START trial will show whether therapeutic vaccine Stimuvax (BLP25 liposome vaccine) has potential to extend lung cancer survival beyond 5 years

Of all cancers, non-small cell lung cancer (NSCLC) represents one of the greatest unmet needs for an effective and life-prolonging treatment. The condition, which accounts for 85% of all lung cancers - roughly 1.4 million worldwide each year - is rarely diagnosed at its earliest and most potentially curable stage when it is amenable to surgical resection. Most patients are diagnosed when the tumour has already advanced to stage III, where it has invaded the chest tissues or mediastinal lymph nodes and is inoperable, or to stage IV where it has spread to other organ sites. Around 30% are diagnosed at stage III and 40% at stage IV. Both stages carry a poor prognosis. From stage III, and following chemo and radiotherapy treatment, median survival has been at best only between 13 and 18 months.

Yet later this summer at the 13th World Conference on Lung Cancer in San Francisco, a leading researcher will report on a group of NSCLC patients who are still surviving up to eight years on from a Stage III diagnosis. Dr Charles Butts of University of Alberta, Edmonton, Canada, will reveal updated survival information on a small phase II clinical trial of 171 patients begun in 1998 investigating Stimuvax, an experimental therapeutic lung cancer vaccine (formerly known as BLP-25). Overall, the trial showed a survival benefit of a few months for patients randomised to receive the vaccine compared to best supportive care alone. But it also showed that a subset of patients with Stage IIIb locoregional (LR) disease did particularly well.

When 3-year survival data from the study were presented at the International Association for the Study of Lung Cancer congress in Seoul, South Korea, in 2007 they showed that of patients in this subset, those exposed to Stimuvax had a median survival of 30.6 months compared to 13.3 months if they did not receive the vaccine. Some of these patients are still alive today in 2009, almost 8 years on from starting Stimuvax. This week Dr Butt's reported on the long-term safety of the vaccine among patients using it for over two years at the American Society of Clinical Oncology (ASCO) meeting in Orlando, USA. Only minor side effects were reported, the most frequent being injection-site reactions and cough. The number of patients exposed to the vaccine was very small so no conclusions can be drawn from the research and no statistical significance can be attached to the promising results seen in this group of survivors. However, such was the promise shown in the phase II trial that a much larger phase III trial START (Stimulating Targeted Antigenic Responses To NSCLC) is now investigating the vaccine in many more patients - over 1300 in fact, all with Stage III NSCLC - and should give a definitive answer as to whether or not it really can improve chances of long-term survival for patients at this stage of disease (see link at end of this article for more information).

Normally, only 5 to 7% of Stage IIIb lung cancer patients achieve five-year survival but even patients in the control arm of the phase II Stimuvax study fared better than expected - a well-recognised bonus of clinical trial participation. The phase III START trial is currently recruiting patients with Stage IIIa or IIIb LR NSCLC who have already undergone, and responded to, chemotherapy and radiotherapy given at least a month earlier, or who have stable disease. The 5-year survival rate for such patients would normally be in the range of 15 to 20%. Over 250 centres in 30 countries are participating and the study should begin fielding results in a couple of years.

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