ORLANDO – Eli Lilly was the last company to bring to market a so-called BTK inhibitor for leukemia and lymphoma. But study results revealed Sunday show Lilly’s medicine may be more effective — and potentially safer — than the oldest drug in its class. 

The data come from a study testing Lilly’s Jaypirca directly against AbbVie and Johnson & Johnson’s Imbruvica. Early results presented at the American Society of Hematology meeting suggest Jaypirca helped induce responses in more people with chronic lymphocytic leukemia or small lymphocytic lymphoma than Imbruvica. More definitive measures of impact — such as effects on disease progression and survival — are pointing in Jaypirca’s favor as well, though additional follow-up testing is needed to confirm those benefits.

The results could be crucial in helping Lilly boost sales of Jaypirca as Imbruvica, which was launched in 2013 and has since been a regular blockbuster, approaches the end of its patent life. J&J and AbbVie reported combined net Imbruvica revenue of more than $4 billion in the first nine months of the year, compared to only $358 million for Jaypirca. But Imbruvica’s sales are declining, as competition is growing from drugs like AstraZeneca’s Calquence and BeOne Medicines’ Brukinsa, both of which are associated with fewer severe side effects. 

Lilly hopes to make similar inroads with Jaypirca. The drug was initially approved for use in CLL or SLL patients who had previously received two treatments. Last week, though, Jaypirca was cleared for use earlier, in people whose disease has progressed after a BTK inhibitor. Its initial “conditional” approval was converted into a traditional nod, too.

With the Bruin-CLL-314 trial, Lilly is trying to position Jaypirca even earlier and show its drug is at least as good as Imbruvica in the process. The study is testing Jaypirca against Imbruvica in people who haven’t received any treatments for their cancer, or who have progressed on one treatment line. Lilly is initially measuring response rates, but also hopes the trial will show that people who get Jaypirca will survive longer without their disease getting worse.

Early data disclosed at ASH indicate Jaypirca is hitting those goals. When measuring responses across all 662 study participants, 87% of enrollees who got Jaypirca responded to treatment compared with 79% of those who got Imbruvica, a difference that was statistically significant for showing “non-inferiority.” Most of the responses were considered “partial,” meaning treatment reduced, but didn’t eliminate, symptoms and biological markers of disease.

In people whose disease had progressed on, didn’t respond to a previous treatment, Jaypirca also proved non-inferior, with 84% of people responding compared to 75% of those who got Imbruvica. Among participants who hadn’t yet been treated, 93% of people who got Jaypirca responded versus 86% of Imbruvica recipients, but that difference wasn’t deemed statistical proof of “non-inferiority.”

Jaypirca is also showing signs of delaying disease progression or death, although the analysis conducted so far was considered an interim look, said trial investigator Jennifer Woyach, the co-leader of the leukemia and hematologic malignancies program at The Ohio State University Comprehensive Cancer Center, in a press conference at ASH. Jaypirca reduced the relative risk of progression or death 43% in the broad population, with the benefits more pronounced in people who had never received treatment than who had progressed or didn’t respond to earlier care.

People taking the two drugs had similar rates of common side effects in cancer treatment such as reduced white blood cell counts, anemia, infections or gastrointestinal problems. However, Jaypirca was associated with lower rates of hypertension and irregular heartbeat, an issue that has hurt Imbruvica’s uptake.

The data should “potentially allow pirtobrutinib to be used in earlier lines of therapy,” Woyach said, using Jaypirca’s scientific name.

“I think longer follow up and a continued look at the safety profile is going to be needed to really decide which groups of patients are most appropriate to receive pirtobrutinib in the frontline setting,” she said. “I do think that potentially patients who are older and those that are more frail could benefit from this drug, given the excellent safety profile.”