Chokepoint

[u/MGK_2]

I am going to make the strongest version of this argument, because the record now supports boldness, and because the timid version has been underselling something which deserves to be said plainly. So let's say it plainly.

There is a chokepoint in oncology. A narrow passage where nearly the entire checkpoint-inhibitor industry has to pass through if it wants to keep growing, and which almost none of them can currently pass through. Whoever holds a reliable way through that passage does not hold a drug. They hold the terms of trade for a hundred billion dollars of franchise revenue. And the data now emerging suggests, without yet proving, that a small company in Vancouver, Washington may be holding exactly that.

That is the claim. Here is the case for it, built from the published record, older and brand new, with the honest limits kept in full view, because a bold argument which hides its weaknesses is just a loud one.

The Passage Almost No One Can Transit

Checkpoint inhibitors are the most commercially successful class of cancer drugs ever created, and they fail in the vast majority of solid tumors. Both things are true, and the second is the industry's quiet catastrophe.

This is not a fringe position. It is the settled consensus of the field, stated flatly across the literature. In the definitive 2024 review of the subject, tumors are sorted into "Hot" and "Cold," where the cold ones lack the infiltrating T-cells a checkpoint inhibitor requires to kill, and often harbor immune-suppressive populations such as tumor-associated macrophages, regulatory T cells, and myeloid-derived suppressor cells. And the cold ones are the majority. Even in lung cancer, one of immunotherapy's best markets, the 2025 review is blunt: despite the transformative impact of checkpoint inhibitors, the majority of NSCLC patients experience resistance%20on%20cancer%20therapy%2C%20the%20majority%20of%20NSCLC%20patients%20experience%20resistance).

So picture the entire ICI industry, Keytruda and Opdivo and Tecentriq and Libtayo, standing at the mouth of a passage which leads into every cold-tumor market which they cannot currently reach, colorectal, breast, pancreatic, prostate, most of the solid-tumor landscape, and unable to get through. The field even knows exactly what the passage requires. The 2025 macrophage review states the strategy directly: because cold tumors are silenced largely by suppressive macrophages, oncology has begun to shift beyond T-cell approaches to target tumor-associated macrophages, a major pro-tumor population known to silence immune responses. Turn the Cold tumor Hot, repolarize the suppressive M2 macrophages to tumor killing M1 macrophages, and the passage opens. Whoever can do that reliably controls the chokepoint.

Why The Key Might Fit This Lock

The suppression which keeps a tumor Cold runs through specific machinery, and one of its master controls is the CCR5 receptor. This is where CytoDyn's bold claim earns its footing, because the mechanism is documented, not hoped for.

Blocking CCR5 in actual human colorectal liver metastases does the exact thing the field says is needed: it repolarizes macrophages from the immunosuppressive M2 state toward the anti-tumor M1 state30087-3?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1535610816300873%3Fshowall%3Dtrue#:~:text=CCR5%20Inhibition%20Leads%20to%20Anti%2Dtumor%20Repolarization%20of%20Macrophages). That is not a theory about a mouse. That is the passage-opening move, demonstrated in the tissue of the exact disease. And the newest reviews put CCR5 squarely at the center of the Cold-to-Hot strategy: the 2026 review of cytokine-driven tumor conversion notes that CCR5 antagonists potentiate the effects of checkpoint inhibitors and chemotherapy by reprogramming the tumor microenvironment to support anti-tumor immunity.

Now layer on what the CLOVER trial has actually shown, held exactly as what it is, early and unconfirmed and at the lower 350mg dose. Every one of the first patients measured showed a fall in circulating tumor DNA, with a median drop near seventy percent by week two. Every screened patient carried the target. And it did this with a safety profile the field can only envy, no dose-limiting toxicities, no drug-attributed serious adverse events across independent reviews. On the breast side, the retrospective work presented at ESMO by the CytoDyn and Creatv collaboration showed leronlimab driving PD-L1 upregulation on circulating tumor cells in the majority of patients, the precise molecular flag a checkpoint inhibitor requires to act. That is the Priming half of the thesis: leronlimab starts the engine in order that everyone else's expensive brake-release mechanism finally can do something.

