Serious Infections in Patients Receiving Ibrutinib for Treatment of Lymphoid Cancer

A pilot study of lower doses of ibrutinib in patients with chronic lymphocytic leukemia

Ibrutinib is highly efficacious and used at 420 mg/d for treatment of chronic lymphocytic leukemia (CLL). We previously demonstrated a decline in Bruton's tyrosine kinase (BTK) protein levels in CLL cells after 1 cycle of ibrutinib, suggesting ibrutinib dose could be lowered after the first cycle without loss of biological effect. To test this postulate, a pilot study (NCT02801578) was designed to systematically reduce ibrutinib dosing within the same patient with CLL over the course of three 28-day cycles. After an initial cycle of 420 mg/d, the dose was reduced to 280 mg/d in cycle 2, and then to 140 mg/d in cycle 3. Eleven patients began study treatment, and 9 completed the 3 cycles. Plasma and intracellular pharmacokinetics (PK), BTK occupancy, and pharmacodynamic (PD) response at different doses of ibrutinib were compared. Plasma and intracellular levels of ibrutinib were dose-dependent, and even the lowest dose was sufficient to occupy, on average, more than 95% of BTK protein. In concert, BTK downstream signaling inhibition was maintained with 140 mg/d ibrutinib in cycle 3, and there were comparable reductions in total and phospho-BTK (Tyr223) protein levels across 3 cycles. Reductions of plasma chemokine CCL3 and CCL4 levels, considered to be biomarkers of ibrutinib response, were similar during the 3 cycles. These PK/PD data demonstrate that after 1 cycle of ibrutinib at the standard 420 mg/d dose, the dose can be reduced without losing biological activity. Clinical efficacy of lower doses needs to be systematically evaluated. Such dose reductions would lower drug cost, lessen untoward toxicity, and facilitate rationale-based combinations. This trial was registered at www.clinicaltrials.gov as #NCT02801578.

Invasive Fungal Infections in Patients with Chronic Lymphoproliferative Disorders in the Era of Target Drugs

This review summarizes the more recent evidence about epidemiology and risk factors for invasive fungal infections (IFI) in patients affected by Chronic Lymphocytic Leukemia (CLL), indolent Non Hodgkin Lymphoma (iNHL) and Multiple Myeloma (MM). Despite advances in the prognosis and treatment of hematological malignancies in recent years, susceptibility to infection remains a significant challenge to patient care. A large amount of data regarding patients with acute leukemia has been published while little information is available on the incidence of IFI in chronic lymphoproliferative disorders (CLD). New drugs are now available for treatment of lymphoproliferative disorders which may cause suppression of humoral immunity, cellular immunity, and deficiency of white blood cells, increasing the risk for infections which remain the leading cause of mortality in these patients.

Cerebral aspergillosis in a patient on ibrutinib therapy-A predisposition not to overlook

Ibrutinib has revolutionized the treatment of B-cell malignancies since its approval for chronic lymphocytic leukemia. It is also used in mantle cell lymphoma, diffuse large B-cell lymphoma, Waldenstrom's macroglobulinemia, among others. It is a Bruton's tyrosine kinase inhibitor that acts on B-cell receptor signaling pathway and predisposes to various infections due to its effects on neutrophils, monocytes and T cells. We present a case of cerebral invasive aspergillosis in a patient being treated with ibrutinib for relapsed chronic lymphocytic leukemia. It was hard to associate the condition to ibrutinib versus the chronic lymphocytic leukemia. The patient was successfully treated with a combination of voriconazole and micafungin, resulting in complete recovery and no residual deficits. This highlights the importance of recognizing the rare complication in those on ibrutinib and initiating the treatment immediately with appropriate antifungal agents to improve prognosis of this potentially fatal condition.

Ibrutinib Therapy and Mycobacterium chelonae Skin and Soft Tissue Infection

Ibrutinib is an irreversible inhibitor of Bruton’s tyrosine kinase approved for the treatment of B-cell malignancies. There is growing concern about the risk of opportunistic infections following ibrutinib therapy. Herein, we describe the first case of Mycobacterium chelonae skin and soft tissue infection in a patient receiving ibrutinib and recount the challenges in treating this infection.

Cryptococcal meningoencephalitis in patients with mantle cell lymphoma on ibrutinib

Ibrutinib, a Bruton's tyrosine kinase inhibitor, has been increasingly widely used in relapsed and refractory mantle cell lymphoma (MCL) and chronic lymphocytic leukaemia [1, 2]. With its use becoming more common, there have been emerging case reports of opportunistic infections like cryptococcal infections [3-8]. These infections in patients receiving ibrutinib were mostly reported in patients with chronic lymphocytic leukaemia, who have poor immune reconstitution. Here, we report two cases of cryptococcal meningoencephalitis in patients with MCL on ibrutinib.