Why is cancer drug tamoxifen in short supply in Canada?

This CBC report suggests that the spotty supply of the cancer therapy drug tamoxifen has been caused by manufacturers leaving the market because of downward pressures on the price. It’s apparently about money. Canadian manufacturer, Apotex, told CBC it was fixing production issues. What that means is unclear. The British firm, AstraZeneca, says it expects to be able to meet all demand very soon.