Fortune highlighted Regeneron for its ability to do drug discovery for much less. To quote from their article here are the costs for drug development by some of the Big Pharma:
Merck : $5.5 Billion per drug
Pfizer: $7.8 Billion
Sanofi: $10 Billion
Average for other Pharma: $4.3 Billion
Regeneron: $0.75 Billion
There may be some fudging and accounting dependent upon how each of the companies account for their development costs but they are still very high and would generalize that it is almost impossible for other companies to do drug discovery but the true number may not be so high.
The article does not give any clues on what worked but the interview does point out that their thinking was long term and very different from the other companies who are very dependent on the perception of the stock market.