Aspirin trial seeks to tackle colorectal cancer in Asia

Medical Tribune September 2009 P8
David Brill

A major new trial is set to launch in Asia to establish whether aspirin can prevent recurrence of colorectal cancer.

The ASCOLT study will involve over 2,000 patients from centers across Southeast Asia, China and India, and will be led jointly by the National Cancer Centre Singapore (NCCS) and the University of Oxford, UK.

Patients will be randomized to aspirin (200mg/day) or placebo for 3 years, following surgery and adjuvant chemotherapy for high-risk stage II and III colorectal cancer. The primary endpoint will be disease-free survival over 5 years of follow-up.

A growing body of evidence suggests that aspirin is effective for primary prevention of colorectal cancer, but ASCOLT is thought to be the first prospective clinical study to investigate the drug in the adjuvant setting after chemotherapy.

If positive, the results could have a huge impact on the treatment of colorectal cancer in Asia and worldwide, according to Dr. Toh Han Chong, head of the department of medical oncology at NCCS and one of the ASCOLT lead investigators.

“It’s incredible how many people you could save from relapse with the addition of aspirin if this study is positive. If you go to a village in India you can’t really give costly [monoclonal antibodies], so there is compelling power of social responsibility here,” he told Medical Tribune.

“We have undervalued the power of simple drugs. It’s time to redress the balance – change the paradigm and go cheap.”

Recruitment for ASCOLT is already underway, with centers confirmed in Singapore, Hong Kong, Jakarta and several cities in India.

More study centers are still needed in order to reach the target of 2,000 patients however said Toh, who extended the invite to all Asian delegates at the recent ‘Best of ASCO’ conference in Singapore.

“It’s a drug trial that cannot be done in the West. Many people over the age of 50 in the US are popping aspirin over the counter for heart conditions or stroke prevention,” he said. “Fewer people are on aspirin in Asia. That’s why it’s a perfect study to do here.”

Colorectal cancer is the second leading cause of cancer death in North America, Europe and Australasia according to a 2007 global report from the American Cancer Society. In Southeast Asia, it is the third biggest killer (behind liver and lung cancer) – responsible for 7.9 percent of cancer deaths.

In Singapore, colorectal cancer is the leading cancer among men and the second most common among women, data from the national cancer registry show.

A recent study found that regular use of aspirin after a diagnosis of colorectal cancer was associated with lower overall mortality (hazard ratio [HR] 0.79; 95% CI 0.53 – 0.95) and cancer-specific mortality (HR 0.71; 0.53 – 0.95), after a median of 11.8 years of follow-up. [JAMA 2009;302(6):649-58]

A 2007 paper, meanwhile, reported that taking 300 mg/day or more of aspirin for 5 years was effective for primary prevention of colorectal cancer, according to pooled data from two large randomized trials (HR 0.74; 95% CI 0.56 – 0.97; P=0.02). [Lancet 2007;369(9573):1603-13] Earlier trials have also shown that aspirin can prevent colorectal adenomas – the precursors to cancer – both in patients with, and without, a prior history of cancer. [N Engl J Med 2003;348(10):883-90; N Engl J Med 2003;348(10):891-9]

“Why should oncologists do an aspirin trial? Because the epidemiological data is strong, the data on polyp reduction is very convincing, the retrospective observational studies are very compelling and remarkable in terms of hazard ratios, and the data preclinically is scientifically robust,” added Toh.

ASCO award set to boost Asian cancer research

Medical Tribune September 2009 P8
David Brill

A Singapore oncologist has become the first Singaporean, and one of the first Asia-based recipients, to pick up a prestigious research award from the American Society of Clinical Oncology (ASCO).

Dr. Daniel Tan of the National Cancer Centre Singapore (NCCS) will receive a US$50,000 grant as part of the Young Investigator Award, bestowed by the ASCO cancer foundation.

