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PHARMACEUTICAL NEWS
RIVAROXABAN
Bayer’s investigational anticoagulant rivaroxaban (Xarelto),
has been recommended for approval by the European Medicines Agency (EMEA) to prevent
deep-vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing hip
or knee replacement surgery. The Committee for Medicinal Products for Human Use
recommended the drug for approval in the European Union. Last month, Johnson &
Johnson (J&J) submitted a New Drug Application (NDA) to the United States FDA
seeking approval of this anticoagulant for the same indication. These filings are
based on the results of a pivotal phase III trial that demonstrated superior efficacy
of rivaroxaban compared to enoxaparin. The new drug is administered orally, once-a-day
and does not require monitoring.
BEVACIZUMAB
Roche has submitted an application to EMEA to extend its
label of bevacizumab (Avastin) so that it can be used in combination with docetaxel
chemotherapy for the first-line treatment of patients with metastatic breast cancer
(MBC). Bevacizumab is currently licensed in the European Union (EU) as first-line
treatment in patients with MBC in combination with paclitaxel. The filing is supported
by data from the phase III Avado trial comparing bevacizumab plus docetaxel with
docetaxel alone as first-line treatment which demonstrated that the combination
therapy significantly increased progression-free survival (PFS).
ROMIPLOSTIM
On August 22, 2008 the U.S. FDA approved Amgen’s romiplostim for
subcutaneous injection (Nplate™) for the treatment of thrombocytopenia in patients
with chronic immune (idiopathic) thrombocytopenic purpura (ITP) who have had an
insufficient response to corticosteroids, immunoglobulins, or splenectomy. The new
drug is a thrombopoietin (TPO) receptor agonist that stimulates bone marrow megakaryocytes
to produce platelets.
The safety and efficacy of romiplostim were evaluated in two clinical studies of
125 adult patients with chronic ITP who had completed at least one prior therapy
and who had baseline platelet counts ≤30,000 per microliter (mcL). One study enrolled
splenectomized patients and the other enrolled patients who had not undergone splenectomy.
They were randomized to receive romiplostim or placebo. Romiplostim was given subcutaneously
at an interval weekly dose of 1 mcg/kg and subcutaneously titrated to achieve and
maintain platelet counts between 50,000/mcL and 200,000/mcL.
The primary endpoint in both studies was “durable platelet response”
defined as at least six weekly platelet counts ≥50,000/mcL during the last 8 weeks
of study drug treatment, without rescue medications during the 24 week treatment
period. Romiplostim resulted in a durable platelet response in 61% of nonsplenectomized
patients and 38% who had undergone splenectomy. In pooled analysis of the 2 studies,
serious hemorrhage events were reported in 10% of the placebo groups and 6% of the
romiplostim groups. Romiplostim is not indicated for the treatment of thrombocytopenia
due to MDS or any cause of thrombocytopenia other than chronic ITP.
DENOSUMAB
Amgen has announced that results of a pivotal phase III
trial of its experimental bone drug denosumab in 7,800 postmenopausal women with
osteoporosis demonstrate that the drug reduced the risk of both spine and hip fractures
by statistically significant amounts compared with a placebo. The positive results
will allow the company to apply for regulatory approval of the drug. The data will
be presented at the American Society for Bone and Mineral Research meeting this
month. While researchers expected a reduction in spinal fractures, the primary goal
of the trial, they were somewhat surprised that denosumab also reduced hip fractures.
It also reduced the incidence of fractures elsewhere in the body, such as the arms
and legs.
Denosumab is a monoclonal antibody that targets and blocks the action of RANK ligand,
a protein that is involved with osteoclasts and plays a fundamental role in bone
metabolism. It has been shown to increase bone mineral density (BMD) in clinical
trials and recently was found to reduce the risk of osteoporosis and fractures in
a trial of 1,400 men with non-metastatic prostate cancer undergoing androgen deprivation
therapy. The company is also testing denosumab as a treatment for bone problems
of cancer patients with trials in metastatic bone disease underway. Compared to
bisphosphonates, which require pills be taken daily, weekly, monthly, or an intravenous
infusion once a year, denosumab’s different mechanism of action allows it to be
given by injection once every six months.
