Geron Corporation ( GERN )
shares fell more than 50% following the company's announcement
regarding the discontinuation of a phase II study (breast cancer)
being conducted with oncology candidate, imetelstat. Moreover, the
company said that chances of imetelstat achieving its primary
endpoint in a non-small cell lung cancer (NSCLC) study are pretty
Imetelstat is being evaluated in two more studies for essential
thrombocythemia and multiple myeloma.
The discontinued study was being conducted in metastatic
HER2-negative breast cancer patients who were randomized to receive
imetelstat plus paclitaxel or paclitaxel alone.
A scheduled periodic review by Geron`s Internal Safety
Monitoring Committee showed that the number of deaths and patients
discontinuing paclitaxel in the imetelstat arm was higher compared
to the control arm. As a result, the company decided to conduct an
unplanned interim analysis of efficacy which showed that median
progression-free survival (PFS) in the imetelstat arm was lower
compared to the paclitaxel arm (6.2 months versus 8.0 months).
While the number of deaths in the imetelstat arm (16 versus 10)
was higher, difference in overall survival was not statistically
significant. Based on all these findings, Geron decided to
discontinue the study.
Geron noted that the study protocol allowed for a reduction or
delay in paclitaxel dosing. The company said that a series of
analyses indicated that the reduction in paclitaxel dosing could
have been responsible for the PFS data.
In order to further investigate this possibility, Geron
conducted an unplanned interim safety and efficacy analysis of the
ongoing randomized phase II study in NSCLC patients. Imetelstat is
being evaluated as a single agent (maintenance treatment following
platinum-based induction chemotherapy) compared to observation in
this study. Patients in this study are receiving a higher and more
frequent dose of imetelstat compared to the HER2-negative
metastatic breast cancer study.
The interim analysis showed that median PFS was in favor of the
imetelstat arm (2.8 months versus 2.6 months) compared to the
observation-only arm. However, the difference was not statistically
Importantly, the company said that there was no indication that
imetelstat may be responsible for accelerating disease progression.
Although the company is continuing with the NSCLC study, it does
not expect the study to achieve the pre-specified success criteria.
As a result, the company does not expect to move imetelstat into
phase III studies for the NSCLC indication unless subsequent
analysis shows significantly different data.
As far as the hematologic malignancy studies are concerned,
Geron will continue with these studies. Results from these studies
should be out in the fourth quarter of 2012.
The discontinuation of imetelstat for breast cancer and the low
chances of moving the candidate into phase III development for
NSCLC is a major setback for Geron. Geron, which was previously a
leader in stem cell research, had shifted its focus to oncology
less than a year back.
Geron's pipeline consists of two candidates - imetelstat and
GRN1005. Given the imetelstat update, we have low expectations from
this candidate and expect investor focus to shift entirely to
GRN1005 which is currently in phase II studies for brain metastases
arising from non-small cell lung cancer and breast cancer.
The company expects to present interim data from the GRN1005
breast cancer trial (GRABM-B) in early December.
We prefer to remain on the sidelines until we see data on
GRN1005. We currently have a Neutral recommendation on Geron, which
carries a Zacks #3 Rank (short-term Hold rating).
GERON CORP (GERN): Free Stock Analysis Report
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