Recurrent non-melanoma skin cancers in patients on ruxolitinib may be attributable to its JAK1 inhibition. In such cases, a viable strategy is to switch the patient to a more JAK2-selective inhibitor, such as pacritinib or fedratinib, to potentially mitigate this specific side effect while maintaining disease control.
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Due to fedratinib's significant GI side effect profile and the logistical difficulty of measuring thiamine levels, clinicians should proactively provide patients with thiamine supplements, anti-emetics, and anti-diarrheal therapies. Instructing patients to take the drug with food can also help mitigate GI toxicity.
Despite subsequent data not confirming an increased bleeding risk compared to other therapies, the initial studies on pacritinib showed a signal for increased bleeding. Consequently, it is still advised that the drug be stopped for several days prior to any major surgical procedure as a safety precaution.
The failure of an adjuvant trial for the TKI pazopanib was likely caused by a protocol change that reduced the dose to manage transaminitis. While well-intentioned to improve tolerability and adherence, the lower dose was sub-therapeutic. This serves as a critical lesson that managing side effects by compromising dose can nullify a drug's potential efficacy.
Clinicians can reassure myelofibrosis patients that the drop in hemoglobin often seen when starting ruxolitinib does not carry the same negative prognostic weight as anemia caused by the disease itself. This distinction is crucial for managing patient expectations and continuing effective therapy despite initial side effects.
While beneficial for patients with prior weight loss, ruxolitinib can cause significant weight gain (20-30 pounds) in other myelofibrosis patients. This quality-of-life issue should be discussed proactively, as it can become a major concern, effectively trading one disease state for another.
For myelofibrosis patients with profound splenomegaly but only moderate thrombocytopenia (platelets 50k-100k), fedratinib may be the best frontline option. It is arguably the most potent JAK inhibitor for spleen reduction and is approved for use in patients with platelet counts as low as 50,000.
For myelofibrosis patients with both anemia and splenomegaly, a practical approach is to start with ruxolitinib for its superior symptom control. If the subsequent anemia is not well-tolerated, switching to momelotinib allows for a more informed, personalized decision based on the patient's experience with both agents.
While pirtobrutinib is effective after covalent BTK inhibitors, the reverse is unproven. Starting with pirtobrutinib frontline raises a critical unanswered question about whether patients will still respond to older covalent inhibitors, complicating sequencing decisions, especially for younger patients.
The development of new KIT inhibitors like bezuclastinib is largely fueled by the need for alternatives to high-dose avapritinib in advanced SM. Concerns about cognitive effects and rare intracranial hemorrhage with avapritinib create an opportunity for agents with less blood-brain barrier penetration.
CLL-associated immunosuppression dramatically increases the risk and aggressiveness of skin cancers. This risk is not mitigated by novel therapies, and in some cases, the secondary skin malignancy can become a greater threat to a patient's life than their underlying CLL.