LeonaBio, Inc. Common Stock 12th Annual Cantor Fitzgerald Global Healthcare Conference

Yes. My familiarity goes back almost two decades. I am dating myself. I was an advisor to Pfizer on their program, largely focused on prevention, a PI on 5 of their 11 phase II and III trials. It is a very well-characterized molecule. They deprioritized it after the Wyeth acquisition in 2009. While the drug went through full development for osteoporosis treatment, it was a very potent anti-resorptive. It actually had two phase III trials that showed that it treated urogenital atrophy and decreased new onset breast cancer. It was a remarkable drug for preventive health strategies. Unfortunately, it never really got to see the light of day. Rights were returned to Ligand, and that is when I founded Sermonix and in-licensed it and discovered very coincidentally that it was the most potent molecule against ESR1-mutated cell lines.

That is when we became from a women's health prevention company to a precision oncology company, taking it through phase II studies, showing activity in monotherapy and in combination. Then when the phase III needed to be funded and operationalized, that is when the opportunity to join forces with Mark and Leona materialized.

Yeah. We're thrilled to be the only pure SERM, or selective estrogen receptor modulator, in late-stage development for advanced breast cancer. It's a very crowded SERD space. The reason originally was because these mutations of the estrogen receptor become ligand independent, so logically it made sense to use a protein degrader to eliminate that receptor. What we found was that by binding with high affinity to those mutated receptors and inactivating them, putting them into an inactive conformation, we could do just the same, in fact, potentially better because of lasofoxifene's potency. It's the most potent small molecule. Even though it's not a degrader, it's more potent than all the degraders in development and approved. It also doesn't indiscriminately antagonize healthy estrogen receptors.

Coming from that women's preventive health world, I can certainly tell you that antagonizing estrogen in these women who are suffering from breast cancer can lead to very poor quality of life. So we think we have that unique advantage by not degrading or antagonizing estrogen receptors in the brain, the gut, the urogenital tract, but being a potent antagonist at the breast. It's the best of all possible worlds, and uniquely differentiated from the degraders.