As if cancer patients don't have enough to worry about, they often have to go through torture in the form of nausea and vomiting. This is not merely an "inconvenience." Depending on the regimen (drug combination) they're receiving, the chemotherapy-induced nausea and vomiting (CINV) experience can be severe enough that patients often discontinue treatment, perhaps even at the expense of saving their lives.
But now, with the FDA's approval this week of Varubi, most cancer patients receiving this treatment will experience no nausea or vomiting. But first, some background.
Zofran (ondansetron) the first game changer was approved by the FDA in 1991. Most oncologists agreed it revolutionized cancer chemotherapy by providing protection against CINV that was never achieved before.
Even against the most highly emetogenic (vomit inducing) regimens, such as platinum-based drugs, many patients were protected. When combined with dexamethasone (an anti-inflammatory steroid) Zofran controlled CINV about 75 percent of the time. This was unprecedented.
Zofran works by blocking the 5-HT3 subtype of serotonin receptors (5-HT is short for 5-hydroxytryptamine, aka serotonin). These are found in the brain and in the stomach, and are responsible for a significant percentage of CINV.
As I wrote last June, this is a significant drawback to Zofran and other antiemetic drugs. There are two components of CINV: an acute phase, and a delayed phase, which begins between one and five days following chemo. While Zofran works quite well for the former, it does not for the latter.
Delayed-phase CINV became treatable last year when the FDA approved Akynzeo. The drug is a combination of netupitant the first member of a new class of drugs called neurokinin-1 (NK1) receptor antagonists and palonosetron, a more potent version of Zofran. The combination was highly effective in treating both phases of CINV. This is because NK1 receptor antagonists operate by a different mechanism. When they are combined with a Zofran-like drug and dexamethasone, the mixture is more effective.
Things got even better this week, when Varubi a combination of palonosetron and rolapitant, a different NK1 receptor antagonist received FDA approval. Its main advantage is that it hangs around for a long time (meaning half of it remains in the blood after a week), which is exactly what you'd want for a drug to treat delayed-phase CINV.
Varubi will be sold by Tesaro Inc., a Massachusetts-based oncology specialty biotech. CEO Lonnie Moulder says, "because 5HT3 receptor antagonists are so effective in the early phase of nausea and vomiting, the greatest need that exists today is for what we call the delayed phase, days two through five [after chemo]. The half-life of Varubi, approximately seven days, matches up very nicely with that. Given ahead of chemo, the drug protects the patient over the full five-day at-risk period."
We hope you never need to go through cancer chemotherapy. But if you do, your life will be substantially better because of discoveries like these.