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FROM THE LITERATURE
MELANOMA:
Improved Outcome for Locally Advanced Disease
The final results of EORTC 18991, a randomized phase III trial evaluating adjuvant
therapy with pegylated interferon alfa-2b versus observation alone in resected stage
III melanoma were published in a recent issue of The Lancet along with
an editorial. The aim of the trial was to determine whether pegylated interferon
(pegIFN) alfa-2b can facilitate prolonged exposure (a maximum of 5 years) while
maintaining patient tolerability. Patients (N=1256) were randomized to observation
(N=629) or pegIFN alfa-2b (N=627) 6mcg/kg per week for 8 weeks (induction) then
3mcg/kg per week (maintenance) for an intended duration of 5 years and stratified
for microscopic (N1) vs macroscopic (N2) nodal involvement, number of positive nodes,
ulceration and tumor thickness. Primary endpoint was recurrence-free survival (RFS).
Median length of treatment with pegIFN alfa-2b was 12 months. At 3.8 years median
follow-up there were 328 recurrences in pegIFN group vs 368 in observation group
(HR 0.82; p=0.01); the 4-year rate of RFS was 45.6% in the IFN groups vs 38.9% in
the observation groups. There was no difference in OS between the groups. Grade
3 adverse events (A/E) occurred in 40% of patients receiving IFN vs 10% A/E in the
observation group; grade 4 A/Es were seen in 5% of the IFN group vs 2% in observation
group. Most common Grade 3 or 4 A/Es in pegIFN alfa-2b group were fatigue (16%),
hepatotoxicity (11%), and depression (6%). Treatment with pegIFN was discontinued
due to toxicity in 31% of patients.
Interpretation (of authors): Adjuvant pegIFN alfa-2b for stage III melanoma has
a significant, sustained effect on RFS.
Discussion (authors):
- Toxicity did not seem to increase with longer duration of treatment.
- In the N1 (microscopic nodal disease) population, the Kaplan-Meier
curves for RFS in the IFN and observation groups separate from one another increasingly
over time, suggesting that prolonged administration of pegIFN alfa-2b could be of
value.
Editorial Comments:
- More and more patients with stage III melanoma are now diagnosed
worldwide with N1 disease and these findings represent a very relevant subset for
therapy.
- The observation that primary tumor ulceration was associated with
benefit from pegylated IFN is particularly intriguing, and must be evaluated.
- In the near future, the prospects of combining pegIFN alfa-2b with
other agents in the adjuvant setting and evaluating it for maintenance use are real
possibilities.
- Further follow-up might show a significant survival advantage for
the N1 population; that would represent the real advance we have been waiting for.
Eggermont AMM, Suciu S, Santinami M, et al. Adjuvant therapy
with pegylated interferon alfa-2b versus observation alone in resected stage III
melanoma: final results of EORTC 18991, a randomised phase III trial. Lancet.
2008;372:117-126.
RENAL CELL CARCINOMA:
mTOR Inhibition Produces Impressive Results After Disease Progression
on VEGF TKIs
RAD001 (with the proposed brand name of Afinitor) is an orally administered inhibitor
of the mammalian target of rapamycin (mTOR), a therapeutic target for metastatic
renal cell carcinoma (mRCC). Results of a phase III, double-blind, randomized, placebo-controlled
trial of everolimus in 410 patients with mRCC whose disease had progressed on treatment
with VEGF receptor tyrosine kinase inhibitors (sunitinib, sorafenib, or both) have
demonstrated that treatment with everolimus prolongs PFS (the primary endpoint)
relative to placebo in this patient population. The study drug and the placebo were
given in conjunction with best supportive care. Findings: Results of the second
interim analysis indicated a significant difference in efficacy between arms and
the trial was halted early after 191 progression events were observed, 37% events
in everolimus group and 65% in the placebo group (HR 0.30, p<0.0001); median
PFS 4.0 months vs. 1.9 months favoring everolimus. At the time of the analysis,
median OS had not been reached for the everolimus group. As anticipated, A/Es were
more frequently reported for everolimus but these were mostly grade 1 or 2.
Treatment with VEGF receptor tyrosine kinase inhibitors has provided a significant
benefit to patients with mRCC but the therapy is not curative and a therapeutic
option was lacking after progression on these agents. On the basis of the results
of this trial, the authors feel that everolimus should now be considered as the
standard-of-care for this population of mRCC patients.
Motzer RJ, Escudier B, Oudard S, et al. Efficacy of everolimus in advanced renal
cell carcinoma: a double-blind, randomised, placebo-controlled phase III trial.
Lancet. 2008;372:449-456.
HEPATOCELLULAR CARCINOMA:
Improved Survival Seen In Advanced Disease with Sorafenib
The incidence of HCC is increasing in the U.S. and Europe, and it is the third highest
cause of cancer-related death globally, behind only lung and stomach cancers. No
systemic therapy has improved survival in patients with advanced HCC. A preliminary
study suggested that sorafenib (Nexavar), an oral multikinase inhibitor of the vascular
endothelial growth factor receptor (VEGFR), the platelet-derived growth factor receptor
β (PDGFR-β), and Raf may be effective in HCC. Results of this uncontrolled phase
II trial of a single-agent sorafenib demonstrated a median OS of 9.2 months and
a median time to progression (TTP) of 5.5 months.
