US-based pharmaceutical firm Gilead Sciences has agreed to acquire Immunomedics, a developer of antibody-drug conjugates (ADC) platform, for $21bn.

Under the terms of the transaction, Gilead will place a tender offer to purchase all the outstanding shares of Immunomedics at a price of $88 per share, which indicates around 108% premium over the closing price on 11 September 2020.

The pharmaceutical firm said that the tender offer is not subject to a financing condition and is planning to fund the transaction through around $15bn available cash, along with $6bn in new debt.

The transaction will benefit Gilead with Trodelvy (sacituzumab govitecan-hziy), an advanced Trop-2 directed antibody-drug conjugate, developed by Immunomedics.

Gilead Sciences chairman and chief executive officer Daniel O’Day said: “This acquisition represents significant progress in Gilead’s work to build a strong and diverse oncology portfolio. Trodelvy is an approved, transformational medicine for a form of cancer that is particularly challenging to treat.

“We will now continue to explore its potential to treat many other types of cancer, both as a monotherapy and in combination with other treatments. We look forward to welcoming the talented Immunomedics team to Gilead so we can continue to advance this important new medicine for the benefit of patients with cancer worldwide.”

Trop-2 directed ADC Trodelvy is being studied in various clinical trials

Gilead stated that the drug is being studied in various clinical trials, including the Phase 3 ASCENT study, a Phase 3 trial in third-line HR+/HER2- breast cancer and a registrational Phase 2 study in bladder cancer.

In the Phase 3 ASCENT study, which was halted early, Trodelvy significantly improved progression-free survival (PFS) and overall survival (OS) in previously treated patients with advanced mTNBC. Other clinical trials evaluating Trodelvy to treat non-small cell lung cancer and other solid tumour types.

In April this year, the drug has received accelerated US Food and Drug Administration (FDA) approval to treat adult patients with metastatic triple-negative breast cancer (mTNBC) who have received at least two prior therapies for metastatic disease.

The cancer drugmaker intends to file a supplemental Biologics License Application (BLA) seeking US FDA approval of Trodelvy in the fourth quarter of 2020. The company is also planning to seek European regulatory approval in the first half of 2021.

Immunomedics executive chairman Behzad Aghazadeh said: “We are very pleased that Gilead recognized the value of Trodelvy, both for the important role it has already begun to play for patients with metastatic triple-negative breast cancer and for its potential to help many other patients with cancer in the future.

“We are excited for the opportunities ahead of us as we join with Gilead to advance our shared mission in defeating cancer. By working with Gilead, we have the opportunity to accelerate our progress and improve care for patients in need of new therapies.”