The money will help fund his research on the molecular mechanisms of tyrosine kinase inhibitors (TKIs) in nasopharyngeal cancer. The work aims to understand why some patients respond better to targeted therapies than others – so as to improve patient selection and avoid unnecessary exposure to ineffective treatment and side effects.

“One of the challenges with any of these new-generation drugs is to find out how we can use them better – to get the right drug to the right patient. Understanding the reasons for response and resistance can also allow us to develop much more effective treatment strategies that hopefully translate to improved survival,” said Tan, who will work alongside his mentor Professor Teh Bin Tean, director of the NCCS-VARI laboratory – a joint project with the Michigan-based Van Andel Research Institute.

Tan’s ASCO proposal was borne out of clinical observations from a phase II trial of pazopanib, which saw a subset of nasopharyngeal cancer patients respond better to therapy than others. This trial is currently ongoing under principal investigator Dr. Darren Lim, a senior consultant at NCCS specializing in thoracic and head and neck cancers.

The goal now is to understand which proteins are targeted by the drug, and how this differs between patients and tumor types. Tan’s work will be done largely in a series of co-culture experiments and mouse xenograft models – allowing detailed analysis of how the drug affects each cellular compartment within a tumor.

Tan is also aiming to secure more local funding for his research, and hopes in the long term to help establish a comprehensive drug development program, which would also provide patients with access to novel therapeutic agents.

He added that he was pleased to receive the award, and is especially encouraged that the proposal was deemed to have sufficient scientific merit for further study.

“It is heartening to know that one’s ideas are being taken seriously by a highly regarded scientific body. Furthermore, the award is rarely given out to institutions outside of America, so it’s a nice endorsement of the research infrastructure at NCCS,” he said.

Cetuximab offers hope for Asian lung cancer patients

Medical Tribune September 2009 P8
David Brill

A novel lung cancer therapy could be of particular benefit to Asian patients, results of a recent trial suggest.

The international FLEX* study reported that adding the monoclonal antibody cetuximab to chemotherapy prolonged survival of advanced lung cancer patients from 10.1 months to 11.3 months.

Further analysis revealed, however, that Asians treated with the drug survived for a median of 19.5 months, whereas non-Asians survived only 9.6 months.

The randomized trial involved 1,125 patients – 121 of whom were from Asian centers (predominantly in Hong Kong, Taiwan, Singapore and South Korea). [Lancet 2009;373(9674):1525-31]

There are several possible explanations for the ethnic discrepancy but also questions that remain unanswered, according to Professor Kenneth O’Byrne, one of the FLEX investigators, who spoke to Medical Tribune during the recent ‘Best of ASCO’ conference in Singapore.

Asian lung cancer patients are more likely to be women, non-smokers and have adenocarcinomas than non-Asian patients – all groups which tend to survive longer, he said. Moreover, epidermal growth factor receptor (EGFR) mutations are more common among Asians – a characteristic which not only improves prognosis in itself, but also makes patients eligible for first-line EGFR tyrosine kinase inhibitors which can further improve outcomes.

“So there is a combination of reasons as to why but it’s not just that – there may be some intrinsic sensitivity to treatment here that’s not present in the West,” said O’Byrne, adding that further study is needed to better understand these biological similarities and differences.

Cetuximab is presently licensed for use only in colorectal and head and neck cancers. An application for lung cancer licensing was recently rejected by the European Medicines Agency (EMEA), but is currently under appeal from the manufacturer, Merck Serono.

The verdict has also come as a surprise to many experts in the field and will face “a strong challenge,” said O’Byrne, a consultant medical oncologist at St. James’s Hospital and a clinical professor at Trinity College, Dublin, Ireland. The FLEX trial was published before the EMEA decision, with investigators concluding that cetuximab can be considered as standard first-line therapy for all patients with advanced non-small cell lung cancer (NSCLC).

