Gilead’s Breast Cancer Drug that Came off a $21 Billion Buyout Finally Gets FDA’s Full Approval

After hitting multiple roadblocks, Gilead Sciences announced on April 7th that Trodelvy, its antibody drug conjugate (ADC) for metastatic triple negative breast cancer (mTNBC), had finally secured full approval from the FDA based on data from clinical trial ASCENT.

“Today’s approval is the culmination of a multi-year development program and validates the clinical benefit of this important treatment in metastatic TNBC,” said Merdad Parsey, MD, Ph.D., Chief Medical Officer, Gilead Sciences.

He further added, “Building upon this milestone, we are committed to advancing Trodelvy with worldwide regulatory authorities so that, pending their decision, Trodelvy may become available to many more people around the world who are facing this difficult-to-treat cancer.”

TNBC accounts for approximately 15% of all breast cancer cases and is predominantly found in younger/premenopausal African American and Hispanic women. TNBC cells test negative for estrogen receptors, progesterone receptors, and excess HER2 protein, which means that the cancer is not driven by the hormones or by the HER2 protein. Hence, treatment options to date remain few.

Trodelvy, a major asset that came off a staggering $21 billion acquisition of Immunomedics by Gilead, had previously managed only to get conditional approvals, which led top officials to pack their bags and make a quick run for the exit.

ASCENT Clinical Trial

ASCENT is an open-label, randomized, and Phase 3 trial which enrolled a total of 529 patients with TNBC who had received multiple (more than two) prior systemic therapies and at least one of them for metastatic disease.

ASCENT was reportedly halted much earlier than the deadline as Immunomedics claimed they had substantial data to prove that Trodelvy was highly efficient in treating TNBC.

Trodelvy which uses an antibody to target Trop-2, a receptor present on cell surface overexpressed by multiple tumors, delivers SN-38, a lethal metabolite of irinotecan, to the tumors.

Patients were randomized and received either Trodelvy or chemotherapy chosen by the physician. Results from the study show that Trodelvy managed to reduce the risk of death by 49% over chemotherapy while improving on progression free survival in patients. (11.8 months for Trodelvy vs. 6.9 months for chemo).

Gilead’s Road Ahead

Previously Immunomedics tried roping in Seattle Genetics for an unsuccessful deal worth $2 billion, after which the company decided to wait for the right buyer, and Gilead showed up.

Now, with an FDA approval in hand, Gilead needs to amplify its sales in order to justify the acquisition of Immunomedics.

Market analysts have predicted that Trodelvy should be bringing in peak sales of approximately $5 billion in the breast cancer market, which should make Gilead heave a sigh of relief.

Gilead is keeping its fingers crossed and hoping that two major events go their way. The first one being data from the Phase 3 trial TROPiCS-02 for third-line HR-positive, HER2-negative breast cancer, which is expected to come out by the end of 2021. The other would be bagging FDA approval for Trodelvy in metastatic bladder cancer. This would pave the way for Gilead to compete in the big league dominated by immune checkpoint inhibitors, namely Roche’s Tecentriq and Merck’s Keytruda.

Related Article: Trodelvy Gives New Hope to Patients with Relapsing Breast Cancer

Author

Tulip Chakraborty