Baseline gut microbiota predicts clinical response and colitis in metastatic melanoma patients treated with ipilimumab

Background

Ipilimumab, an immune checkpoint inhibitor targeting CTLA-4, prolongs survival in a subset of patients with metastatic melanoma (MM) but can induce immune-related adverse events, including enterocolitis. We hypothesized that baseline gut microbiota could predict ipilimumab anti-tumor response and/or intestinal toxicity.

Patients and methods

Twenty-six patients with MM treated with ipilimumab were prospectively enrolled. Fecal microbiota composition was assessed using 16S rRNA gene sequencing at baseline and before each ipilimumab infusion. Patients were further clustered based on microbiota patterns. Peripheral blood lymphocytes immunophenotypes were studied in parallel.

Results

A distinct baseline gut microbiota composition was associated with both clinical response and colitis. Compared with patients whose baseline microbiota was driven by Bacteroides (cluster B, n = 10), patients whose baseline microbiota was enriched with Faecalibacterium genus and other Firmicutes (cluster A, n = 12) had longer progression-free survival (P = 0.0039) and overall survival (P = 0.051). Most of the baseline colitis-associated phylotypes were related to Firmicutes (e.g. relatives of Faecalibacterium prausnitzii and Gemmiger formicilis), whereas no colitis-related phylotypes were assigned to Bacteroidetes. A low proportion of peripheral blood regulatory T cells was associated with cluster A, long-term clinical benefit and colitis. Ipilimumab led to a higher inducible T-cell COStimulator induction on CD4+ T cells and to a higher increase in serum CD25 in patients who belonged to Faecalibacterium-driven cluster A.

Conclusion

Baseline gut microbiota enriched with Faecalibacterium and other Firmicutes is associated with beneficial clinical response to ipilimumab and more frequent occurrence of ipilimumab-induced colitis.

Cancer Immunotherapy with Anti-CTLA-4 Monoclonal Antibodies Induces an Inflammatory Bowel Disease

BACKGROUND

Therapeutic monoclonal anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibodies are associated with immune-mediated enterocolitis. The aim of this study was to provide a detailed description of this entity.

METHODS

We included patients with endoscopic signs of inflammation after anti-CTLA-4 infusions for cancer treatment. Other causes of enterocolitis were excluded. Clinical, biological and endoscopic data were recorded. A single pathologist reviewed endoscopic biopsies and colectomy specimens from 27 patients. Patients with and without enterocolitis after ipilimumab-treated melanoma were compared, to identify clinical factors associated with enterocolitis.

RESULTS

Thirty-nine patients with anti-CTLA-4 enterocolitis were included (ipilimumab n = 37; tremelimumab n = 2). The most frequent symptom was diarrhoea. Ten patients had extra-intestinal manifestations. Most colonoscopies showed ulcerations involving the rectum and sigmoid, 66% of patients had extensive colitis, 55% had patchy distribution and 20% had ileal inflammation. Endoscopic colonic biopsies showed acute colitis in most patients, while half of the patients had chronic duodenitis. Thirty-five patients received steroids that led to complete clinical remission in 13 patients (37%). Twelve patients required infliximab, of whom 10 (83%) responded. Six patients underwent colectomy (perforation n = 5; toxic megacolon n = 1); one of them died postoperatively. Four patients had a persistent enterocolitis at follow-up colonoscopy. Patients with enterocolitis were more frequently prescribed NSAIDs compared with patients without enterocolitis (31 vs 5%, p = 0.003).

CONCLUSIONS

Ipilimumab and tremelimumab may induce a severe and extensive form of inflammatory bowel disease. Rapid escalation to infliximab should be advocated in patients who do not respond to steroids. Patients treated with anti-CTLA-4 should be advised to avoid NSAIDs.

Challenges of phase 1 clinical trials evaluating immune checkpoint-targeted antibodies

BACKGROUND

Immunostimulatory monoclonal antibodies (imAbs) targeting immune checkpoint molecules are revolutionizing oncology not only regarding cancer therapeutics and clinical care, but also from a drug development point of view. A handful of first-generation molecules have been approved so far based on their tremendous efficacy, after an expedited development phase that has challenged most paradigms established in the era of conventional cytotoxic therapy and to some extent molecularly targeted agents. A huge wave of second-generation imAbs is just entering into phase 1 trials now, in monotherapy or in combination. In order to maximize their chances of success in early phase trials, and eventually for patients' benefit, their clinical development has to benefit from lessons learnt from previous imAbs phase 1 trials.

MATERIALS AND METHODS

We reviewed the early clinical development of anti-cytotoxic T-lymphocyte antigen 4 and anti-programmed death-1 receptor/ligand. Particularities of each agent, including safety, dose--toxicity and dose--efficacy relationships, scheduling, pharmacokinetics (PK), pharmacodynamics (PD), trial design, biomarkers, response assessment and overall drug development strategies, are described and challenged.

RESULTS

As opposed to conventional cytotoxic agents, dose of imAbs is not linearly associated with efficacy and toxicity. Therefore, the definition of a minimal immunologically active dose could be proposed. Traditional patient eligibility criteria might also be revisited as the toxicity profile and mechanism of toxicity--immune-related adverse events--are mostly known and their physiopathology somehow less unexpected than with molecularly targeted small molecules. Most challenging are the comprehensive investigation of complex PK and PD characteristics as well as the definition of patient selection biomarkers. Finally, the early focus on efficacy (and not only dose confirmation) in expansion cohorts challenges the traditional phase 1/2/3 drug development process.

