A RIPK1-specific PROTAC degrader achieves potent antitumor activity by enhancing immunogenic cell death.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a critical stress sentinel that coordinates cell survival, inflammation, and immunogenic cell death (ICD). Although the catalytic function of RIPK1 is required to trigger cell death, its non-catalytic scaffold function mediates strong pro-survival signaling. Accordingly, cancer cells can hijack RIPK1 to block necroptosis and evade immune detection. We generated a small-molecule proteolysis-targeting chimera (PROTAC) that selectively degraded human and murine RIPK1. PROTAC-mediated depletion of RIPK1 deregulated TNFR1 and TLR3/4 signaling hubs, accentuating the output of NF-κB, MAPK, and IFN signaling. Additionally, RIPK1 degradation simultaneously promoted RIPK3 activation and necroptosis induction. We further demonstrated that RIPK1 degradation enhanced the immunostimulatory effects of radio- and immunotherapy by sensitizing cancer cells to treatment-induced TNF and interferons. This promoted ICD, antitumor immunity, and durable treatment responses. Consequently, targeting RIPK1 by PROTACs emerges as a promising approach to overcome radio- or immunotherapy resistance and enhance anticancer therapies.

Targeting myeloid chemotaxis to reverse prostate cancer therapy resistance.

Inflammation is a hallmark of cancer1. In patients with cancer, peripheral blood myeloid expansion, indicated by a high neutrophil-to-lymphocyte ratio, associates with shorter survival and treatment resistance across malignancies and therapeutic modalities2-5. Whether myeloid inflammation drives progression of prostate cancer in humans remain unclear. Here we show that inhibition of myeloid chemotaxis can reduce tumour-elicited myeloid inflammation and reverse therapy resistance in a subset of patients with metastatic castration-resistant prostate cancer (CRPC). We show that a higher blood neutrophil-to-lymphocyte ratio reflects tumour myeloid infiltration and tumour expression of senescence-associated mRNA species, including those that encode myeloid-chemoattracting CXCR2 ligands. To determine whether myeloid cells fuel resistance to androgen receptor signalling inhibitors, and whether inhibiting CXCR2 to block myeloid chemotaxis reverses this, we conducted an investigator-initiated, proof-of-concept clinical trial of a CXCR2 inhibitor (AZD5069) plus enzalutamide in patients with metastatic CRPC that is resistant to androgen receptor signalling inhibitors. This combination was well tolerated without dose-limiting toxicity and it decreased circulating neutrophil levels, reduced intratumour CD11b+HLA-DRloCD15+CD14- myeloid cell infiltration and imparted durable clinical benefit with biochemical and radiological responses in a subset of patients with metastatic CRPC. This study provides clinical evidence that senescence-associated myeloid inflammation can fuel metastatic CRPC progression and resistance to androgen receptor blockade. Targeting myeloid chemotaxis merits broader evaluation in other cancers.

Effect of Reasons for Screen Failure on Subsequent Treatment Outcomes in Cancer Patients Assessed for Clinical Trials.

INTRODUCTION: The cancer research community increasingly question the rigidity of eligibility criteria in clinical trials. Common reasons for "screen failure" (RFSF) are well documented; however, their effect on subsequent standard therapy (SST) and outcomes is unclear. METHODS: This retrospective study evaluated patients aged ≥18 years with solid malignancy who were listed as ineligible on a screening log between February 2011 and March 2018. Patients screen-failed for biomarker results or incorrect cancer stage/prior treatment profile were excluded. Data were collected from electronic hospital records, including demographics, cancer history, RFSF, subsequent therapy, and outcomes. RESULTS: Overall, 217 patients were eligible. The most common histologies were lung (28%), melanoma, colon, and pancreatic (all 11%); 90% were metastatic. The most common RFSF were rapid disease progression (PD; 16%), performance status (PS) ≥2 (12%), and abnormal liver function tests (aLFT; 12%). After screen failure, 129/217 (59%) had SST; 9 were dose-reduced. Treatment-naïve or phase III trial-ineligible patients were more likely to receive SST than those pre-treated or phase I trial-ineligible (72/104 vs. 52/113, p = 0.0006; 71/109 vs. 15/42, p = 0.00013), respectively. RFSF stabilised/improved in 104/217 (48%); the main RFSF was co-morbidity (19/104). The most common RFSF to deteriorate were rapid PD (27/72), PS ≥2 (20/72), and aLFT with liver metastases (LM; 13/72). CONCLUSIONS: RFSF related to organ function rarely deteriorate unless directly involved with underlying malignancy. Most RFSF do not prevent patients from having SST, nor increase dose reductions, especially in treatment-naïve/phase III trial-ineligible patients. Those with RFSF of poor PS, rapid PD, and aLFT from LM are less suitable for SST. Careful broadening of trial eligibility is warranted.

