Just ahead of World ADC, the industry meeting for anyone involved in the development, manufacturing antibody-drug conjugates, and the annual meeting of the European Society for Medical Oncology (ESMO), Gilead Sciences and Immunomedics confirmed that the companies have entered into a definitive agreement allowing which Gilead to acquire Immunomedics for US $ 88.00 per share in cash.

The price represents a 108% premium to Immunomedics’ closing price on September 11, 2020. Following successful completion of the tender offer, Gilead will acquire all remaining shares not tendered in the offer through a second-step merger at the same price as the tender offer.

The transaction, which values Immunomedics at approximately US $ 21 billion, was unanimously approved by both the Gilead and Immunomedics Boards of Directors and is anticipated to close during the fourth quarter of 2020.

Antibody-drug Conjugates
The agreement gives Gilead access to Immunomedics next-generation antibody-drug conjugate (ADC) technology, which centers on using a novel linker that does not require an enzyme to release the payload to deliver an active drug inside the tumor cell and the tumor microenvironment, thereby producing a bystander effect.

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In addition, Gilead obtains sacituzumab govitecan-hziy (Trodelvy™), a first-in-class Trop-2 directed antibody-drug conjugate (ADC) that was granted accelerated approval by the U.S. Food and Drug Administration (FDA) in April 2020 for the treatment of adult patients with metastatic triple-negative breast cancer (mTNBC) who have received at least two prior therapies for metastatic disease.[1][2][3]

Biologics License Application
Immunomedics plans to submit a supplemental Biologics License Application (BLA) to support the full approval of sacituzumab govitecan in the United States in the fourth quarter of 2020. Immunomedics is also on track to file for regulatory approval in Europe in the first half of 2021.

In the Phase III ASCENT study, which was halted early due to efficacy based on the unanimous recommendation of the independent Data Safety Monitoring Committee, sacituzumab govitecan significantly improved progression-free survival (PFS) and overall survival (OS) in previously treated patients with advanced mTNBC. Detailed results from this study are expected to be presented at the upcoming European Society for Medical Oncology (ESMO) Virtual Congress 2020.

Beyond mTNBC, presentations during the ESMO meeting include highlights from the TROPHY U-01 study in metastatic urothelial cancer, as well as an investigator-sponsored study of Trodelvy in brain tumors. Sacituzumab govitecan is also being studied in an ongoing Phase III trial in third-line HR+/HER2- breast cancer and a registrational Phase II study in bladder cancer.

Additional ongoing studies are evaluating the potential of sacituzumab govitecan as a treatment for non-small cell lung cancer and other solid tumor types. Sacituzumab govitecan is being studied as both a monotherapy and in combination with checkpoint inhibitors and other non-immuno-oncology products by Immunomedics and independent investigators. Additional clinical data for sacituzumab govitecan in bladder cancer and other solid tumors will also be presented at ESMO this coming week.

Significant progress
“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,” said Daniel O’Day, Chairman, and Chief Executive Officer, Gilead Sciences.

“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,” O’Day continued.

“We are very pleased that Gilead recognized the value of sacituzumab govitecan – 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,” said Behzad Aghazadeh, Ph.D., Executive Chairman of Immunomedics.

“We are excited about 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,” Aghazadeh concluded.

Strategic Benefits

  • Rapidly Expanding Trodelvy’s Benefit for Patients Globally: After closing Gilead intends to initiate numerous additional mid- and late-stage studies in the near term to determine which patients will benefit from sacituzumab govitecan as both a monotherapy or in combination with other products.
  • Gilead brings commercial, medical, regulatory, and manufacturing expertise, which will help rapidly advance sacituzumab govitecan through the development and reach additional patients. Gilead will also bring to Immunomedics an established infrastructure and operations in Europe and Japan to support the launch of sacituzumab govitecan in those regions, pending approval. After closing, Gilead will retain global rights to sacituzumab govitecan outside of greater China, South Korea, and certain Southeast Asian countries.
  • Sacituzumab govitecan is expected to a foundational drug for Gilead’s Oncology Franchise: Sacituzumab govitecan will bring to Gilead a cornerstone product that broadens and deepens the company’s solid tumor pipeline, building on currently marketed products and late-stage clinical candidates for patients with hematological malignancies at Kite and Gilead, including axicabtagene ciloleucel (Yescarta®), brexucabtagene autoleucel (Tecartus) and magrolimab, a first-in-class investigational monoclonal antibody against CD47 and macrophage checkpoint inhibitor that is designed to interfere with recognition of CD47 by the SIRPα receptor on macrophages, thus blocking the “don’t eat me” signal used by cancer cells to avoid being ingested by macrophages.
  • Sacituzumab govitecan is approved as a third-line treatment for mTNBC and has shown promise for earlier stages of the disease. TNBC represents approximately 15 to 20 percent of all breast cancer cases and is generally considered the most aggressive form of breast cancer. HR+/HER2- breast cancer accounts for more than 70% of all breast cancers.
  • Accelerates Gilead’s Revenue and EPS Growth: sacituzumab govitecan was launched in May of 2020 and has significant commercial potential in mTNBC and other solid tumors. In addition to immediately accelerating Gilead’s revenue growth, the acquisition of Immunomedics is expected to be neutral to accretive to Gilead’s non-GAAP EPS in 2023 and significantly accretive thereafter.