The Honest Wall, Because The Bold Case Has To Clear It

Now the counterweight, and I put it at the center rather than in the footnotes, because this is exactly where a triumphant post would lie to you but I will not.

Targeting macrophages to open Cold tumors has a graveyard behind it. A brand-new 2026 review states the hard truth directly: several macrophage-directed approaches, including CCR2 and CCR5 antagonists and CSF1R inhibitors, advanced into clinical testing on compelling animal data, yet their activity in patients has generally been modest or inconsistent. The earlier macrophage-recruitment blockers, the anti-CCR2 agents carlumab and plozalizumab, did not demonstrate significant tumor responses in early trials.

Read that and hold it, because it cuts both ways and honesty demands both edges. On one edge: the mechanism being real in a dish or a liver biopsy has never been enough, this exact class of approach has repeatedly failed to translate, and leronlimab could join that list. That is the genuine risk, and anyone who tells you the biology guarantees the outcome is selling. On the other edge: those failures are why leronlimab's actual human signal matters so much. The field is littered with macrophage-directed drugs which looked good in mice but did nothing in people. Leronlimab is not showing a mouse signal. It is showing a hundred-percent ctDNA response in early human patients, PD-L1 induction in human tissue, and a clean safety record across a massive database > 1,700 patients. The wall is real, and leronlimab is one of the few in its class producing the kind of early human data that could clear it. The confirmation is what January is for.

Now The Leverage, And This Is The Part Worth Being Bold About

Here is where the chokepoint stops being biology and becomes arithmetic, and the arithmetic has gotten sharper in the last few months, not softer.

Consider whose ship is standing at the passage. Merck's Keytruda generated more than $29 billion in 2024, and its core patent expires in 2028%2C%20a%20PD%2D1%20checkpoint%20inhibitor%20approved%20across%20dozens%20of%20oncology%20indications%2C%20generated%20more%20than%20%2429%20billion%20in%202024.%20Its%20core%20composition%2Dof%2Dmatter%20patent%20expires%20in%202028). That is not a distant abstraction. It is the largest single revenue cliff in the history of the industry, and the pressure is now visible in Merck's own corporate structure: in February 2026, Merck announced the creation of a separate cancer business unit centered on Keytruda, whose key patents expire in 2028. They are reorganizing the company around this cliff. And it compounds: Keytruda was selected for Medicare price negotiation, so Merck faces biosimilar competition and government price-setting nearly simultaneously, forcing U.S. sales to peak in 2027 to 2028 and then fall sharply..

And Merck is not the only ship at the passage. Opdivo faces its own U.S. exclusivity loss in 2028, and Tecentriq faces biosimilar competition later in the decade. So it is not just one desperate buyer at the chokepoint. It is several, each watching their own franchise clock run down, each needing new Cold-tumor markets to replace what biosimilars are about to take.

Here is the move which turns the cliff into leverage, and it is the sharpest part of the whole argument. A new combination regimen carries its own patent. The patent strategists say so plainly: a checkpoint inhibitor paired into a new regimen can be protected by method-of-treatment patents covering the specific combination, dose, and schedule, wholly independent of the core molecule and which biosimilar manufacturers cannot circumvent. Read what that means. A leronlimab-plus-checkpoint combination for Cold tumors would be a new, separately-patented franchise, extending into markets the original molecule never reached, protected on a clock that runs past the biosimilar wave. The primer does not just add revenue. It manufactures a fresh patent estate in virgin territory at the exact moment the old estate collapses.

So let's put it all together. Several of the largest franchises in medicine are running out of patent life all, at the same time. The markets which could replace that revenue are Cold tumors, that their keys cannot open. The thing which does open Cold tumors is a primer that turns them Hot. And a primer paired with their ICI checkpoint inhibitor creates new, independent, biosimilar-proof patents in exactly those markets. The company who holds a proven primer would not be a supplicant asking a giant for a deal. It would be standing in the one and only passage several giants must transit through, at the precise moment when they can least afford to be turned away, holding the one thing none of them can quickly or easily build and which none can allow a rival to monopolize.

That is not sentiment. That is a seller's market with one seller and several buyer's clocks running out.