“Cetuximab is the first drug to show a survival benefit in all histological types: adenocarcinoma, squamous carcinoma – across the board. Secondly, the toxicities are all very predictable – we know how to manage them and they’re straightforward. Thirdly, not only was the FLEX trial positive but when you take in all the other trials together … as a collective they show a positive result,” said O’Byrne. He added that US National Comprehensive Cancer Network guidelines already recommend that the drug be considered for lung cancer patients, and that many oncologists in Europe have begun off-label usage.

O’Byrne acknowledged that cetuximab therapy would be costly, but noted that around half of patients display a strong predictive marker in the form of a skin rash, which develops after one round of chemotherapy. These patients tend to survive for around an extra 5 months, which may justify the cost, he said. More work is needed to confirm whether cetuximab offers any benefit for those who do not develop a rash, but it appears likely that therapy could be discontinued after one cycle in these patients, he said.

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*FLEX: First-Line Erbitux in Lung Cancer

Fertility preservation guidelines overlooked by oncologists

Medical Tribune July 2009 P4
David Brill

The majority of US oncologists do not follow recommendations on discussing fertility preservation with cancer patients, a survey shows.

Although seventy nine percent of respondents reported broaching the subject with patients, less than 25 percent referred them to a specialist or provided educational materials.

Just 38 percent were even aware of the existence of the guidelines, issued by ASCO in 2006. [J Clin Oncol 2006 Jun 20;24(18):2917-31]

The findings could prompt the development of new training programs for physicians and nurses, said study author Dr. Gwendolyn Quinn of the H. Lee Moffitt Cancer Center and Research Institute, Miami, US.

“We send patients to get wigs before they lose their hair during chemotherapy. We give medications to prevent nausea. Discussing fertility preservation should be something else that we do early in a patient’s care, rather than waiting until infertility occurs,” she said.

The survey was mailed to 1,979 oncologists – 613 of whom completed it. Those working in gynecological oncology and hematological/medical oncology were the most comfortable with having fertility preservation conversations. Physicians’ views of fertility preservation were also a key factor: those with a favorable attitude towards preservation were nearly five times as likely to discuss the options.

The main reason given for avoiding the discussion was that patients were too ill to delay treatment. Of greater concern, however, was physicians who skipped it because they did not believe that the patient was going to survive their cancer, said Quinn.

“It’s the patient’s right. It’s their choice. They may never pursue it, and some of them can’t afford it, but just to be given that information is important, and it’s perhaps not the role of the physician to make decisions. The guidelines say all patients – they don’t specify the healthiest of patients or the ones most likely to survive,” she said.

Even those who do not survive may wish to review their options for “posthumous parenting,” she added, noting that many US couples cryopreserve embryos or sperm for this purpose before beginning treatment.

Quinn acknowledged, however, that there can be many barriers to discussing fertility preservation, including financial constraints for the patient, or a lack of physician resources in certain geographic areas.

“It’s important to bring it up very near to the time of diagnosis, but we understand that it’s an emotional time,” she said. Future training could move the emphasis towards nurses, who may be better placed to have an in-depth discussion with the patient, she added.

Gemcitabine improves safety for adjuvant pancreatic cancer therapy

Medical Tribune July 2009 P8
David Brill

Gemcitabine is a safer option than 5-fluorouracil/folinic acid (5-FU/FA) for the adjuvant treatment of pancreatic cancer, results of a phase III trial suggest.

Investigators from the European Study Group for Pancreatic Cancer (ESPAC) found that there was no difference in survival between the two therapies, but fewer side effects with gemcitabine.

The study included 1,088 patients who were randomized to one of the two therapies following resection of pancreatic ductal adenocarcinoma. It is the largest adjuvant trial ever carried out in this patient population and the first to directly compare gemcitabine against 5-FU/FA in the adjuvant setting, the researchers say.

“This study is important because it shows no difference between these treatments in prolonging survival,” said lead author Professor John Neoptolemos, head of surgery and oncology at the University of Liverpool, UK.

“On the basis of the safety profile, however, this trial shows that gemcitabine is likely to be the preferred adjuvant therapy. We are now also looking at combining the two treatments to see if we get a better response, because the drugs have different mechanisms of action,” he said.

