Novel Chemoprotective Therapies Under Investigation

Hope S. Rugo, MD, FASCO: The plinabulin data that we’ve discussed has led to an accelerated review by the FDA. It’s always nice to get that because you get a quicker timeframe to decide whether it has met the criteria for approval. But there are a lot of unmet needs in regard to CIN [chemotherapy-induced neutropenia] and new different agents that are also being used for treating or preventing neutropenia. Bill, can you tell us a little bit about those?

William J. Gradishar, MD: Refresh my memory before I start spewing. What was my answer to this one?

Hope S. Rugo, MD, FASCO: The unmet needs, it’s your call, the ongoing trials and new developments, such as trilaciclib, which is approved in small cell lung cancer. There is also this agent, ALRN-6924, which is a peptide drug that inhibits MDMX and MDM2. There are not many other ones.

William J. Gradishar, MD: I’ll just mention that there are other drugs in development.

Hope S. Rugo, MD, FASCO: Specifically call out trilaciclib, because it is approved.

William J. Gradishar, MD: I think this is still an area that’s ripe for investigation. We have all acknowledged during our discussion that as we develop more effective therapies, it is inevitable that we also uncover new toxicities. Supporting blood counts, specifically neutropenia, or preventing neutropenia, continues to be a focus of oncologists. There are other drugs, not only plinabulin, including one recently approved for small cell lung cancer, trilaciclib, which is being investigated in the same area of need. Other compounds are being investigated, including one that goes by the acronym of ALRN-6924, which is a peptide that may also have a similar effect on preventing neutropenia. I think there are a number of agents in this arena. Plinabulin seems very promising, and we’ll just have to see how this plays out with longer follow-up.

Hope S. Rugo, MD, FASCO: It’s interesting that both trilaciclib, which has now gotten approval, and plinabulin, which has phase 3 data, are drugs being used for neutropenia and to try to improve outcomes. Trilaciclib is in a phase 3 trial in triple-negative metastatic breast cancer to try to improve outcome based on encouraging phase 2 data, but it showed this improvement in bone marrow tolerability, reducing neutropenia enough to lead to regulatory approval in small cell lung cancer. But it didn’t show the same effect in breast cancer with a different chemotherapy backbone.

It’s intriguing that these drugs may work differently based on the kind of chemotherapy backbone we have as well.

Transcript edited for clarity.