Many countries basically dictate to the drug companies what they can charge. So long as what they dictate is above the *marginal* cost of selling the drug in that country. The drug companies have to recoup their development from the places that don't dictate prices.
If the US were to also dictate prices (and I think they should, but indirectly: require them to sell to the US at the lowest price they sell to any other developed nation) you would see drug prices in the US drop--but drug prices in other countries would rise.
We see the same problem in the US with government-dictated doctor rates. More and more doctors are saying "NO" to Medicare and Medicaid because the rates are often below the marginal cost. The doctors have to make their money on private insurance patients. (Which is also why simply doing Medicare-for-all would be an abysmal failure.)