Moving beyond epidermal growth factor receptor resistance in metastatic non-small cell lung cancer - a drug development perspective.

Epidermal Growth Factor Receptor (EGFR) mutations are the most common targetable oncogenic driver mutation in metastatic non-small lung cancer (NSCLC). There have been significant advances in the management of metastatic EGFR-mutant NSCLC from the advent of first and second generation EGFR inhibitors to, more recently, the third-generation inhibitor osimertinib. Osimeritinib is now established as first-line therapy on the basis of improved outcomes compared to first and second generation agents. However, despite excellent initial response rates, responses may not be durable due to the development of acquired resistance. Understanding these mechanisms of resistance is critical to the development of rational drug and drug combinations capable of circumventing them. We discuss the major mechanisms of resistance to first, second and third generation EGFR TKIs. The potential of drug combinations utilising chemotherapy, immunotherapy and anti-angiogenic drugs are explored. We examine strategies to aid drug development, including circulating tumour DNA and novel trial designs.

A Wolf in Sheep's Clothing: Systemic Immune Activation Post Immunotherapy.

Introduction: Immune checkpoint inhibitors (ICIs) are increasingly a standard of care for many cancers; these agents can result in immune-related adverse events (irAEs) including fever, which is common but can rarely be associated with systemic immune activation (SIA or acquired HLH). Methods: All consecutive patients receiving ICIs in the Drug Development Unit of the Royal Marsden Hospital between May 2014 and November 2019 were retrospectively reviewed. Patients with fever ≥ 38°C or chills/rigors (without fever) ≤ 6 weeks of commencing ICIs were identified for clinical data collection. Results: Three patients met diagnostic criteria for SIA/HLH with median time to onset of symptoms of 10 days. We describe the clinical evolution, treatment used, and outcomes for these patients. High-dose steroids are used first-line with other treatments, such as tocilizumab, immunoglobulin and therapeutic plasmapheresis can be considered for steroid-refractory SIA/HLH. Conclusion: SIA/HLH post ICI is a rare but a potentially fatal irAE that presents with fever and a constellation of nonspecific symptoms. Early recognition and timely treatment are key to improving outcomes.

Research Related Tumour Biopsies in Early-Phase Trials with Simultaneous Molecular Characterisation - a Single Unit Experience.

Early-phase cancer clinical trials are becoming increasingly accessible for patients with advanced cancer who have exhausted standard treatment options and later phase trial options. Many of these trials mandate research tissue biopsies. Research biopsies have been perceived as ethically fraught due to the perception of potential coercion of vulnerable human subjects. We performed an audit of two years of practice to assess the safety of ultrasound (US)-guided research biopsies, and to look at the yield of a simultaneous tumour next-generation sequencing (NGS) and immunohistochemistry (IHC) molecular characterisation programme. We show that in our institution, US-guided research biopsies were safe, produced adequate tumour content and in a selected subset who underwent in-house NGS sequencing, showed a high rate of actionable mutations with 30% having a Tier 1 variant. Nevertheless, these research biopsies may only provide direct benefit for a minority of patients and we conclude with a reflection on the importance of obtaining truly informed consent.

Radiological Patterns of Drug-induced Interstitial Lung Disease (DILD) in Early-phase Oncology Clinical Trials.

