NEW YORK – Pfizer on Thursday highlighted that US sales of its CDK4/6 inhibitor Ibrance (palbociclib) returned to growth after more than a year of revenue declines.
The sales growth in the US occurred despite declines in other markets and amid competition from Kisqali (ribociclib), Novartis' CDK4/6 inhibitor, which boasted double-digit sales growth in Q2 2022. Kisqali is faring well on the market partly because in the MONALEESA-2 trial, Novartis' drug plus letrozole improved overall survival in hormone receptor-positive, HER2-negative advanced breast cancer patients. Pfizer's drug in combination with letrozole, however, did not show a survival benefit in estrogen receptor-positive, HER2-negative advanced breast cancer.
In Q2 2022, revenues from the oncology segment overall dipped 2 percent to $3.09 billion from $3.15 billion in Q2 2021. Globally, revenues for Ibrance, Pfizer's top-selling drug in the oncology segment, fell 6 percent to $1.32 billion from $1.40 billion in the prior year. International sales of Ibrance fell 17 percent to $452 million from $542 million in the year-ago quarter.
However, in the US, Ibrance sales increased 1 percent to $868 million from $862 million in Q2 2021. Pfizer CEO Albert Bourla noted on a call to discuss the financial results that Ibrance returned to US growth "despite the continued increase in the proportion of patients accessing Ibrance through the assistance program." Bourla also said the total volume dispensed in the US increased 3 percent from Q2 2021.
"This marks the first quarterly revenue increase in the US since the fourth quarter of 2020, which is an encouraging sign," he said.
For the past several quarters, Pfizer has attributed the US decline in Ibrance sales to increased use of its patient assistance program and a decline in new patient starts due to the COVID-19 pandemic.
Angela Hwang, group president for Pfizer's biopharmaceuticals group, said on the call that the company still sees growth potential for the drug "even though Ibrance is a mature brand." She noted that Ibrance has 74 percent market share across all patients in the first-line metastatic breast cancer setting.
"It demonstrates the tremendous experience that physicians and patients have and the confidence they have in Ibrance, despite new competition," Hwang said. "Where the growth will come from is … growth in the CDK class; growth from the recovery of new patient starts, which have not recovered to the levels prior to the pandemic; as well as the stabilization of the [patient assistance program]."
Hwang said the CDK4/6 inhibitor class itself has room to grow, with the entire class addressing 54 percent of the breast cancer market in Q2. That market share has increased from the year-ago quarter, when it was 48 percent.
"This means the majority of the time CDK4/6 [inhibitors] are not being used," she said. "All of us in this class need to focus on this as the leading priority, not only to grow the [Ibrance] brand, but also the class."
In the CDK4/6 inhibitor space, there are several drugs for treating hormone receptor-positive, HER2-negative metastatic breast cancer, including Ibrance, Eli Lilly's Verzenio (abemaciclib), and Novartis' Kisqali. In Q2, Kisqali contributed $308 million to Novartis' revenues, up 37 percent from $225 million in Q2 2021, driven partly by the overall survival advantage seen in MONALEESA-2 at the American Society of Clinical Oncology annual meeting in June.
Data presented at the same meeting, however, showed that Ibrance plus letrozole did not significantly improve long-term overall survival as a front-line treatment for patients with estrogen receptor-positive, HER2-negative advanced breast cancer compared to hormone therapy alone. After seven years of follow-up in the Phase III PALOMA-2 trial, the median overall survival was 53.9 months on Ibrance-letrozole versus 51.2 months in the letrozole-placebo arm.
The data prompted experts at the meeting to debate the differences between the three approved CDK4/6 inhibitors, as more long-term survival data is expected from a trial of Verzenio later this year. During the call, Pfizer executives didn't discuss the overall survival data for Ibrance, however.
Beyond Ibrance, Pfizer reported revenue growth for several precision oncology treatments in its portfolio. The firm's second-generation ALK inhibitor for non-small cell lung cancer, Lorbrena (lorlatinib), reported $77 million in global sales compared to $66 million in the prior year, a 16 percent increase. The drug reported double-digit sales growth in both US and international markets.
Lorbrena's growth offsets revenue declines that Pfizer's first-generation ALK inhibitor Xalkori (crizotinib) has been experiencing. During Q2 2022, Xalkori's revenues decreased 2 percent globally to $118 million from $120 million in Q2 2021.
Revenues from the combination of the BRAF inhibitor Braftovi (encorafenib) and MEK inhibitor Mektovi (binimetinib) also grew in Q2. Braftovi-Mektovi is approved in the US as a treatment for BRAF-mutated melanoma, and Braftovi combined with Eli Lilly's Erbitux (cetuximab) is also approved for BRAF-mutated colorectal cancer. Braftovi generated $51 million in Q2 sales, a 20 percent increase from $42 million in Q2 2021. During the same period, Mektovi sales grew 22 percent to $44 million from $36 million in the year-ago quarter.
Overall, Pfizer reported a 47 percent increase in Q2 revenues to $27.74 billion in revenues in Q2 compared to $18.90 billion in the prior year. The revenue was largely driven by sales of its COVID-19 vaccine and treatments.