Delayed hypersensitivity and cytokine release syndrome to paclitaxel and nab-paclitaxel: a case report

Hypersensitivity reactions (HSRs) to paclitaxel, particularly those mediated by the solubilizer Cremophor® EL, are common, occurring in approximately 10% of patients despite premedication. Nab-paclitaxel, a newer formulation using human serum albumin as the vehicle, is generally considered a safer alternative due to a lower rate of HSRs. We present the case of a 44-year-old woman with breast cancer who developed severe HSRs following multiple doses of paclitaxel and carboplatin. Despite standard premedication, she experienced fever, erythematous skin eruptions, arthralgias, and systemic symptoms following her fourth and fifth cycles of treatment. Subsequent administration of nab-paclitaxel also elicited a similar severe reaction. Skin testing revealed a positive reaction to paclitaxel, but not to carboplatin, suggesting sensitization to paclitaxel. In the context of the similar reaction to nab-paclitaxel, this suggests sensitization to the taxane moiety itself rather than to the solubilizer. The combination of features consistent with both type IV hypersensitivity and cytokine release syndrome further complicates the presentation as well. To our knowledge, this is the first reported case of cross-reactivity between paclitaxel and nab-paclitaxel, challenging the assumption that nab-paclitaxel is always a safe alternative. This emphasizes the need for vigilance and thorough evaluation in patients experiencing atypical chemotherapy reactions, as cytokine release reactions may play a role even in the absence of immunotherapy. It also raises the concern that alternative formulations like nab-paclitaxel may not always be safe in patients with atypical or severe reactions, as they could possibly be sensitized to the taxane moiety itself.