After a long period of speculation, Seagen has found a buyer. 

Pfizer is acquiring the cancer-focused biotech in a $43 billion deal, the company announced Monday. The pharma giant, which shot into prominence during the COVID-19 pandemic with its vaccines, is now shifting its attention to oncology.

Pfizer added that the transaction is expected to be completed by the end of 2023 or early 2024.

“Pfizer is deploying its financial resources to advance the battle against cancer, a leading cause of death worldwide with a significant impact on public health,” Pfizer CEO Albert Bourla said in a statement.

The move will double Pfizer’s cancer pipeline as it adds Seagen’s antibody-drug conjugate (ADC) technology to its capabilities. ADCs are a quickly-growing subset of cancer drugs that have the ability to kill cancer cells while preventing off-target toxicities.

Bourla noted that the acquisition will allow both companies to “seek to accelerate the next generation of cancer breakthroughs and bring new solutions to patients” using Seagen’s ADC technology combined with Pfizer’s existing expertise in cancer.

“Oncology continues to be the largest growth driver in global medicine, and this acquisition will enhance Pfizer’s position in this important space and contribute meaningfully to the achievement of Pfizer’s near- and long-term financial goals,” Bourla said.

Pfizer’s oncology pipeline currently consists of 24 drugs approved by the Food and Drug Administration that brought in $12.1 billion of its $100 billion 2022 revenue. The company is also focused primarily on breast cancer, genitourinary cancer, hematology and precision medicine.

The move is partially motivated by Pfizer’s efforts to offset expected revenue loss of $17 billion by 2030, as some of its drugs like blood thinner Eliquis lose patent protection, according toThe Wall Street Journal.

Seagen has said that it expects 2023 revenue to reach about $2.2 billion, marking 12% growth year-over-year. That revenue is based on its current four approved cancer drugs — Adcetris, Padcev, Tivdak and Tukysa. Pfizer noted that it believes Seagen can reach $10 billion in revenue by 2030 with the acquisition.

“The proposed combination with Pfizer is the right next step for Seagen to further its strategy, and this compelling transaction will deliver significant and immediate value to our stockholders and provide new opportunities for our colleagues as part of a larger science-driven, patient-centric, global company,” Seagen CEO David Epstein said in a statement.

The acquisition comes after months of back-and-forth between Seagen and pharma players including Pfizer and Merck – who were eyeing the company for its ADC potential. Last year, Merck was considering an acquisition of Seagen but eventually dropped the deal and instead purhcased Imago BioSciences.