Well, sure, if the “lifetime” in question is thirty or forty or fifty years. With most cancers, it’s sort of kind of not. You’re also leaving out two more factors that would increase the profit of a pharma company that created a true cure - market share and R&D costs.
Let’s play a game with numbers (some of these articles are a bit old, but usable for illustrative purposes).
The median overall survival (time from date of first treatment to date of death from any cause) in metastatic colorectal cancer among patients treated with 5-fluorouracil, leucovorin, and irinotecan - basically chemotherapy - is 15.6 months. Adding the fairly new agent bevacizumab (Avastin) to this regimen extended overall survival to 20.3 months in this population. (cite)
Now, typically, treatment with bevacizumab would be withdrawn once the cancer progresses - ie, once the treatment no longer works - so in reality a typical metastatic CRC patient is going to be receiving bevacizumab for less than 20 months, but let’s go with 20 months. So your median mCRC patient gets 20 months of therapy with bevacizumab.
Genentech charges about $4400/month for Avastin. So, from your typical patient with mCRC, they are getting approximately $88,000 before that patient dies (again, really less, since in most cases the patient will progress).
Very approximately, 150,000 colorectal cancer cases are diagnosed each year, with about 20% of those being metastatic at diagnosis. So, 30,000 patients present as mCRC and might receive bevacizumab for these purposes. But not all will. Because bevacizumab is not curative, an individual oncologist might decide to use an alternative agent, or radiation therapy, or whatever. So let’s say that of those 30,000, 20,000 receive bevacizumab for 20 months median.
That means that under the current system, Genentech would net around $1.76 billion per year of new cancer cases (all numbers estimated, again).
Now suppose someone at Genentech actually did have access to a super-secret cure for metastatic CRC (we’ll call it MAGICDRUG). Let’s say they price it reasonably - at $75,000 per patient for a full course, meaning that your typical patient is actually paying less than for a standard course of bevacizumab.
But this is a cure. There is no reason not to take MAGICDRUG if you have metastatic CRC. So all 30,000 patients diagnosed with this condition will take MAGICDRUG at $75,000 each. Net income per year of new diagnoses: $2.25 billion. And of course, in real life, MAGICDRUG would be priced closer to $100,000 for a full course, thus dramatically increasing its profitability.
So it would in fact be considerably more profitable to create a cure than to sell a maintainence drug.
Plus, and even more significantly, once you’ve created your cure, you no longer need to research new treatments for colorectal cancer. Your R&D budget can be slashed, or else the funds can be turned toward other disease states.
Now tell me this. Why would Genentech continue to pour millions upon millions of dollars into researching new agents that might grant two or three extra months (at best!) on top of bevacizumab (thus resulting in an extra $12,000 or so per patient), when they could control the entire market, cut their development costs, and make much more money using that cure on which they are hypothetically sitting?
Ok, yes, I am evil this morning.