I don't work with biotech companies any more, but am still interested in new drug discovery.
Immune therapy is the hottest area in cancer research today. The drugs are derived from an improving understanding of how cancer cells evade detection and destruction by our immune system. Our immune systems are powerful, so much so that they can kill us if they are too active or attack things that they should not attack. We have various mechanisms to turn off the immune response. Cancer cells can mimic those mechanisms. Immune therapy involves suppressing those mechanisms or engineering immune cells that attack particular forms of cancer even when they are using those mechanisms. A few immune treatments have been approved by the FDA in the past two years. They work really well in some patients and not at all in others. As scientists try to understand what makes one patient respond to a treatment so he lives, and another not respond and die, they have been discovering a relationship with the gut biome.
The gut biome is all the microbes that live in your intestinal organs. We support huge numbers of microbes, and are starting to learn that, far from being dirty parasite to be eliminated, they are essential to our bodies' function. This will be one of the most exciting areas of research in coming decades, in part because it is easy to test hypotheses by transplanting microbes from one patient to another, or initially from one rat to another. The linked article illustrates one recent finding.
https://arstechnica.com/science/2017/11/gut-bacteria-may-make-or-break-your-chances-of-cancer-treatment-working/
I'm interested in seeing how the drug companies approach gut biome research. They need to be able to develop a patented drug. Simply learning how to cure patients won't bring profits, if anyone can do it. For example, there is a microbe called C. Difficile which is a major killer of hospitalized patients. It grows rampant in patients whose gut biome (aka gut flora) has been decimated by antibiotics, leaving C. Difficile with little competition. The conventional treatment for C. Diff is more antibiotics designed to kill C. Diff. These can suppress an outbreak, but leave the gut biome decimated and the patient at risk of re-infection, which often happens since C. Diff is very hard to eradicate from surfaces. Another way to treat C. Diff is to take fecal matter from a healthy person and introduce it into the gut of the patient, prompting his gut biome to rebuild. Since there is no way to patent this treatment or make it into a pharmaceutical, fecal transplants haven't gotten the attention, research, and marketing necessary to make the treatment widely available. If it isn't a drug, there isn't money in it.