PURPOSE: Drug-induced interstitial lung disease (DILD) is a rare, but potentially fatal toxicity. Clinical and radiological features of DILD in the early experimental setting are poorly described. PATIENTS AND METHODS: A total of 2,499 consecutive patients with advanced cancer on phase I clinical trials were included. DILD was identified by a dedicated radiologist and investigators, categorized per internationally recognized radiological patterns, and graded per Common Terminology Criteria for Adverse Events (CTCAE) and the Royal Marsden Hospital (RMH) DILD score. Clinical and radiological features of DILD were analyzed. RESULTS: Sixty patients overall (2.4%) developed DILD. Median time to onset of DILD was 63 days (range, 14-336 days). A total of 45% of patients who developed DILD were clinically asymptomatic. Incidence was highest in patients receiving drug conjugates (7.4%), followed by inhibitors of the PI3K/AKT/mTOR pathway (3.9%). The most common pattern seen was hypersensitivity pneumonitis (33.3%), followed by nonspecific interstitial pneumonia (30%), and cryptogenic organizing pneumonia (26.7%). A higher DILD score [OR, 1.47, 95% confidence interval (CI), 1.19-1.81; P < 0.001] and the pattern of DILD (OR, 5.83 for acute interstitial pneumonia; 95% CI, 0.38-90.26; P = 0.002) were significantly associated with a higher CTCAE grading. The only predictive factor for an improvement in DILD was an interruption of treatment (OR, 0.05; 95% CI, 0.01-0.35; P = 0.01). CONCLUSIONS: DILD in early-phase clinical trials is a toxicity of variable onset, with diverse clinical and radiological findings. Radiological findings precede clinical symptoms. The extent of the affected lung parenchyma, scored by the RMH DILD score, correlates with clinical presentation. Most events are low grade, and improve with treatment interruption, which should be considered early.

Outcomes of Australian patients receiving non-funded anti-PD-1 immune checkpoint inhibitors for non-melanoma cancers.

AIM: To characterize the outcomes of patients with nonmelanoma solid tumors receiving anti-PD-1 immunotherapy not funded by the Australian Pharmaceutical Benefits Scheme. METHODS: Medical records of patients with metastatic nonmelanoma tumor diagnoses treated with anti-PD-1 (self-funded pembrolizumab or nivolumab through an access program) from January 1, 2014, to December 31, 2016, at Peter MacCallum Cancer Centre, were retrospectively reviewed. Events after December 31, 2016, were censored. RESULTS: Of 47 patients identified, 27 (57%) had lung cancer. Twenty-six had compassionate access to nivolumab (24 lung, one renal, one gastroesophageal with possible new lung primary). Median overall survival was 5.7 months. Eleven (23%) achieved a partial response; none had complete response. Twenty (43%) had disease progression on first imaging; 16 (48%) of these continued treatment beyond radiological progression, with three achieving subsequent partial responses. Ten (21%) were not re-staged mostly due to rapid deterioration or death. At 6 and 12 months, nine (20%) and two (4%) remained on treatment, respectively. Five (12%) discontinued treatment due to immune-related toxicities. Of 34 patients who died, 71% received treatment within the last month of life; 38% died in an acute hospital. None of 25 patients with poor Eastern Cooperative Oncology Group performance scores of 2-4 responded. CONCLUSION: The response rates and overall survival of patients with NSCLC, renal carcinoma and triple negative breast cancer of good performance status receiving anti-PD-1 therapy outside of a clinical trial are consistent with clinical trial data. However, patients with poor ECOG performance status are unlikely to respond. Careful patient selection and counseling about the potential outcomes of self-funding treatment in this setting is needed.

Early recognition of ipilimumab-related autoimmune hypophysitis in patients with metastatic melanoma: Case studies and recommendations for management.

Ipilimumab is a human anti-CTLA-4 monoclonal antibody recently approved for the treatment of advanced melanoma. Stimulation of T-cell activity unmasks antitumor activity, but can cause immune-related adverse events. Autoimmune hypophysitis is of particular importance because its presentation can be subtle but life threatening. We present two cases where early recognition of ipilimumab-related autoimmune hypophysitis led to timely intervention and low subsequent morbidity, without compromise of antitumor effects. We provide recommendations for detection and management of this potentially life-threatening complication of ipilimumab.