Protein Degraders: 2 FDA Approvals, 5 Pure-Plays Ranked

The biggest oncology story of 2026 is not an ADC and it is not a bispecific. It is a drug class most investors still cannot define, and it just went two for two at the FDA inside three months.

Bristol Myers Squibb’s Zenbexus (iberdomide) won accelerated approval on August 13, 2026 as the first CELMoD, on EXCALIBER-RRMM data showing a 41% minimal residual disease-negative complete response rate versus 21% for the daratumumab, bortezomib, dexamethasone control arm (p<0.0001). Arvinas and Pfizer’s VEPPANU (vepdegestrant) beat its June 5 PDUFA date to become the first approved PROTAC. Two different engines, one shared idea: instead of blocking a disease-causing protein, you order the cell’s own garbage disposal to destroy it.

The two drugs that proved the class works were both monetized by somebody other than the pure-play biotech that mattered. Bristol Myers sells Zenbexus itself. Arvinas, the company that invented the PROTAC, handed VEPPANU to Rigel Pharmaceuticals for $70 million upfront plus $15 million in milestones, split evenly with Pfizer. A $600 million market cap company gave away its approved crown jewel for roughly $35 million net to itself. That disconnect is the trade. The modality is de-risked, and the pure-plays are still priced like it is not.

The field runs on two engines. PROTACs are heterobifunctional: one end grabs the disease target, the other grabs an E3 ligase, and the linker drags the two together so the ligase tags the target for destruction by the proteasome. Molecular glues are monovalent: they reshape an E3 ligase’s surface so it grabs an undruggable target on its own. CELMoDs, the cereblon modulators behind Revlimid and now Zenbexus, are the proven glue subclass.

Zenbexus validated the glue side. VEPPANU validated the PROTAC side. Neither validated the pure-play economics, and that is exactly where the opportunity sits. Here is the field, ranked by nearest catalyst, with prices from Polygon’s August 28 close.

Kymera (KYMR): $118.15, $9.8 billion. The leader, and it is already priced.

Kymera is no longer the IRAK4 story. Its lead is KT-621, a first-in-class oral degrader of STAT6, the transcription factor that drives IL-4 and IL-13 signaling and the central engine of Type 2 inflammation. In Phase 1, KT-621 showed median STAT6 degradation of at least 98% in blood and skin, with clinical activity in atopic dermatitis and comorbid asthma. That is the “Dupixent in a pill” thesis. Dupixent, the injectable antibody KT-621 would displace, is a $20 billion-plus-a-year franchise, so a once-daily oral that matches it is worth far more than $9.8 billion if it works. The market has already bought that possibility.

The catalyst: enrollment in the BROADEN2 Phase 2b atopic dermatitis trial completed on June 25, 2026, with topline data accelerated to year-end 2026. A second Phase 2b in eosinophilic asthma runs in parallel, and KT-621 holds Fast Track designation in asthma.

The take: $9.8 billion prices a best-case outcome before the registrational data exists. Kymera is a Hold, not a chase. If you own it, fine. If you do not, the year-end readout is the binary to trade, and you are late to the front-running.

Nurix (NRIX): $26.21, $2.7 billion. The best risk-reward in the group.

Bexobrutideg (NX-5948) is an oral, brain-penetrant degrader of Bruton’s tyrosine kinase, and it does what covalent BTK inhibitors cannot: it destroys the BTK protein itself, including the mutated forms that drive resistance. In the randomized Phase 1b CLL data, the 600 mg recommended dose showed an 83.3% overall response rate versus 73.7% at 200 mg (descriptive Phase 1b, not powered for dose comparison), in patients with a median of three prior lines of therapy, 85.7% of whom had already failed a BTK inhibitor. Responses held up across C481S and non-C481S resistance mutations and in patients with CNS involvement. The Phase 1a/1b study is the source, and the DAYBreak registrational Phase 2 in relapsed or refractory CLL is enrolling now.

Roche is co-developing bexobrutideg, which de-risks the financing. A $2.7 billion market cap for a Roche-partnered BTK degrader with an 83% response rate in the most resistant CLL population is the cheapest entry point in this entire field. Buy the dips. This is the name to own.

Monte Rosa (GLUE): $13.38, $1.1 billion. Small, but the glue trade is real.

MRT-2359 is a GSPT1-directed molecular glue degrader, the only true glue pure-play beyond the CELMoDs. In heavily pretreated metastatic castration-resistant prostate cancer, the combination with enzalutamide produced a 100% PSA response rate in the five patients with androgen receptor mutations, with two confirmed partial responses and 100% disease control. Across all 15 evaluable patients, disease control was 67% with tumor shrinkage in 10 of 15. The Phase 1/2 study is the source.

The sample is tiny, and that is the point. MODeFIRe-1, a two-stage Phase 2 with apalutamide in AR-mutant patients, starts in Q3 2026 with up to 25 patients. This is a speculative buy: 1% of a portfolio, no more. The upside is a re-rate from $1.1 billion toward the $2 billion plus that a validated GSPT1 glue in a defined prostate cancer niche would command.

C4 Therapeutics (CCCC): $3.85, $474 million. The smallest, and the least de-risked.

Cemsidomide (CFT7455) is an IKZF1/3 MonoDAC degrader in Phase 1/2 for multiple myeloma, using a 14 days on, 14 days off schedule to manage neutropenia. Early data showed deep IKZF1/3 degradation and anti-myeloma activity, but this is still dose escalation. C4 is the most capital-constrained name here, with no near-term binary catalyst. Avoid until there is a dose-expansion readout with a response rate worth trading on.

Arvinas (ARVN): $9.18, $600 million. The cautionary tale, not the trade.

Arvinas invented the PROTAC and got VEPPANU approved, then licensed the global rights to Rigel for $70 million upfront plus $15 million in milestones. That deal, split with Pfizer, netted Arvinas roughly $35 million up front for a drug the NCCN has already slotted into breast cancer guidelines as a Category 2A option. If you want to understand why the market prices Arvinas at $600 million despite owning a piece of the first approved PROTAC, that deal is the answer. The pure-play economics of degraders only work if you keep the commercial upside, which is the same lesson every big pharma patent cliff M&A target teaches. Arvinas did not keep it. Avoid until the balance sheet and the next asset say otherwise.

The pattern across all five names is the same: the science is progressing faster than the business models. Kymera has the best science and the fullest price. Nurix has the best science per dollar. Monte Rosa has the best pure-glue story and the smallest sample. C4 has the most to prove and the least cash. Arvinas is the proof that a working drug is not the same thing as a working stock.

Risks

The two approvals both carried asterisks. Zenbexus is an accelerated approval whose full benefit rests on progression-free survival, the trial’s other primary endpoint, which is still maturing. VEPPANU’s win was a 2.9-month median PFS improvement over fulvestrant in a narrow ESR1-mutant subset, which is why Arvinas and Pfizer sold it cheap instead of building a sales force. And Kymera’s $9.8 billion already prices a “Dupixent pill” outcome that a single failed Phase 2b could reset. The crowded oncology catalyst calendar means these names are fighting for the same incremental dollar.

Verdict

Ranked by risk-reward, not by market cap: Nurix first, Monte Rosa second, Kymera a Hold, C4 an Avoid, and Arvinas the lesson. These are binary names. Size them at 1 to 2 percent of a biotech portfolio each, and treat the year-end KT-621 readout as the sector’s bellwether. If KT-621 hits, the whole field re-rates. If it misses, the pure-plays give back the Zenbexus and VEPPANU premium in a single session. You can find the full ranked biotech catalyst list here.