The present invention relates to medical use of liposomes, more particular the first medical use of sPLA2 hydrolysable liposomes. Such liposomes may be used for targeted delivery of therapeutic agents to cancerous tissue and in such embodiments; the therapeutic agents are typically small molecule antitumor agents. Other aspects of the inventions relates to methods of reducing the side effects of therapeutic agents, e.g. reducing nephrotoxicity, neurotoxicity and gastrointestinal toxicity of a therapeutic agent. Yet another aspect of the present invention relate to methods of prolonging the therapeutic effect of a therapeutic agent.