After a median of 34 months follow up, overall survival times were 23.6 months for patients receiving gemcitabine and 23 months for those receiving 5-FU/FA.

Ten percent of 5-FU/FA patients experienced treatment-related hospitalization, compared to 3.5 percent of gemcitabine patients. Other adverse events which were more common in the 5-FU/FA group included stomatitis (10 percent versus 0 percent; P<0.001) and diarrhea (13 percent versus 2 percent; P<0.001). Some gemcitabine patients, conversely, experienced a drop in platelet count which was not seen in the 5-FU/FA group (1.5 percent versus 0 percent; P=0.0034).

Gemcitabine is typically used in the US for the adjuvant treatment of pancreatic cancer, whereas 5-FU/FA is the standard in some parts of Europe. It was previously unclear which treatment offered a better prognosis.

The trial, known as ESPAC-3, included patients from 16 countries, who were randomized between 11 July 2000 and 12 Jan 2007. Ages ranged from 31 to 85, with a median of 63.

The results will also help to reinforce the design of the upcoming ESPAC-4 trial, added Neoptolemos. The study is set to compare gemcitabine alone against gemcitabine plus capecitabine – a prodrug which is converted to 5-FU in tumors.

No change needed for anal cancer treatment

Medical Tribune July 2009 P8

David Brill

Radiotherapy combined with 5-fluorouacil (5-FU) and mitomycin-C should remain the standard of care for anal cancer, say UK investigators.

Pull quote: “We recommend that radiotherapy with 5-FU and mitomycin-C remains the standard of care for this condition.”Results of the largest-ever trial for anal cancer showed no benefit from switching mitomycin-C for cisplatin, or from adding maintenance chemotherapy to the regimen.

The Second UK Phase III Anal Cancer Trial (ACT II) included 940 patients (median age 58), followed up for a median of 3 years. Those who relapsed or failed to respond to therapy were treated with surgery.

The results of the trial provide good news, despite the lack of benefit shown by the alternative treatment regimens, said lead investigator Dr. Roger James, a consultant radiation oncologist at Maidstone Hospital, Kent, UK.

“Overall the outcome for patients in this study is excellent, with a 95 percent complete response rate at 6 months and an 85 percent survival at 3 years. These are very good results relative to the international trials published so far. We recommend that radiotherapy with 5-FU and mitomycin-C remains the standard of care for this condition,” he said.

Patients were recruited from 2001 to 2008. All were given radiotherapy and 5-FU, and were randomized to receive either additional mitomycin-C or cisplatin. They were then further randomized: half received an extra round of maintenance chemotherapy, comprising two cycles of cisplatin and 5-FU at weeks 11 and 14, and half did not.

Six-month response rates were 94.5 percent for mitomycin-C and 95.4 percent for cisplatin (P=0.53). Non-hematological toxicity was comparable between the groups, affecting 60.2 percent of mitomycin-C patients, compared to 64.6 percent of cisplatin patients (P=0.17). There was, however, more hematological toxicity in the mitomycin-C group (24.7 percent) compared to the cisplatin group (13.4 percent; P<0.001).>

Maintenance chemotherapy had no impact on 3-year recurrence-free survival rates, which were 75 percent for both groups. Overall survival at 3 years was also not significantly different between those who received maintenance therapy (85 percent) and those who didn’t (84 percent).

The ACT II trial results bring another blow to hopes that cisplatin would prove beneficial in anal cancer. Early data had shown anal tumors to be sensitive to a combination of cisplatin and fluorouacil, but a trial of 682 patients, published last year, found that it offered no survival benefits over mitomycin-based therapy. Moreover, cisplatin-treated patients were almost twice as likely to undergo colostomy as those treated with mitomycin (19 percent versus 10 percent; P=0.02), the US Gastrointestinal Intergroup trial Radiation Therapy Oncology Group reported. [JAMA. 2008;299(16):1914-1921]