Balancing the good and the bad: controlling immune related adverse events versus anti-tumor responses in cancer patients treated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have provided new hope for cancer patients, and in particular for patients with tumors that are immunologically active and classified as hot tumors. These tumors express antigenic and tumor microenvironment (TME) characteristics that make them potential candidates for therapy with checkpoint inhibitors that aim to reactivate the immune response such as anti-PD-1 and anti-CTLA-4. Examples of potentially responsive cancers are, melanoma, non-small cell lung cancer and several other metastatic or unresectable tumors with genetic instability: DNA mismatch repair deficiency (dMMR), microsatellite instability-high (MSI-H), or with a high tumor mutational burden (TMB). Immunotherapy using checkpoint inhibitors is typically associated with adverse events (AEs) that are milder than those with chemotherapy. However, a significant percentage of patients develop short-term immune-related AEs (irAEs) which range from mild (~70%) to severe cases (~13%) that can lead to modifications of the checkpoint inhibitor therapy and in some cases, death. While some studies have investigated immune mechanisms behind the development of irAEs, much more research is needed to understand the mechanisms and to develop interventions that could attenuate severe irAEs, while maintaining the anti-tumor response intact. Moreover, studies to identify biomarkers that can predict the likelihood of a patient developing severe irAEs would be of great clinical importance. Here we discuss some of the clinical ramifications of irAEs, potential immune mechanisms behind their development and studies that have investigated potentially useful biomarkers of irAEs development.

Current approaches to immunotherapy in noncolorectal gastrointestinal malignancies

Noncolorectal gastrointestinal (GI) malignancies are among the most frequently diagnosed cancers. Despite the undeniable progress in systemic treatments in recent decades, further improvements using cytotoxic chemotherapy seem unlikely. In this setting, recent discoveries regarding the mechanism underlying immune evasion have prompted the study of molecules capable of inducing strong antitumor responses. Thus, according to early data, immunotherapy is a very promising tool for the treatment of patients with GI malignancies. Noncolorectal GI cancers are a major public health problem worldwide. Traditional treatment options, such as chemotherapy, surgery, radiation therapy, monoclonal antibodies and antiangiogenic agents, have been the backbone of treatment for various stages of GI cancers, but overall mortality remains a major problem. Thus, there is a substantial unmet need for new drugs and therapies to further improve the outcomes of treatment for noncolorectal GI malignancies. "Next-generation" immunotherapy is emerging as an effective and promising treatment option in several types of cancers. Therefore, encouraged by this recent success, many clinical trials evaluating the efficacy of immune checkpoint inhibitors and other strategies in treating noncolorectal GI malignancies are ongoing. This review will summarize the current clinical progress of modern immunotherapy in the field of noncolorectal GI tumors.

Tuberculosis in a patient on temozolomide: a case report

Temozolomide (TMZ) is a cytotoxic agent of the imidazotetrazine class, chemically related to dacarbazine. Its use poses higher risks of lymphopenia and opportunistic infections. Prophylaxis for Pneumocystis jiroveci must be considered up to 12 months after treatment discontinuation. The due literature (MEDLINE) makes no mention of a possible connection between the use of TMZ and tuberculosis (TB). A female patient, aged 59, featuring glioblastoma multiforme and having undergone solely a brain biopsy, was submitted to TMZ along with radiotherapy. After the first TMZ maintenance cycle, the referred patient was admitted displaying a background of a 40-day afternoon fever and productive coughing. She was thus submitted to a bronchoscopy and LBA, which resulted BAAR 1+/4+. TMZ was then suspended, and rifampicin, isoniazid, and pyrazinamide introduced. Considerations on prophylaxis with isoniazide in cancer patients are long-lived and scarce. Some subgroups are likely to benefit from the prophylactic administration of isoniazide during TMZ treatment, such as those patients under high doses of corticoids, patients with past medical history of TB, the malnourished, patients from endemic regions, and patients with highly reactive tuberculinic tests. That, nevertheless, must not restrict the administration of TMZ, but, rather, stand for a warning about its possible toxicity, and thus mitigate complications.