Tender
The consummation of the tender offer is subject to various conditions, including a minimum tender of at least a majority of outstanding Immunomedics shares, the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act, and other customary conditions.

The tender offer is not subject to a financing condition and will be funded through approximately US $ 15 billion in cash on hand, as well as approximately US $ 6 billion in newly issued debt. Gilead expects to retain an investment-grade credit rating following this transaction and this agreement does not alter Gilead’s stated capital allocation strategy or its commitment to maintain and grow its dividend over time.

Drug Description
Sacituzumab govitecan (IMMU-132] [Drug Map][Description]

Clinical trials
ASCENT-Study of Sacituzumab Govitecan in Refractory/Relapsed Triple-Negative Breast Cancer (ASCENT) – NCT02574455
Sacituzumab Govitecan In TNBC (NeoSTAR) – NCT04230109
Study of IMMU-132 in HR+/HER2- MBC (TROPICS-02) – NCT03901339
Study of Sacituzumab Govitecan (IMMU-132) in Metastatic or Locally Advanced Unresectable Urothelial Cancer (TROPiCS-04) – NCT04527991
Rollover Study in Subjects With Metastatic Solid Tumors Benefiting From Therapy With Sacituzumab Govitecan – NCT04319198

Highlights of prescribing information
Sacituzumab govitecan-hziy (Trodelvy™; Immunomedics)[Prescribing information]
Axicabtagene ciloleucel (Yescarta®; Kite/Gilead)®)[Prescribing Information]
Brexucabtagene autoleucel (Tecartus™; Kite/Gilead)[Prescribing Information]

Presentations during the virtual ESMO 2020
Thursday, September 17, 2020 (9:00 Central European Summer Time (CEST) (3:00 a.m. Eastern Time).

  • Phase 1b/2 study of antibody-drug conjugate, sacituzumab govitecan, in combination with the PARP inhibitor, talazoparib, in metastatic triple-negative breast cancer (Bardia, et al.) Session Title: Poster Display – Breast Cancer, Metastatic
    Poster #: 358TiP
  • TROPHY-U-01 cohort 3: sacituzumab govitecan (SG) and pembrolizumab (pembro) in patients (pts) with progression or recurrence of metastatic urothelial cancer (mUC) after platinum (PLT)-based therapy (Grivas, et al.). Session Title: Poster Display – Genitourinary Tumours, Non-Prostate. Poster #: 796TiP

Friday, September 18, 2020 (12:01-12:06 CEST (6:01-6:06 a.m. Eastern Time)

  • Delivery and activity of SN-38 by sacituzumab govitecan in CNS Tumors (Brenner, et al.)
    Session Title: Mini Oral – CNS – Presentation #: 373MO

Saturday, September 19, 2020

  • ASCENT: A randomized phase 3 study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with previously treated metastatic triple-negative breast cancer (mTNBC) (Bardia, et al.). Session Title: Proffered Paper 1 – Breast cancer, metastatic Session Time: 16:20-18:00 CEST/ Presentation #: LBA17
    Presentation Time: 17:04-17:16 CEST (11:04-11:16 a.m. Eastern Time) (Channel 1)
  • TROPHY-U-01 cohort 1 final results: A Phase 2 study of sacituzumab govitecan (SG) in metastatic urothelial cancer (mUC) that has progressed after platinum (PLT) and checkpoint inhibitors (CPI) (Loriot, et al.). Session Title: Proffered Paper 1 – GU, non-prostate. Session Time: 16:20-18:00 CEST/Presentation #: LBA24 Presentation Time: 17:04-17:16 CEST (11:04-11:16 a.m. Eastern Time) (Channel 3)

References
[1] FDA Grants Accelerated Approval for Sacituzumab Govitecan in Metastatic Triple-negative Breast Cancer. ADC Review | Journal of Antibody-drug Conjugates. April 22, 2020 [Article]
[2] Syed YY. Sacituzumab Govitecan: First Approval. Drugs. 2020;80(10):1019-1025. doi:10.1007/s40265-020-01337-5
[3] Rugo HS, Bardia A, Tolaney SM, et al. TROPiCS-02: A Phase III study investigating sacituzumab govitecan in the treatment of HR+/HER2- metastatic breast cancer. Future Oncol. 2020;16(12):705-715. doi:10.2217/fon-2020-0163