On the basis of these data, investigators conducted a large (602 patient) phase
III, randomized, double blind, placebo-controlled trial to assess the efficacy and
safety of sorafenib in patients with advanced HCC who had not received previous
systemic treatment. Patients received either sorafenib 400 mg PO twice daily or
placebo. Primary outcomes were OS and the time to symptomatic progression. Secondary
outcomes were time to radiologic progression and safety.
At the second planned interim analysis, 321 deaths had occurred, and the study was
stopped. Median OS was 10.7 months in the sorafenib group and 7.9 months in placebo
patients (HR in sorafenib group, 0.69; p<0.001). There was no significant difference
between the two groups in the median time to symptomatic progression (4.1 months
vs. 4.9 months; p=0.77). The median time to radiologic progression was 5.5 months
in the sorafenib group and 2.8 months in the placebo group (p<0.001). Seven patients
in the sorafenib group (2%) and two patients in the placebo group (1%) had a partial
response; no patients had a complete response. Diarrhea, weight loss, hand-foot
skin reaction, and hypophosphatemia were more frequent in the sorafenib group.
Conclusions/Summary:
- This study showed that sorafenib prolonged median survival and the
time to progression by nearly 3 months in patients with advanced HCC.
- Future studies are warranted to evaluate sorafenib as an adjuvant
therapy after curative or locoregional therapies.
- Studies are needed to evaluate sorafenib in
combination with other molecular targeted therapies.
Llovet JM, Ricci S, Mazzaferro V, et al. Sorafenib in Advanced Hepatocellular Carcinoma.
N Engl J Med. 2008;378-390.
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Improving Outcomes for Resectable NSCLC
An Emerging Role for Vaccines
This clinical update is based on information presented
at a Live Webconference entitled “European Perspectives on Clinical Trials, Clinical
Practice, and Treatment Options in Lung Cancer” held on 9 June 2008 in Turin, Italy.
The speaker for this topic was Johan Vansteenkiste, MD, PhD from University Hospital
Leuven, Respiratory Oncology Unit, Leuven, Belgium. The entire program may be viewed
as a webcast at www.primeoncology.org.
Despite complete surgical resection of early stage NSCLC long tern outcomes remain
poor. Could vaccines provide an effective immunotherapeutic boost? Ongoing and planned
vaccine trials may soon be providing important answers.
Dr. Vansteenkiste pointed out that MAGE-A3 antigen is not expressed by normal cells
but is expressed by one-third of NSCLCs. This tumor specificity makes the antigen
an excellent target for vaccine therapy and contributes to a favorable toxicity
profile. A phase II randomized trial of 182 early stage (pathologic IB or II) patients
with MAGE-A3 (+) NSCLC who had complete resection of their disease received either
adjuvant MAGE-A3 immunotherapy or placebo postoperatively (Proc ASCO 2007, 25: Abst
7554). The vaccine therapy had an induction phase followed by maintenance (total
duration of 27 months). The primary endpoint was disease-free interval following
surgery and results favored the vaccine over placebo (HR 0.75, p=0.122). At nearly
5 years post-surgery, vaccine-treated patients OS curve plateaued at 67%, with a
trend toward improved survival compared to placebo (p=0.088).The most common side
effect was grade 1 or 2 local reactions at the injection sites. Only three grade
3 adverse events possibly related to vaccine therapy were noted.
Based on results of this phase II trial, a new large, global, phase III trial in
early stage NSCLC patients (2,270 patients) has been initiated for completely resected
MAGE-A3 (+) disease. In the MAGE-A3 (+) as Adjuvant Non-Small Cell LunG CanceR ImmunoTherapy
trial (MAGRIT), MAGE-A3 vaccine was given either after standard adjuvant chemotherapy
or instead of adjuvant chemotherapy. A decision for chemo vs no chemo is made by
patient and physician. If no chemo, then patients are randomized to MAGE-A3 vaccine
or placebo. If chemo is chosen, then up to 4 cycles are given followed by randomization
to receive either placebo or MAGE-A3 vaccine. The primary endpoint is DFS. This
trial is open for recruitment.
Dr. Vansteenkiste stated that other trials are being designed in which MAGE-A3 immunotherapy
is being considered for combination therapy either with chemotherapy or targeted
agents.
We welcome your comments and suggestions regarding content and format at
primelines@primeoncology.org.
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