Medicus Pharma Licenses Pfizer's Discontinued CD228-Targeted ADC in Deal Worth Over $1 Billion

Medicus Pharma, through its wholly owned subsidiary Medicus Oncology, entered into a co-development and license agreement with Pfizer covering PF-08046031, also designated CD228V, an early clinical-stage antibody-drug conjugate (ADC) directed against melanotransferrin (CD228, also known as MELTF or MFI2).¹ The agreement grants Medicus an exclusive, sublicensable, worldwide license to develop, manufacture, and commercialize the asset, while Pfizer retains ownership of the underlying patent estate and a continuing oversight role; Medicus must share development plans and budgets with Pfizer for review, and Pfizer holds an option to fund all or part of future development once a pivotal trial begins.¹

Medicus paid Pfizer a $12 million upfront payment, with an additional $15 million due on the agreement's first anniversary, while Pfizer contributed $2 million in development funding to support early-stage advancement of the program.¹ Pfizer is eligible for development, regulatory, and sales milestone payments that could exceed $1 billion in aggregate, plus tiered, low double-digit royalties on net sales.¹

Raza Bokhari, MD, executive chairman and chief executive officer of Medicus Pharma, said the partnership "represents a defining milestone for Medicus and significantly expands our presence in precision oncology," adding, "We further believe that this co-development agreement with Pfizer substantially enhances our long-term growth profile and positions the Company to participate in one of the most dynamic sectors of biotechnology."²

Where did this asset come from?

PF-08046031 originated from Pfizer's 2023 acquisition of Seagen for approximately $43 billion, a deal that brought Seagen's ADC platform and pipeline into Pfizer's oncology portfolio.³ Pfizer began a phase I trial of the asset, then known as SGN-CD228A, in May 2025 as a monotherapy study in advanced melanoma, with additional cohorts evaluating lung, head and neck, and esophageal tumors.¹ Pfizer discontinued that trial earlier in 2026 as part of a broader reassessment of programs acquired through the Seagen transaction — a reassessment that has also included other early-stage program discontinuations and a separate phase 3 trial failure in non-small cell lung cancer for a different Seagen-derived ADC.¹

How does CD228V work, and why target melanotransferrin?

PF-08046031 is composed of hL49, a humanized IgG1 monoclonal antibody specific to CD228, conjugated to monomethyl auristatin E (MMAE) via a protease-cleavable valine-citrulline linker of the vedotin class, at an average drug-to-antibody ratio of four.¹ Melanotransferrin was first characterized as a cell-surface protein in melanoma and has since been identified across additional solid tumor types; immunohistochemical and RNA-sequencing analyses cited in support of the program indicate CD228 expression is limited in normal tissue but elevated across several malignancies associated with sensitivity to microtubule-disrupting payloads, including melanoma, squamous non-small cell lung cancer, triple-negative breast cancer, colorectal cancer, and pancreatic cancer.¹ No CD228-directed therapy has received regulatory approval to date.¹

The scientific rationale draws on peer-reviewed preclinical work describing SGN-CD228A, a related construct built on the same hL49 antibody backbone, which found the anti-CD228 antibody was efficiently internalized across multiple tumor cell types, with cytotoxic activity dependent on CD228 expression, internalization, and intrinsic MMAE sensitivity.⁴ That publication evaluated a different linker chemistry than the one used in PF-08046031, so the two should be understood as related but distinct constructs sharing a common antibody and payload class, rather than interchangeable descriptions of the same molecule.¹

Payload and linker design remain a central axis of competition across the ADC field more broadly. Dave Simpson, chief executive officer of Iksuda Therapeutics, told BioPharm International in a video interview that "the biggest innovation moving forward is on the payload side," pointing to payload design and antibody engineering, alongside linker and conjugation advances, as the areas most likely to shape the next generation of ADCs.⁵

What happens next?

Medicus said its near-term priorities include advancing CD228V through further clinical development under its own sponsorship, incorporating the manufacturing, regulatory, and budgetary planning processes specified in the agreement.¹ The company has characterized the transaction as a foundational addition to its oncology pipeline and a step toward building a broader portfolio of differentiated ADC programs.¹ As with any early-stage oncology asset transitioning between sponsors, the program's path forward will depend on the design and outcome of subsequent clinical studies; CD228V remains investigational, with safety and efficacy not yet established.¹

References

1. Medicus Pharma Secures Worldwide Rights to Pfizer's Discontinued CD228-Directed ADC in Deal Valued at Over $1 Billion. ADC Review. Published September 3, 2026. Accessed September 4, 2026.
2. Pfizer offloads scrapped Seagen ADC to Medicus Pharma in up to $1B+ deal. Fierce Biotech. Published September 3, 2026. Accessed September 4, 2026.
3. Pfizer to Acquire Seagen in $43 Billion Blockbuster Deal. BioPharm International. Published March 16, 2023. Accessed September 4, 2026.
4. Mazahreh R, Mason ML, Gosink JJ, et al. SGN-CD228A Is an Investigational CD228-Directed Antibody-Drug Conjugate with Potent Antitumor Activity across a Wide Spectrum of Preclinical Solid Tumor Models. Mol Cancer Ther. 2023;22(4):421-434. doi:10.1158/1535-7163.MCT-22-0401.
5. Iksuda Wins FDA IND Clearance for CA242-Directed ADC IKS04 in GI Cancers. BioPharm International. Published July 30, 2026. Accessed September 4, 2026.