$TRIL A drug has to go through 3 phases of clinical studies before a regulatory body will review the new drug application (NDA). A successful phase 1 means you have enough evidence to move forward to phase 2. As you up the phases (trials), the more patients are involved. Patient selection becomes a problem, and this is where a lot of drug development goes into limbo land - not enough patients to try on. Also, real-world variation starts to kick in. Meaning, the researchers begin to more clearly understand the efficacy, effectiveness, and potential adverse event. TRIL news appears to be good for the war on cancer. The cost of research goes up exponentially given the expanded study sites along with increasing patient size. It takes BILLIONS to get a drug to market.