Study Demonstrates Radioembolization Using SIR-Spheres Significantly Improves Overall Survival for Patients With Inoperable Colorectal Cancer

MAGDEBURG, Germany, October 21, 2012 /PRNewswire/ –

Survival of patients treated with SIR-Spheres more than double that of patients who
received best supportive care, benefit rivals that found with new biological agents,
authors note

The results of a matched-pair comparison of patients with metastatic colorectal cancer
predominately affecting the liver, for whom all chemotherapy options had been exhausted,
showed that the addition of radioembolization using SIR-Spheres significantly prolonged
survival compared with best supportive care (BSC) alone.[1]

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The study, published in October’s edition of Cardiovascular and Interventional
Radiology, showed that median overall survival was more than doubled in patients receiving
radioembolization plus BSC versus BSC alone: 8.3 months vs. 3.5 months (hazard ratio [HR]
0.26; 95% confidence interval 0.15-0.48; P<0.001). A multivariate analysis confirmed that
radioembolization was the only significant predictor for prolonged survival among all the
baseline parameters investigated (HR 0.30; 95% CI 0.16-0.55; P<0.001).

“Radioembolization significantly prolonged overall survival compared with supportive
care alone in a well-matched cohort of patients with extensive, liver-dominant
chemotherapy refractory disease for whom there are limited treatment options,” said Prof.
Jens Ricke, Director of Radiology and Nuclear Medicine at the University Hospital of
Magdeburg, Germany, and senior author of the study. “The evidence suggests that
radioembolization should be considered as a treatment option for patients with liver-only
or liver-dominant colorectal metastases who have failed or are intolerant of
chemotherapy.”

About the Study

The study compared the overall survival of 58 patients with colorectal cancer
metastases that were either limited to or predominately affected the liver, who were
refractory to all recommended chemotherapy or had refused further chemotherapy, and were
unsuitable for other treatment options such as surgical resection, local ablation or other
forms of radiotherapy. Twenty-nine patients received radioembolization using SIR-Spheres
(90Y-labeled resin microspheres; Sirtex Medical Limited, Sydney, Australia) and were
followed prospectively. These patients were matched retrospectively for prior treatments
and tumour burden with a contemporary cohort of >500 patients who received BSC from 3
centres in Germany to identify 29 consecutive patients with at least 2 of 4 specific
matching criteria (the presence of synchronous or metachronous metastases, tumour burden,
increased alkaline phosphatase, and/or carcinoembryonic antigen [CEA] >200 U/mL). The
primary endpoint of the study was overall survival.

Following radioembolization, 12 patients (41.4%) had a partial response and a further
5 (17.2%) had stable disease, giving a disease control rate of 58.6%. The progression-free
survival was 5.5 months in the radioembolization cohort compared to 2.1 months in those
receiving BSC. The adverse events following radioembolization were generally
mild-to-moderate in nature, predominately transient, self-limiting and manageable.

“The results of this study are consistent with those from similar cohorts of
chemotherapy-refractory patients with colorectal liver metastases treated using
radioembolization,” said Dr Ricarda Seidensticker, consultant interventional radiologist
and lead author of the study. “This was the first comparative study of radioembolization
to use overall survival as the primary endpoint, in an ethical design that avoided the
crossover of patients to active therapy, which usually blunts the ability of trials to
show a difference in survival. These results also compare favourably with recent studies
using new biological agents to treat metastatic colorectal cancer. In one randomized
controlled trial of cetuximab, for example, the median overall survival was 6.1 months
versus 4.6 months with best supportive care. In a similar trial with panitumumab, median
overall survival was 6.4 months versus similar survival with best supportive care followed
by crossover to panitumumab at progression.”

Large international randomised controlled trials are currently evaluating the
effectiveness of radioembolization using SIR-Spheres combined with first-line chemotherapy
in the treatment of patients with colorectal cancer liver metastases compared to
chemotherapy alone in order to assess whether this treatment should be used as an early
intervention.

About Colorectal Cancer

In 2008, 153,000 people in the United States of Americans and 333,000 in the European
Union were diagnosed with colorectal cancer.[2] Around half of these patients will develop
metastases that have spread from the original site of the disease, predominately to the
liver. Up to 90% of these patients ultimately die from liver failure due to the spread of
the disease. Radioembolization (also called Selective Internal Radiation Therapy or SIRT)
is a novel approach to treating liver tumours using microspheres labelled with radioactive
yttrium-90 (90Y). The microspheres are implanted by interventional radiologists to
selectively target the tumours with radiation while sparing the remaining healthy liver
tissue.

The 3 centres involved in the study (and the numbers of control patients screened)
were:

        - University Hospital of Magdeburg, Germany / Universitatsklinikum Magdeburg
          (n = 348);
        - Charite Campus, University Hospital of Berlin, Germany / Universitatsmedizin
          Berlin (n = 120);
        - Magdeburg Hospital, Germany / Klinikum Magdeburg (n = 86).

SIR-Spheres are approved for use in Australia, the European Union (CE Mark), New
Zealand, Switzerland, Turkey and several other countries for the treatment of unresectable
liver tumours.

SIR-Spheres are also fully FDA-approved and are indicated in the U.S. for the
treatment of non-resectable metastatic liver tumours from primary colorectal cancer in
combination with intra-hepatic artery chemotherapy using floxuridine.

References:

        1) Seidensticker R, Denecke T, Kraus P et al. Matched-pair comparison of
          radioembolization plus best supportive care versus best supportive care alone for
          chemotherapy refractory liver-dominant colorectal metastases. Cardiovascular and
          Interventional Radiology 2012; 35(5): 1066-1073.
        2) International Agency for Research on Cancer. GLOBOCAN 2008: Colorectal Cancer
          Incidence and Mortality Worldwide in 2008.
          http://globocan.iarc.fr/factsheets/cancers/colorectal.asp accessed 12/8/2011.

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SOURCE University of Magdeburg