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Preview of ASCO 2013: The Abstracts Expected to Generate the Most Buzz

The annual meeting of the American Society of Clinical Oncology (ASCO) is just around the corner, and Kantar Health is excited to preview the top abstracts. The 2013 meeting promises to be packed with the latest data and trends from the world of oncology, but it may not have an overwhelming number of practice-changing, blockbuster presentations compared with conferences in the recent past. The following is a brief synopsis of the three abstracts that are likely to generate the most discussion and have the highest impact. For a full discussion of all 10 of our top abstracts, please see the associated article in the May issue of OBR Green.

Avastin in Newly Diagnosed Glioblastoma

Avastin® (bevacizumab, Roche/Genentech) was granted accelerated FDA approval in 2009 for the treatment of relapsed glioblastoma (GBM). In November 2012, results for the Phase III AVAglio trial showed that adding Avastin to chemoradiotherapy for the treatment of newly diagnosed GBM patients improved progression-free survival (PFS), but the interim overall survival (OS) results did not reach statistical significance. Presented at ASCO this year will be the results from the RTOG 0825 trial that has a nearly identical trial design as AVAglio. This plenary presentation could serve to provide a more convincing narrative for the use of Avastin in the newly diagnosed GBM setting.

Physicians are becoming familiar with Avastin showing a PFS benefit but not significantly affecting OS. This may give some physicians pause after the AVAglio results followed this same pattern. Will the RTOG 0825 trial change that perception, or will we see a similar pattern of PFS without OS? The availability and high use of Avastin in relapsed GBM may certainly confound the OS results from these studies, so it will be interesting to see whether there is any trend in the data. Given the high unmet need in GBM and the complete lack of active agents beyond temozolomide, the PFS benefit could be enough to maintain Avastin as a new option in newly diagnosed patients, but lacking OS could hinder its ability to become the new standard of care. Presentations: RTOG 0825, Abstract 1, Sunday, June 2, 1:50 PM; AVAglio, Abstract 2005, Saturday, June 1, 4:30 PM

FIRE-3: We’re “Burning” to Finally See a Head-to-Head of Avastin versus Erbitux in Colorectal Cancer

In KRAS wild type colorectal cancer (CRC), Avastin is currently the first-line standard of care in combination with chemotherapy in the United States, but European physicians are utilizing about equal amounts of Erbitux compared with Avastin, according to Kantar Health’s most recent CancerMPact® Treatment Architecture data. Both targeted agents significantly improve PFS compared with chemotherapy alone, and both have demonstrated a strong trend to OS benefit in recent studies. In the absence of comparative data between the two agents, the current practice has evolved based on safety profile, cost of therapy and order of market entry. In the United States, the Cancer and Leukemia Group B (CALGB) sponsored the Phase III 80405 study, and in Europe a German academic group initiated the FIRE-3 study, both comparing first-line chemotherapy in combination with Avastin or Erbitux in KRAS wild type patients. FIRE-3 will be the first to report at ASCO 2013.

Several aspects of the data will be key to evaluate. PFS and OS will take top billing, but other endpoints such as response rate, resectability of liver metastases, safety and its impact on dose intensity will also influence treatment patterns. European physicians are more likely to be influenced by the FIRE-3 results, given that the treatment arms closely resemble the treatment standards in Europe. The impact on the U.S. market may be lower, since U.S. physicians typically use FOLFOX in the first line in combination with Avastin, so they may not see the FIRE-3 study as accurately depicting their first-line treatment of choice, as chemotherapy is limited to FOLFIRI in that study. The FIRE-3 results could raise some serious questions if Erbitux can show superiority versus Avastin on any of the efficacy endpoints. Presentation: FIRE-3, Abstract LBA3506, Saturday, June 1, 4:45 PM

Stage I Results from CLL11: Obinutuzumab Plus Chlorambucil in Fludarabine-Ineligible Chronic Lymphocytic Leukemia

As a CD20 antibody, obinutuzumab (also known as GA101, Roche/Genentech) draws frequent comparisons to Rituxan® (rituximab, Roche/Genentech), but Roche hopes the unique epitope and glycosylation of obinutuzumab will sufficiently distinguish it from Rituxan and ultimately prove superior.

The presentation at ASCO 2013 will detail the efficacy results from the first stage of the Phase III CLL11 trial comparing obinutuzumab plus chlorambucil versus chlorambucil alone. In January 2013, Roche announced via press release that obinutuzumab plus chlorambucil significantly reduced the risk of disease worsening or death compared with chlorambucil alone, and the study met the planned requirements of the futility analysis allowing its continuation. Additionally in that release, the company stated their plans to file for regulatory approval based on the results of this phase of the study.

It is not entirely surprising that the combination of obinutuzumab plus chlorambucil showed superiority versus chlorambucil monotherapy, but it will be the results versus Rituxan plus chlorambucil that will really generate some buzz if obinutuzumab is able to out-duel Rituxan in terms of efficacy. The oncology community will likely have to wait another year for that data, but the ASCO presentation should give an idea of the magnitude of benefit achieved by adding obinutuzumab to chlorambucil, which could hint at probabilities for success in the second stage of the trial. Presentation: CLL11, Abstract 7004, Tuesday, June 4, 9:15 AM

In addition to the abstracts above, the full article discusses the key abstracts listed in the table below.

By Josh Garcia, Associate Consultant, Clinical & Scientific Assessment, Kantar Health

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