Lilly Korea is seeking to reshape Korea’s breast cancer treatment market on the occasion of its winning the sales approval for its Verzenio, a cyclin-dependent kinase (CDK) 4/6 inhibitor, from the Ministry of Food and Drug Safety, the company said Friday.

Professor Sohn Joo-hyuk from Yonsei Cancer Center explains how Verzenio and other CDK 4/6 inhibitor treatment will reshape the breast cancer treatment, during a news conference at Lilly Korea headquarters in downtown Seoul, on Friday.

The ministry approved the drug in combination with an aromatase inhibitor or as a combination therapy with fulvestrant in treating HR+/HER2-progressive or metastatic breast cancer with advanced disease after endocrine therapy in May. Until the approval of Verzenio, Pfizer’s Ibrance had been the only approved CDK 4/6 inhibitor treatment for breast cancer in Korea.

HR+/HER2-progressive cancer accounts for 73 percent of local breast cancer patients, while the five-year relative survival rate, including metastasis breast cancer, is only 38.9 percent.

With the recent emergence of CDK 4/6 inhibitor, the treatment field has taken a new turn. CDK 4/6 inhibitor drugs selectively inhibit the growth of cancer cells by selectively inhibiting CDK. Subsequently, the drug induces the cell cycle to be halted while suppressing CDK4/6, while at the same time killing the breast cancer cells.

“For the past half century, hospitals have used only hormone therapy to treat HR+/HER2-progressive cancer,” Professor Sohn Joo-hyuk from Yonsei Cancer Center said, in a news conference Wednesday. “With the introduction of the CDK 4/6 inhibitors, however, we are looking at a new era in treating breast cancer.”

Professor Sohn noted that in the Monarch3 trial, which confirmed the primary endpoint of Verzenio, the progression-free survival (PFS) time increased to 28.18 months versus the existing aromatase monotherapy (14.76 months). The treatment also increased PFS in comparison with fulvestrant monotherapy (9.2 months) to 16.4 months.

“Patients with liver metastases, high tumor grade, good relapse times, progesterone receptor negative, and non-bone metastases all had a longer PFS when taking Verzenio,” he said. “The drug is also the only CDK 4/6 inhibitor available in Korea that patients can take daily without a break period and can take the medication orally twice a day, regardless of eating meals.”

The results of the metastatic breast cancer study and the recurrence rate and cure of early breast cancer are still in progress and are expected to continue in the future, he said.

Despite such advantages, the company still has some hurdles to overcome, such as reimbursement and safety issues before calling the launch of Verzenio in Korea a success, industry watchers said.

Pfizer’s Ibrance is currently the only CDK 4/6 inhibitor treatment that receives reimbursement for treating postmenopausal women. As anticancer therapies are expensive, it is necessary for the company to receive reimbursement if they want to procure a market share in Korea stably.

There is also the matter of a safety warning raised by Japan’s Health Ministry regarding the drug possible negative impact on the patient’s lungs, the experts said.

Postmarketing surveillance from November to May in Japan showed that 14 patients had severe epileptic lung disease, four of which had a causal relationship with the onset of the disease and the medication.

“We have submitted a report on the side effects in mid-May and are awaiting answers from the local health ministry,” a company spokesperson said.

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