ITP caused by immune checkpoint inhibitors (ICIs) is rare (0.25% incidence) but generally has a good prognosis. Most patients respond to standard first-line ITP therapies, and approximately 70% of those re-challenged with the ICI can continue treatment without a recurrence of ITP.
Unlike immunotherapy, where re-challenge after progression is dubious, there is an emerging clinical practice of re-challenging patients with the same antibody-drug conjugate (ADC), such as enfortumab vedotin (EV), after a treatment break forced by toxicity. Anecdotally, patients are showing great responses, highlighting a key area for prospective data generation.
Contrary to initial concerns, long-term safety data for thrombopoietin receptor agonists has allayed fears of malignant transformation and irreversible bone marrow fibrosis. The increased reticulin fibrosis observed is reversible upon drug discontinuation, offering significant reassurance for long-term prescribing.
Beyond raising platelet counts, the newly approved BTK inhibitor rilzabrutinib provides dramatic improvements in the fatigue associated with ITP. This unique benefit, likely due to its anti-inflammatory properties, makes it a strong consideration for patients where fatigue is a primary quality of life issue.
The treatment paradigm for ITP is shifting towards early combination therapy. Recent clinical trials are investigating augmented first- and second-line regimens, such as combining dexamethasone with rituximab or romiplostim, to achieve more durable, treatment-free responses than monotherapy.
Patients with ITP who fail or are intolerant to one TPO receptor agonist (e.g., eltrombopag) should not be considered a class failure. Switching to another TPO agent is a viable strategy that can induce a response in nearly half of these cases, particularly for intolerance.
For endometrial or cervical cancer patients who progress after receiving a checkpoint inhibitor, re-challenging with a single-agent immunotherapy is a less desirable approach. Emerging data suggests that a combination therapy—such as an ICI paired with a TKI like lenvatinib or a bispecific antibody—offers a more promising chance of response.
For patients who previously received immunotherapy (IO), a recurrence more than 12 months after completing treatment makes re-challenging with an IO agent a reasonable option. The likelihood of benefit is lower if the recurrence is within 6-12 months and minimal if under 6 months.
Historical data showing high cure rates for splenectomy in ITP is outdated. Recent data indicates that if a patient has already failed both a TPORA and rituximab, the chance of a successful splenectomy is less than 50%, repositioning it as a later-line salvage option.
Named after the two-faced god Janus, yanalumab has a dual mechanism. It acts as a highly potent B-cell depleter while also blocking the BAF receptor pathway, which is critical for auto-reactive B-cell survival. This offers potential for deep, lasting, treatment-free remission.
In cases of severe ITP unresponsive to standard therapies, the anti-CD38 monoclonal antibody daratumumab can be highly effective. It works by eliminating the long-lived plasma cells responsible for secreting platelet autoantibodies, a mechanism distinct from other ITP treatments.