NEW YORK – Novartis on Tuesday reported strong second quarter sales for Kisqali (ribociclib) driven in part by data readouts at the American Society of Clinical Oncology's annual meeting, reinforcing the CDK4/6 inhibitor's overall survival benefit in hormone receptor-positive, HER2-negative advanced breast cancer.
Kisqali's Q2 sales growth may spell trouble for its main competitor, Pfizer's CDK4/6 inhibitor Ibrance (palbociclib).
Kisqali was Novartis' only precision oncology product to achieve double-digit sales growth versus the prior year's second quarter. In Q2 2022, Kisqali sales were $308 million, up 37 percent from $225 million in Q2 2021.
"We see [Kisqali] as a brand that, given its recent data releases, is really coming into a strong growth profile," Novartis CEO Vas Narasimhan said during a call Tuesday morning to discuss the company's Q2 financial results.
Kisqali sales grew against the backdrop of a sub-par sales quarter overall for the Basel, Switzerland-based drugmaker, which reported overall revenues dipped 1 percent to $12.78 billion in Q2 2022 from $12.96 billion in Q2 2021.
Outperforming CDK4/6 inhibitor competition
Fresh evidence on Kisqali in recent months has bolstered sales of the drug in the US and abroad. At ASCO's annual meeting in June, Novartis presented updated data from the Phase III MONALEESA-2 study showing that Kisqali plus the aromatase inhibitor letrozole demonstrated an overall survival benefit versus placebo plus letrozole in the first-line treatment setting for hormone receptor-positive, HER2-negative metastatic breast cancer. Patients with the CDK4/6 inhibitor combination lived for a median of 63.9 months versus 51.4 months with just letrozole.
Taken together with results from the MONALEESA-3 and MONALEESA-7 trials, Narasimhan noted that Kisqali's overall survival benefit in the first-line treatment setting for metastatic breast cancer has been consistent regardless of patients' menopausal status, the specific hormone therapy it's combined with, or dose modifications. The drug also appears to benefit patients treated with prior CDK4/6 inhibitors.
"We think this dataset is part of the reason we're seeing real growth acceleration behind Kisqali," Narasimhan said. He further proposed that Kisqali's advantage versus other CDK4/6 inhibitors may be related to the fact that CDK4 is the more important target, and the Novartis drug hits CDK4 eight times harder than it hits CDK6.
Kisqali has had the US Food and Drug Administration's approval as first-line treatment combined with hormone therapy in this hormone receptor-positive, HER2-negative metastatic breast cancer patient population since 2017. As such, the sales growth isn't a reflection of regulatory action so much as the landscape for CDK4/6 inhibitors shifting based on emerging long-term overall survival data.
The positive MONALEESA data sharply contrasts with the recent poor trial performance for Pfizer's Ibrance. In June, Pfizer reported that Ibrance plus letrozole did not result in a statistically significant long-term overall survival benefit versus placebo and letrozole among estrogen receptor-positive, HER2-negative advanced breast cancer patients.
"We're starting to see a trend in [new-to-brand prescriptions for Kisqali] in the first half of the year versus the competition in the metastatic setting, and that comes primarily from Ibrance," Narasimhan said. He still sees a lot of opportunity for growth with Kisqali, since sales only recently returned to where they had been before the COVID-19 pandemic.
Eli Lilly also has a CDK4/6 inhibitor, Verzenio (abemaciclib), which is approved in the same metastatic patient population. The long-term overall survival data for Verzenio and letrozole versus placebo and letrozole in the Phase III MONARCH 3 study are not yet available, so it's unclear how Kisqali and Verzenio compare on this endpoint.
In a panel discussion at the ASCO meeting, oncologists suggested that the drugs that fall into the CDK4/6 inhibitor category are actually quite different in terms of their structures, and this should be considered when making treatment decisions.
Anticipation builds for adjuvant data
As Kisqali sales grow, driven by the landscape for first-line metastatic breast cancer, the jury is still out in terms of whether the drug will perform as well as an adjuvant treatment for early-stage hormone receptor-positive, HER2-negative breast cancer. The Phase III NATALEE study, which Narasimhan said is now fully enrolled, is designed to answer this question, pitting Kisqali plus endocrine therapy against endocrine therapy alone in the adjuvant treatment setting for stage II or III breast cancer. As of now, Lilly's Verzenio has a leg up. That CDK4/6 inhibiting drug is FDA approved with endocrine therapy for hormone receptor-positive, HER2-negative, node-positive early breast cancer patients who have a high risk of disease recurrence and a Ki-67 score of at least 20 percent as determined by an FDA-approved test. Pfizer's Ibrance, of note, did not benefit patients in the adjuvant setting in the Phase III PALLAS trial, which was discontinued accordingly.
Looking ahead, Narasimhan said that Novartis will report the primary analysis from the NATALEE trial once there are 500 invasive disease-free survival events, data he expects will be available by the end of 2023. In the meantime, he said that there will be two interim analyses conducted at 350 and 425 invasive disease-free survival events. The trial has yet to reach either of those cutoffs, but Narasimhan said he expects those readouts "in the coming quarters" and will share relevant updates as they're available.