Karyopharm’s blood cancer drug Xpovio has picked up its second U.S. indication, opening up another market before the all-important FDA decision earlier in multiple myeloma.
The FDA has granted Xpovio accelerated approval for the treatment of relapsed or refractory diffuse large B-cell lymphoma (DLBCL) after at least two lines of therapy, Karyopharm said Monday.
“This approval marks the first for an oral agent for patients with previously treated DLBCL and the first approval of any single drug for this highly aggressive type of lymphoma,” Sharon Shacham, president and chief scientific officer of Karyopharm, said in a statement.
It’s still a relatively small market for the first-in-class SINE compound, with SVB Leerink analyst Jonathan Chang pegging the indication’s peak sales in 2028 at $150 million. RBC Capital Markets’ Brian Abrahams, meanwhile, figures it could reach $192 million by that time.
Regulators based the green light on data from the phase 2b Sadal trial, in which the drug triggered a response in 29% of 134 previously treated relapsed/refractory DLBCL patients after a median follow-up of 14.8 months. The drug deterred cancer for at least three months in 56% of responders, and 15% were still responding after 12 months.
Aiming to turn the conditional nod into a full one, Karyopharm will run a confirmatory phase 2/3 study dubbed XPORT-DLBCL-030. The study will combine Xpovio with the so-called R-GDP regimen that includes Roche’s Rituxan, chemotherapy gemcitabine, steroid dexamethasone and platinum chemo.
Karyopharm is immediately rolling out Xpovio in the new indication with its 70 existing sales reps, “which should help limit additional expense requirements,” Abrahams noted in a Monday memo to clients.
Xpovio nabbed its first FDA nod in mid-2019 for late-line multiple myeloma. In the first quarter, the drug racked up $16.1 million in the U.S., coming in below the Street’s expectations of $21.5 million. Management attributed the disappointment to fewer-than-expected new patient starts due to COVID-19 and predicted “slightly higher” sales in the second quarter.
Both late-line myeloma and third-line DLBCL are small markets. The “larger inflection” lies in potential expansion into second-line myeloma, Abrahams said. At the recent American Society of Clinical Oncology virtual meeting, Karyopharm reported that a combination of Xpovio, Takeda’s Velcade once-weekly and dexamethasone significantly cut the risk of disease progression or death by 47% compared with twice-weekly Velcade plus dexamethasone in previously treated myeloma patients. The company filed an application for the indication to the FDA in May.