Sanders, along with co-sponsors Elizabeth Warren and Robert Casey, offered an amendment... that would have allowed for importation of drugs from FDA-approved facilities in Canada...
Once again, Democratic discipline broke down. The amendment this time was beaten in committee, 13-10. Two Democrats, Patty Murray and Michael Bennet, both of whom accept a lot of pharmaceutical money, voted no.
Interestingly, two Republicans from states bordering Canada who voted for almost exactly the same measure earlier in the year - Murkowski of Alaska and Susan Collins of Maine - now voted no as well.
This often seems to happen with controversial bills. The math will allow a large-ish number of members to cast a vote in favor of a popular policy disliked by industry, but if there's any danger of it actually passing, there will suddenly be defectors or converts. The political damage is limited to just a few poor souls who have to wear the unpopular vote.
This is why you should never trust a politician like Cory Booker who tells you that he supports your issue but couldn't vote for this particular version of it because of some minor (bullshit) flaw.