Pfizer acquisition of Seagen: impact evaluation on oncology portfolio

On March 13th, 2023, Pfizer and Seagen announced that they have entered into a definitive merger agreement under which Pfizer will acquire Seagen for a total enterprise value of $43 billion. The two companies hosted an investor call where they discussed the transaction overview, potential long-term growth, as well as Seagen’s ADC platform and how it may fit within Pfizer’s oncology portfolio. The deal is expected to close in late 2023 or early 2024, barring any regulatory setbacks. 

Assessment:

• Acquisition of Seagen complements Pfizer’s established global commercial presence and brand recognition, with a strong ADC-based oncology pipeline; making Pfizer a robust future competitor in oncology
• In the intermediate term, Pfizer’s commercial experience could immediately strengthen the bladder cancer leadership Seagen has developed
• Long term, Pfizer’s global development scale and commercial experience could amplify the success of Seagen’s pipeline in tumor types mUC, Breast, NSCLC
• Implications in Bladder Cancer
  • Pfizer’s commercial infrastructure and bladder cancer leadership could drive stronger uptake of EV in both 2L+ and 1L (+ pembrolizumab, upon expected AA in Apr 2023)
    • Pfizer’s clinical capabilities may also accelerate development of EV in additional mUC populations and in earlier stage bladder cancer, further increasing EV’s first-mover advantage in these settings
    • Through the acquisition, Pfizer gains access to Disitamab vedotin (DV, HER2-targeting ADC), which has potential to enter 1L mUC and other indications
  • While several studies of EV + pembrolizumab are ongoing, Pfizer noted future potential for “portfolio uplift” by combining Seagen ADCs with in-house IO agents such as sasanlimab, which is currently being studied in NMIBC through P3 CREST study
  • EV is also being studied in UC in combination with Evorpacept (ALX148), a CD47 molecule
• Implications in Breast Cancer
  • potential for accelerated development of Seagen’s ADCs in mBC (EV, DV, and LIV-1 targeting ADC, ladiratuzumab vedotin)
  • The combined company will market two approved mBC products, Pfizer’s Ibrance (palbociclib, CDK4/6i) and Seagen’s Tukysa (tucatinib, HER2+ TKI) -  both are products Trodelvy does not directly compete with
• Implications in Lung Cancer
  • Pfizer noted excitement around the development of SGN-B6A (integrin beta-6 ADC) which is currently under investigation in P1 study in solid tumors, including NSCLC.
    • Early results were presented at SITC 2022, and the companies state that future P3 studies in 1L/2L mNSCLC are planned
  • Implications to TIGIT landscape
    • Seagen does have a TIGIT agent (SEA-TGT) in its portfolio
    • SEA-TGT is not in any pivotal studies; however, SEA-TGT is already being studied in P1 combination studies with Pfizer’s PD1 sasanlimab in NSCLC, HNSCC, and melanoma
  • Other pipeline
    • Seagen is planning on advancing a CEACAM5 ADC into the clinic in 2023
    • Pfizer is also a direct competitor in the CD47 space with their acquisition of Trillium and TTI -622 and 621; currently being studied in both heme and solid tumor malignancies
    • Beyond CD47, Pfizer has strong ambitions in hematologic oncology which may be accelerated with the acquisition of Seagen’s Adcetris (brentuximab vedotin)