Published online by Cambridge University Press: 01 August 2014
1. Vinblastine (VLB) and vincristine (VCR) are both naturally occurring alkaloids derived from the flowering periwinkle plant, Vinca rosea, Linn.
2. Both drugs have large molecules and are very similar in chemical structure. They differ only in that VLB has a methyl group (-CH3) while VCR has a formyl group (-CHO) attached to one of the nitrogen atoms in the molecule.
3. In spite of this chemical similarity, VLB and VCR differ greatly in the types of malignancy against which they are effective, their toxicities, and their potencies.
4. With these differences in mind, it appeared logical to produce more alkaloids of the series by modifying one of the side chains of VLB.
5. Vinglycinate sulfate (VGL), the first of these semisynthetic VLB derivatives to undergo clinical trial, has proved useful in the treatment of some patients with malignant disease. There was no cross-resistance between VGL and its parent substance, VLB, or with VCR.