Background: Targeted therapies have to date not been successful in the treatment of small cell lung cancer (SCLC). This study aimed to assess the therapeutic activity of sunitinib (an oral, multi-targeted tyrosine kinase inhibitor) using positron emission tomography (PET)-computed tomography (CT) imaging as an early indicator of response.
Methods: This was a single-arm phase II study of sunitinib in patients with SCLC who are either chemo naive (extensive disease) or have a 'sensitive' relapse. A loading dose of 150 mg sunitinib was given orally followed by 37.5 mg/d. The primary end-point was disease control rate (DCR) at 8 weeks after the start of treatment and secondary end-points included toxicity of treatment and overall response. PET-CT was carried out at 4 weeks into the treatment. The study was closed early because of low accrual with only 9 of required 48 patients (19%) accrued.
Results: Nine patients were registered, seven females and two males with a median age of 65 years and a median duration of sunitinib treatment of 7.4 weeks. DCR at 8 weeks was achieved in two patients, both of whom went on to long periods of disease control, one patient achieved a partial response which lasted 10 months and a second patient had stable disease (minor shrinkage) which lasted 20 months. One of these patients proved to have an atypical carcinoid tumour at rebiopsy after 10 months. DCR and PET-CT imaging both predicted these responses. Grade III-IV toxicities were encountered during treatment, most commonly neutropenia (n = 3), thrombocytopenia (n = 3) and hypermagnesaemia (n = 2). One toxic death occurred due to bronchial haemorrhage.
Conclusion: This study emphasises the need for alternate study design and end-points for new drug assessment in SCLC. EudraCT number: 2006-002485-19.
Keywords: Phase II study; SCLC; Second-line treatment; Sunitinib; Targeted therapy; Tyrosine kinase inhibitor.
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