Pfizer Licenses Shelved Seagen CD228 ADC to Medicus

Pfizer (NYSE: PFE) is handing its shelved Seagen antibody-drug conjugate PF-08046031, also called CD228V, to Medicus Pharma (Nasdaq: MDCX) in a co-development deal that could top $1 billion. Medicus pays $12 million upfront and another $15 million on the deal’s first anniversary, while Pfizer chips in $2 million of development funding. Pfizer keeps patent ownership, budget oversight, and a cut of any future sublicensing proceeds; Medicus takes on the manufacturing, regulatory, and commercialization work.

The headline number matters less than the near-term cash, as this guide to licensing-deal economics explains. Only $12 million of the “up to $1 billion” is guaranteed at closing; the rest is development, regulatory, and sales milestones Pfizer collects only if the drug reaches market, plus low-double-digit tiered royalties. For Medicus, a microcap with about 63 million shares outstanding that closed down 34% at $0.17 on roughly 97 million shares traded, the real cost is the $27 million it owes Pfizer over the next year. That exceeds the company’s market value, which sat near $11 million after Thursday’s slide.

CD228V is a vedotin-class antibody drug conjugate: a humanized antibody (hL49) that binds CD228, also called melanotransferrin, with an average of four molecules of the cell-killing payload MMAE attached. CD228 is highly expressed on melanoma cells and several other solid tumors, and no approved drug yet targets it. The vedotin linker-and-payload design is the same one behind Seagen’s approved Adcetris and Padcev, so the pharmacology is well understood even if this particular target is unproven. The asset arrived with Pfizer’s $43 billion Seagen acquisition, and Pfizer scrapped the Phase 1 trial, launched in May 2025 in advanced melanoma with expansion into lung, head-and-neck, and esophageal cancers, earlier this year.

The target is real but unproven. Pfizer is not abandoning CD228 entirely. It still runs PF-08046049, a CD228 x 4-1BB bispecific in Phase 1 for melanoma. But the move is clearly part of a Seagen portfolio prune, after a separate Seagen-inherited ADC failed a Phase 3 lung cancer readout. Medicus CEO Raza Bokhari called the deal “a defining milestone” that moves the company into precision oncology.

The risk is plain: Medicus must now fund a clinical-stage ADC on a balance sheet worth less than its first-year obligation, and Thursday’s 34% drop suggests the market is already pricing in dilution. Watch whether Medicus raises capital to cover the $27 million, and whether it restarts the Phase 1 that Pfizer walked away from.

Source: Fierce Biotech