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Hematology I · Case-HemNeoplastic-0003 — Hematologic Neoplastic Disorders

Polycythemia Vera: When the Standard First Drug Is the One His Legs Can't Take

The guideline's first-choice cytoreductive agent for high-risk polycythemia vera has a characteristic toxicity, and it lands on exactly the tissue this patient spent five years getting to heal.

Abbreviations, terms, and other agents mentioned in this case PV — polycythemia vera  ·  JAK2 — Janus kinase 2 — the mutated kinase driving most PV  ·  RESPONSE — the phase 3 trial establishing ruxolitinib for hydroxyurea-resistant/intolerant PV  ·  PROUD-PV/CONTINUATION-PV — the trial pair comparing pegylated interferon alfa-2a against hydroxyurea in PV  ·  JAK1/2 — Janus kinase 1 and 2 — the signaling enzymes ruxolitinib inhibits
Presentation

T.M., a 67-year-old retired postal carrier, spent five years managing chronic venous stasis ulcers on both lower legs — slow-healing wounds that finally closed with compression eighteen months ago and have stayed closed since, though the skin over both malleoli is still thin and atrophic where they were, which is the part of his exam that ends up mattering. Routine labs ordered for unrelated fatigue this spring found a hemoglobin of 19.2 g/dL and a hematocrit of 58%, thirteen points above the under-45% ceiling phlebotomy is supposed to hold him beneath, with a platelet count of 410,000 alongside it. A JAK2 V617F mutation confirmed polycythemia vera. He has never had a thrombotic event, so it is his age by itself — over 60, one of only two variables the conventional risk split uses — that places him in the high-risk group and makes cytoreduction, rather than phlebotomy and aspirin indefinitely, the expected next step.

Hydroxyurea would ordinarily be the answer here, and for most high-risk PV patients that recommendation isn't seriously contested. Its problem in his case is anatomical rather than systemic. The drug produces cutaneous ulcers that are characteristically malleolar, often painful, and notoriously indolent — and malleolar is precisely where his skin is thinnest, most scarred, and five years' worth of hard-won closed. Nothing about his polycythemia makes him likelier than anyone else to develop that toxicity; what his history changes is the price of it if he does, which is a different kind of argument from a risk-factor argument and appears nowhere in any thrombosis score. So the room is not weighing a common toxicity against a rare one. It is weighing a drug reaction that most patients recover from against a wound in this particular man that took half a decade to close the first time, with the tissue that closed it now measurably thinner than it was.

T.M. · 67 New diagnosis
History
Chronic venous stasis ulcers, bilateral lower extremities, healed 18 months ago on compression therapy
Presenting labs
Hgb 19.2 g/dL, Hct 58%, platelets 410,000
Molecular
JAK2 V617F positive
Risk stratification
High risk (age >60)
Thrombosis history
None
Current management
Therapeutic phlebotomy, low-dose aspirin
Skin exam
Both lower legs fully healed, no active ulceration, thin atrophic skin at prior ulcer sites

Hematology clinic, cytoreduction selection

Hematologist-Oncologist Opening

Hydroxyurea is still the guideline first-line agent here, and healed ulcers aren't an absolute contraindication — with real dermatologic surveillance and a low threshold to stop at the first new lesion, it's reasonable to try it first and reserve ruxolitinib, which RESPONSE actually studied in hydroxyurea-resistant or -intolerant patients, for if that surveillance catches a real problem.

Clinical Pharmacologist Response

I'd read that differently. This isn't a population-level cutaneous-toxicity rate we're weighing against an average patient's risk — it's a specific, documented vulnerability in the exact tissue hydroxyurea is known to damage, in a man who spent five years fighting to close those same wounds. Waiting for a new ulcer to confirm the mechanism means accepting a real, possibly slow-healing injury as the cost of finding out something already predictable.

Surveillance catches a new ulcer after it starts, not before — by the time it's visible, the tissue damage that will take months to heal has already happened.

Primary Care Physician Final

There's a way to avoid the whole tradeoff. Pegylated interferon alfa-2a has real comparative data against hydroxyurea from PROUD-PV and its extension — similar cytoreductive effectiveness, and it doesn't carry hydroxyurea's cutaneous liability at all. It has its own real cost: flu-like symptoms, occasional mood effects, weekly injections instead of a daily pill. But it doesn't ask him to bet his legs on surveillance catching a problem in time.

Regimen selected
Pegylated Interferon Alfa-2a
Immunomodulator, JAK2-Directed Cytoreduction · Weekly subcutaneous
Selected given PROUD-PV/CONTINUATION-PV's comparable cytoreductive efficacy to hydroxyurea, without hydroxyurea's cutaneous ulcer risk in a patient with a documented history in exactly that tissue.
Hydroxyurea — Ruled Out (First-Line)
Ribonucleotide Reductase Inhibitor
Guideline-standard first agent, but judged an unacceptable first move given his specific, recent history of severe venous leg ulceration — the exact toxicity this drug is best documented to cause or worsen.
Ruxolitinib — Held in Reserve
JAK1/2 Inhibitor
Named explicitly as the next step if interferon is not tolerated or insufficiently effective — its RESPONSE-trial evidence base is for hydroxyurea-resistant/intolerant disease, which he would then formally be.
Aspirin 81mg daily + Therapeutic Phlebotomy
Antiplatelet / Procedural · Continued
Continued as foundational PV management alongside whichever cytoreductive agent is chosen.
Where this was left

Agreed: start pegylated interferon alfa-2a as first cytoreductive agent, continuing phlebotomy and aspirin, with dermatology follow-up to monitor the healed ulcer sites regardless of which drug he's on.

Not agreed: the hematologist-oncologist's preference for a hydroxyurea trial with surveillance. The real limitation here isn't his argument, it's the guideline itself — its ordering is built from population-level toxicity data with no place to record one man's own healed leg ulcers, and a sequencing guideline built that way will keep recommending hydroxyurea first for patients exactly like him unless someone in the room already knows his history.

Educational content only — a composite teaching case, not a real patient encounter or a substitute for clinical guidance. About These Cases →