rates (CR +PR), Median Survival Time (MST). Safety
evaluation. Treatment toxicity will be assessed using CTCAE, Version 3.0, except for
neurological toxicity that will be assessed also by means of the Scottish Gynaecological
Cancer Trials Group (SGCTG) Neurotoxicity Score and electromyography.
Statistics:
A group-sequential design will be used with the chance of remaining alive and free of
progression at 6 months, called "response", as primary endpoint. The null hypothesis of a
response rate ≤ 10% will be tested based on the binomial distribution of the response
endpoint at a nominal significance level of 0.10 (one-sided). If the observed response
rate in the 15 patients is < 20%, the null hypothesis will be accepted and study failure
will be concluded. If the observed response rate is ≥ 20% (i.e., at least three out of
the 15 patients show a response after 6 months), then consideration would be given to
studying further. If the observed response rate amounts to at least 5 out of the initial
15 patients, the null hypothesis will be rejected and the study may be stopped after the
first stage. Secondary end-points: PFS and MST will be estimated using the Kaplan-Meier
method.
Response, age, KPS, number of surgical procedures performed, previous low grade, and time
between end of radiotherapy and start of chemotherapy will be considered variables
possibly related to TTP and the time interval between start of chemotherapy and death
from any cause (MST). Descriptive statistics with these classified time-to-event
variables as subgroups will be provided