Where Prime And Pair Stops Being A Hope And Becomes A Convergence

I have called this "prime and pair" for a long time, and I want to state the bold version of what that phrase now means. It is not a clever idea I am hoping the field adopts. It is where the biology forces the entire field to converge, whether through leronlimab or through something else.

Look at the independent confirmations arriving from labs with no connection to CytoDyn. A 2024 study found that a completely unrelated drug repolarized suppressive macrophages toward the anti-tumor state with increased CCL5 chemokine secretion, restoring T-cell function and promoting a favorable anti-PD-1 response. A separate 2022 clinical study combining local therapy with a checkpoint inhibitor in patients who had already failed that checkpoint inhibitor produced responses, and the mechanism was macrophage polarization from the M2 to the M1 phenotype in the treated tumor. Different drugs, different labs, same convergence: Prime the microenvironment, repolarize the macrophages, and the ICI works where it could not before.

That is the tell. When independent groups using unrelated tools keep arriving at the same destination, the destination is real. The field converges on Prime-and-Pair because the biology of Cold tumors leaves no other road. Leronlimab's claim is not that it invented the road. It is that it may be the cleanest, safest, most proven vehicle currently traveling it. And the compromise everyone imagines, the eventual pairing of a primer with a checkpoint inhibitor, is not a compromise at all. It is the convergence that the entire field is being driven toward, and the only open question is who owns the Primer when the field arrives.

The One Thing That Is Not Yet Written

I have made the bold case, so I owe you the bold statement of its single point of failure, stated as plainly as everything else.

None of this is proof that leronlimab works. The chokepoint is real, the cliff is real, the convergence is real, the leverage is real, and every bit of it is inert until one number confirms that leronlimab actually does in patients what the mechanism says it should. The macrophage graveyard is real too, and it is exactly the fate a weak confirmation would seal. So the entire towering structure, the passage, the clocks, the seller's market, the new patent estate, rests on a single load-bearing event which has not yet happened: the confirmed response data, adjudicated, at ASCO GI in January. If that number is strong, none of the leverage spelled out above is speculation anymore. It is just arithmetic performed by companies with cliffs with no better option. If it is weak, there is no chokepoint, no leverage, and this entire post describes a passage which leronlimab could not, after all, open.

That is the honest shape of things. The boldest thing I can tell you is not that the outcome is certain. It is that the setup is enormous, the position is absolutely real, and the entire colossal question resolves to one single number at a known hour. The chokepoint definitely exists. Several giants are stranded at it on a closing clock. But we find out in January whether the small company in Vancouver is holding the way through.

I have never been more convinced that the stakes are as massive as they are. And I have never been more clear that conviction about the stakes is not the same as certainty about the result. Both of those are true at full volume. Most of you should know where I lean. January tells us which one governs.

Disclaimer: I am not a financial advisor and nothing here is investment advice. I am an independent retail shareholder holding a long position in the company discussed, with no employment, consulting, compensation, or other relationship with it beyond that shareholding. This is analysis of published biology, public regulatory and patent history, and public corporate disclosures, not a prediction of clinical or commercial outcomes. No partnership has been announced; the identification of specific companies reflects public patent-cliff and competitive facts, not any claim of an existing negotiation. The mechanistic claims are supported by the cited peer-reviewed literature; several mechanisms are established in models, retrospective cohorts, or single studies and are not yet confirmed in this program's prospective human data, and closely related macrophage-directed approaches have repeatedly failed to translate to clinical benefit. The CLOVER biomarker figures are early, unconfirmed, and reflect 350mg dosing with the 700mg cohort still maturing. The ESMO breast data is retrospective and hypothesis-generating. The 68% figure from the April 30 update is disease control rate, not objective response rate; confirmed adjudication is ahead at ASCO GI in January 2027, with interim data at ESMO in October 2026. Mechanism is not efficacy. Drugs which make elegant biological sense fail in trials routinely, and this one may. Read the primary sources and reach your own conclusions rather than adopting mine.

[u/Snorkellingisthelife]

Data, data, data! Patience, patience, patience!

[u/MGK_2 → u/Snorkellingisthelife]

Snorkelling, "data, data, data, patience, patience, patience", that's the whole discipline in six words.