Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Vesanoid (Roche Products) 10 mg capsules
Indication: promyelocytic leukaemia
Tretinoin is aretinoid closely related to vitamin A. It is known to increase the proliferation of epidermal cells and so has been used for the treatment of acne. In vitro it can also induce the differentiation of leukaemic cells.
Promyelocytic leukaemia is associated with a translocation on chromosome 17. This translocation is in the region of a retinoic acid receptor, which may be the target for tretinoin. As conventional chemotherapy for this acute leukaemia has a high mortality and morbidity, tretinoin offers an alternative.
The drug is given twice a day for 30-90 days. This will induce remission in a majority of patients. After complete remission, a course of consolidation chemotherapy should be given.
Although the mortality associated with tretinoin may be less than for conventional treatment, it can cause serious adverse effects. Up to a quarter of patients may develop a hyperleucocytosis syndrome. The syndrome can present with fever and dyspnoea. There may be pleural effusions, pulmonary infiltrates, hypotension and respiratory failure. The syndrome can be fatal, but will often respond to high doses of steroids. Other adverse effects include rashes, oedema, hearing disorders, bone pain, nausea and vomiting.
Tretinoin is effective at inducing complete remissions inpromyelocytic leukaemia, but its effect is short-lived. At present, it is uncertain if a better outcome is achieved by giving chemotherapy after tretinoin or giving the drugs concurrently.
