Bleomycin is a chemotherapy drug derived from bacteria, used primarily to treat testicular cancer, Hodgkin’s lymphoma, and certain squamous cell carcinomas. First approved by the FDA in 1975, it remains a key part of several standard cancer treatment regimens and has some notable uses outside of oncology as well. What makes bleomycin unusual among chemotherapy drugs is its unique mechanism: it directly cuts strands of DNA, and it carries a specific risk of lung damage that requires careful monitoring before, during, and after treatment.
Where Bleomycin Comes From
Bleomycin is a natural product, originally isolated from soil bacteria. In 1957, a Japanese researcher named Hamao Umezawa began a program at the Institute for Microbial Chemistry in Tokyo searching for anticancer compounds produced by microbes. By 1962, his team had identified an active substance made by a bacterium called Streptomyces verticillus, part of the same family that had already yielded several antibiotics. The purified material became bleomycin, which is actually a mixture of closely related chemical variants, with two forms (A2 and B2) making up the bulk of what’s used clinically.
How Bleomycin Damages Cancer Cells
Most chemotherapy drugs interfere with cell division in indirect ways. Bleomycin is more direct: it physically breaks DNA strands. To do this, the drug needs to combine with iron and oxygen inside the cell. Once activated by iron, bleomycin latches onto specific sites in the DNA double helix and pulls a hydrogen atom off the sugar backbone of the strand. This breaks the strand apart. The drug can cause both single-strand and double-strand breaks, and double-strand breaks are especially lethal to cells because they’re much harder to repair.
Bleomycin preferentially targets certain DNA sequences, particularly spots where a guanine sits next to a thymine or cytosine. This selectivity is part of what gives the drug its anticancer activity, though it also means bleomycin can damage DNA in healthy cells, which accounts for its side effects.
Cancers Treated With Bleomycin
Bleomycin is FDA-approved for use against several types of cancer. The most common include testicular cancer, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, and squamous cell cancers of the head, neck, and cervix. It’s also approved for nasopharyngeal cancer, gestational trophoblastic disease, and certain germ cell tumors.
In testicular cancer, bleomycin is part of the well-known BEP regimen (bleomycin, etoposide, and cisplatin), which is one of the most successful chemotherapy combinations in all of oncology, curing the majority of patients even with advanced disease. In Hodgkin’s lymphoma, it appears in the ABVD regimen alongside three other drugs. In both cases, bleomycin’s role is considered essential to the regimen’s effectiveness.
Use for Stubborn Warts
Outside of cancer treatment, bleomycin is sometimes injected directly into warts that haven’t responded to other therapies. This use is not FDA-approved, but dermatologists have employed it for decades against warts on the hands, feet, and around the nails. The drug is diluted to a low concentration (typically 1 mg/mL) and injected in small volumes directly into the wart tissue, usually requiring only one or two sessions spaced two weeks apart.
The results can be striking. In one controlled study, bleomycin injections cleared over 96% of warts on the palms, soles, and around the nails, compared to about 11% clearance with placebo injections. Warts around the nails responded at a 100% cure rate. The treatment works because bleomycin destroys the rapidly dividing cells in the wart without significant absorption into the rest of the body.
Pulmonary Toxicity: The Major Risk
The most serious side effect of bleomycin is lung damage, known as bleomycin pulmonary toxicity. Unlike most organs, the lungs have very low levels of the enzyme that breaks bleomycin down, which means the drug accumulates in lung tissue more than anywhere else in the body. Over time, this can cause inflammation and scarring (fibrosis) that permanently reduces lung function.
The risk rises with the total amount of bleomycin a person receives over their lifetime. Cumulative doses above 400 to 450 units are considered a major risk factor, and most treatment protocols set a lifetime cap of 400 units. But lung damage can occur at lower doses too, especially if other risk factors are present: age over 40, kidney problems, prior chest radiation, or simultaneous treatment with certain other chemotherapy drugs like cisplatin or cyclophosphamide.
During treatment, doctors monitor lung function regularly. The key test measures how efficiently the lungs transfer oxygen from inhaled air into the bloodstream. If that measurement drops by 25% or more compared to the pre-treatment baseline, bleomycin is typically discontinued to prevent further damage.
The Oxygen Precaution
One of the most unusual aspects of bleomycin is its long-term interaction with supplemental oxygen. Even months or years after treatment ends, patients who have received bleomycin face increased risk of lung injury if they’re exposed to high concentrations of oxygen, such as during surgery under general anesthesia or hyperbaric oxygen therapy. Cases of lung toxicity and death have been reported after exposure to only modestly elevated oxygen levels during operations.
For this reason, anyone with a history of bleomycin treatment who needs surgery or emergency oxygen should keep their oxygen levels as low as possible while still maintaining adequate tissue oxygenation. This is a lifelong consideration, and patients are generally advised to carry medical identification noting their bleomycin exposure so that anesthesiologists and emergency teams are aware.
Flagellate Erythema: A Distinctive Skin Reaction
Bleomycin can cause a skin reaction that looks like nothing else in medicine. Called flagellate erythema, it produces a pattern of red, linear streaks across the body that look as though the person has been whipped. The streaks are formed by rows of small, firm bumps that merge into lacy, intermingled lines. The rash typically starts with itching, followed by the appearance of the red streaks. Over time, the redness fades and leaves behind darkened lines of post-inflammatory pigmentation.
This reaction occurs in roughly 8% to 22% of patients receiving bleomycin. While it looks alarming, it generally resolves on its own after the drug is stopped, though the skin discoloration can linger. Small areas of pinpoint bleeding or pustules sometimes accompany the streaks. The pattern is so characteristic that it can actually help confirm bleomycin as the cause when a patient develops an unexplained rash during treatment.
Other Side Effects
Beyond the lungs and skin, bleomycin is notable for what it doesn’t do compared to many other chemotherapy drugs. It causes relatively little bone marrow suppression, meaning it’s less likely to severely lower blood cell counts. This is one reason it works well in combination regimens, where it adds anticancer activity without compounding the blood count problems caused by the other drugs in the mix.
Common side effects include fever (sometimes with chills shortly after administration), mouth sores, loss of appetite, and nail changes. Some patients experience hair thinning, though typically less severe than with other chemotherapy agents. Skin thickening and darkening on the hands and feet can also occur, particularly at pressure points.