Jazz’s HER2 Bispecific Gets FDA Green Light

A bispecific antibody has emerged in the HER2 arena, exhibiting a different profile compared to conventional treatments and presenting a potential threat to AstraZeneca and Daiichi Sankyo’s leading antibody-drug combination, Enhertu.
Jazz Pharmaceuticals’ zanidatamab has received FDA expedited clearance for people with recently treated HER2-positive biliary tract cancer. The medication, administered by intravenous infusion biweekly, will be marketed under the trade name Ziihera.
Focusing on bigger market prospects in HER2-positive gastric and breast cancer, Jazz has estimated Ziihera’s peak yearly sales potential to exceed $2 billion, as stated by CEO Bruce Cozadd in an interview prior to Wednesday’s FDA approval.

In 2022, Jazz acquired specific ex-Asian rights to Ziihera via a licensing deal with Zymeworks, which included an initial payment of $50 million and prospective payments totaling up to $1.76 billion. Zymeworks will receive a $25 million bonus payment due to the FDA approval.
Jazz was drawn to Ziihera’s bispecific framework when finalizing that agreement. The medication targets two HER2 epitopes, which are also individually addressed by Roche’s successful HER2 antibodies, Herceptin and Perjeta. In contrast to the Herceptin and Perjeta combo, Ziihera’s bispecific binding induces distinctive clustering of the HER2 receptor, thereby more effectively disrupting the signaling of the oncogenic driver, as explained by Jazz’s R&D chief, Rob Iannone, M.D., in an interview.
Ziihera caused a tumor response in 52 out of 62 patients with HER2-positive biliary tract cancer who had previously received treatment for the disease. Among them, two patients (3.2%) experienced a full response in the phase 2b HERIZON-BTC-01 study. The median response length was 14.9 months.
In June, Jazz announced that Ziihera enabled HER2-positive individuals in the midstage trial to achieve a median survival of 15.5 months. This data point is absent from the drug’s label.
A phase 3 study, designated HERIZON-BTC-302, is assessing Ziihera in conjunction with chemotherapy as a first-line treatment for HER2-positive biliary tract cancer. The research is intended to function as the validation trial for Ziihera’s existing rapid approval.
Instead of directly focusing on Herceptin or Perjeta, Jazz is concentrating on Enhertu, a formidable contender in the HER2 domain developed by AZ and Daiichi. In April, the FDA approved Enhertu, making it the first HER2 drug capable of treating specific HER2-positive solid tumors irrespective of their body location.
In a cohort of 22 biliary tract cancer patients participating in the DESTINY-PanTumor02 study, Enhertu had an overall response rate of 45.5%. The limited population size hinders a significant comparison with Ziihera’s statistics.

Notwithstanding Enhertu’s formidable market presence, Cozadd claimed that Ziihera had a persuasive argument in biliary tract cancer. He referenced the number of patients assessed in a study especially tailored for the disease type, together with Ziihera’s tumor response results and tolerability profile. Enhertu, as an antibody-drug conjugate (ADC), has a cytotoxic payload, while Ziihera is a pure antibody without any chemotherapeutic component, Cozadd said.
Jazz has initiated its own pan-tumor investigation, having just commenced the phase 2 DiscovHER-Pan-206 research for Ziihera in HER2-positive solid tumors.

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