The two firms announced the results of two recently completed Phase II clinical trials during the World Conference on Lung Cancer in Seoul, South Korea this week.
Canada-based Biomira has opted for the more challenging approach developing a vaccine while Antisoma stuck to the 'old-fashioned' small molecule way. No cancer vaccine has reached the market so far.
Biomira said three-year survival results from a randomised Phase II study of its Stimuvax vaccine suggest that the drug, combined with chemotherapy, may provide survival benefits to patients with unresectable stage IIIB NSCLC - the most common form of lung cancer - compared to patients receiving chemotherapy alone.
The study, which involved 171 patients, showed that more than twice as many patients were still alive at three years in the group receiving Stimuvax compared to chemotherapy alone (49 per cent vs 27 per cent), representing a 45 per cent reduction in mortality.
Subjects with stage IIIB disease who received Stimuvax in this trial also experienced a 17.3 month difference in median survival compared with patients receiving chemotherapy alone (30.6 months vs. 13.3 months, respectively).
Patients treated with the drug only reported mild to moderate side effects limited to flu-like symptoms, gastro-intestinal disturbances and mild injection-site reactions, said Biomira.
The vaccine was granted fast-track status in September 2004 by the US Food and Drug Administration (FDA) and Merck KGaA has the exclusive worldwide licensing rights from Biomira. Stimuvax is being developed in Europe by the German firm and in the US by its subsidiary, EMD Serono.
Merck has initiated patient recruitment for a Phase III trial, START, which is a multi-centre, randomised, double-blind, placebo-controlled study that will evaluate patients with unresectable stage IIIA or IIIB NSCLC who have had a response or stable disease after at least two cycles of platinum-based chemo-radiotherapy. The study will involve more than 1,300 patients in approximately 30 countries, the company said.
Meanwhile, UK-based Antisoma is playing catch up and has also released positive survival data from a Phase II trial of its ASA404 drug candidate combined with chemotherapy.
This single-arm trial tested an 1800 mg/m2 dose of ASA404 in combination with carboplatin and paclitaxel chemotherapy in 31 patients with NSCLC.
This trial was conducted as an extension to an earlier, randomised study of ASA404 for the same indication. The aim was to evaluate the activity and safety of a higher dose of ASA404 than that used in the other phase II trial.
The latest study showed that median survival was 14.9 months while the median time to tumour progression was 5.5 months. Addition of ASA404 to chemotherapy was also well tolerated, the company said.
In the previous trial, patients who received a 1200 mg/m2 dose of ASA404 combined with chemotherapy had a median survival of 14.0 months whereas patients who received chemotherapy alone had a median survival of 8.8 months, a 60 per cent difference. Time to tumour progression was 5.4 months with ASA404 and 4.4 months with chemotherapy alone.
Although results between the latest trial and the previous study cannot directly be compared, the data released this week give "extra corroboration that ASA404 combined with chemotherapy improve patient survival, as both studies involved the same type of patients who were at the same stage of disease", Antisoma spokesperson Daniel Elger told Biopharma-Reporter.com.
Antisoma's partner, Novartis, plans to start enrolment of patients into a phase III trial in early 2008. The Swiss giant drug maker acquired the worldwide rights for the drug in April in a deal worth $890m (€654m).
Under the terms of the agreement, Antisoma has the option to co-market ASA404 in the US, should the drug reach the market, said Elger.
This is a strategic move for Antisoma as it will get the support of Novartis to put a sales force in place in the US with the freedom to use it to later sell its own drugs, added Elger.
According to the World Health Organisation, there are more than 1.2m cases worldwide of lung and bronchial cancer each year and the American Cancer Society (ACS) estimates that around 213,000 people will be diagnosed with lung cancer in the United States during 2007.
The US National Cancer Institute reports NSCLC accounts for more than 80 per cent of all lung cancers.
