Tukysa: Breast cancer therapy succeeds in late-stage study

Seagen said on Wednesday that a combination of its therapy, Tukysa, met the main goal of a late-stage study in some breast cancer patients, boosting the prospects of the company that is in the process of being acquired by Pfizer.

Pfizer in March agreed to acquire Seagen and its targeted therapies in a $43 billion deal to help the drugmaker brace for a steep fall in COVID-19 product sales and generic competition for some top-selling drugs.

Tuksya, along with Roche’s Kadcyla, helped extend the time that patients with a type of breast cancer lived without their disease worsening.

Kadcyla belongs to a class of drugs called antibody-drug conjugates (ADC), which have been described as “guided-missile” cancer drugs and the use of these drugs for breast cancer patients has grown in the past few years.

The Roche drug faces competition from Daiichi Sankyo’s and AstraZeneca’s Enhertu.

Tukysa, chemically known as tucatinib, is already approved in combination with Roche’s Herceptin and chemotherapy Xeloda in patients whose cancer has worsened or spread despite at least one prior round of treatment.

In the current trial, the drug was being tested in patients with a type of breast cancer known as HER2 positive, which accounts for 15% to 20% of all breast cancers in the United States.

HER2 protein contributes to the growth and spread of breast cancer.

Breast cancer is the second-most common cancer among women in the United States, according to government data.

About TUKYSA (tucatinib)

TUKYSA is an oral medicine that is a tyrosine kinase inhibitor of the HER2 protein. In vitro (in lab studies), TUKYSA inhibited phosphorylation of HER2 and HER3, resulting in inhibition of downstream MAPK and AKT signaling and cell growth (proliferation), and showed anti-tumor activity in HER2-expressing tumor cells. In vivo (in living organisms), TUKYSA inhibited the growth of HER2-expressing tumors. The combination of TUKYSA and the anti-HER2 antibody trastuzumab showed increased anti-tumor activity in vitro and in vivo compared to either medicine alone.