CONCLUSION

Several drug development paradigms have been challenged by imAbs. Here, we discuss novel approaches for an efficient and successful drug development of these agents.

Experience in daily practice with ipilimumab for the treatment of patients with metastatic melanoma: an early increase in lymphocyte and eosinophil counts is associated with improved survival

BACKGROUND

Ipilimumab is a recently approved immunotherapy that has demonstrated an improvement in the overall survival (OS) of patients with metastatic melanoma. We report a single-institution experience in patients treated in a compassionate-use program.

PATIENTS AND METHODS

In this prospective study, patients were treated between June 2010 and September 2011. Inclusion criteria were a diagnosis of unresectable stage III or IV melanoma, at least one previous line of chemotherapy, and survival 12 weeks after the first perfusion. Four courses of ipilimumab were administered at a dose of 3 mg/kg every 3 weeks.

RESULTS

Seventy-three patients were included. Median OS was 9.1 months (95% CI 6.4-11.3) from the start of ipilimumab. Immune-related adverse events were observed in 45 patients (62%), including 19 grade 3-4 events (26%). No drug-related death occurred. A lymphocyte count >1000/mm(3) at the start of the second course and an increase in the eosinophil count >100/mm(3) between the first and second infusions were correlated with an improved OS.

CONCLUSION

Ipilimumab toxic effect is manageable in real life. Biological data such as lymphocyte and eosinophil counts at the time of the second ipilimumab infusion appear to be early markers associated with better OS.

Survival after neuroAIDS: association with antiretroviral CNS Penetration-Effectiveness score

OBJECTIVE

We examined if the CNS Penetration-Effectiveness (CPE) score of antiretroviral drugs was associated with survival after a diagnosis of HIV-related encephalopathy, progressive multifocal leukoencephalopathy (PML), cerebral toxoplasmosis, or cryptococcal meningitis.

METHODS

Using data from the FHDH-ANRS CO4, we compared the survival of 9,932 HIV-infected patients diagnosed with a first neurologic AIDS-defining event in the pre-combination antiretroviral therapy (cART) (1992-1995), early cART (1996-1998), or late cART (1999-2004) periods. Follow-up was subdivided (CPE < 1.5 and CPE ≥ 1.5), and relative rates (RR) of death were estimated using multivariable Poisson regression models.

RESULTS

In the pre-cART and early cART periods, regimens with CPE ≥ 1.5 were associated with lower mortality after HIV-related encephalopathy (RR 0.64; 95% confidence interval [CI] 0.47-0.86 and RR 0.45; 95% CI 0.35-0.58) and after PML (RR 0.79; 95% CI 0.55-1.12 and RR 0.45; 95% CI 0.31-0.65), compared to regimens with CPE < 1.5, while in the late cART period there was no association between the CPE score and the mortality. A higher CPE score was also associated with a lower mortality in all periods after cerebral toxoplasmosis (RR 0.68, 95% CI 0.56-0.84) or cryptococcal meningitis (RR 0.50, 95% CI 0.34-0.74). Whatever the neurologic event, these associations were not maintained after adjustment on updated plasma HIV-RNA (missing, <500, ≥500 copies/mL) with RR ranging from 0.82 (95% CI 0.36-1.91) to 1.02 (0.69-1.52).

CONCLUSION

At the beginning of the cART era, the CPE score was of importance for survival after severe neurologic event, while in the late cART period, the additional effect of CPE score vanished with more powerful antiretroviral regimens associated with plasma viral load control.

Recovery of fat following a switch to nucleoside reverse transcriptase inhibitor-sparing therapy in patients with lipoatrophy: results from the 96-week randomized ANRS 108 NoNuke Trial

OBJECTIVES

To evaluate the impact on peripheral fat tissue of a nucleoside reverse transcriptase inhibitor (NRTI)-sparing regimen in lipoatrophic HIV-1 infected patients.

METHODS

This 96-week prospective, randomized study compared lipoatrophic patients switched to an NRTI-sparing regimen with patients remaining on an NRTI-containing regimen. The primary endpoint was the change in thigh subcutaneous fat tissue volume between baseline and week 48, as assessed by computerized tomography.

RESULTS

One hundred patients were included, 50 in each arm. At baseline, patients had been on highly active antiretroviral therapy (HAART) for a median time of 6.6 years (4.9-9.7); 71% of the patients had received thymidine analogues [stavudine (37%), zidovudine (34%)]. The mean change in fat volume between baseline and week 48 significantly favoured the NRTI-sparing arm over the NRTI-maintaining arm in the intent-to-treat analysis, with a last-observation-carried-forward approach [+34 cm(3); 95% confidence interval (CI) 5-63 cm(3); P=0.002]. This was confirmed in the intent-to-treat analysis of available data, with a mean difference of +109 cm(3) (95% CI 34-185 cm(3)) at week 96 (n=53; P=0.001). This corresponded to increases of 12 and 30% in fat volume at weeks 48 and 96, respectively, in the NRTI-sparing arm.

CONCLUSIONS

Switching from an effective NRTI-containing regimen to an NRTI-sparing regimen preserves immunovirological status and increases subcutaneous fat volume at weeks 48 and 96.

Impact of Newly Available Drugs on Clinical Progression in Patients with Virological Failure after Exposure to Three Classes of Antiretrovirals

Objective

To study the prognosis of HIV-infected patients with virological failure after exposure to three classes of antiretroviral drugs (ARVs).

Design

Cohort study. Setting: French Hospital Database on HIV.

Patients

Patients previously exposed to at least two nucleoside reverse transcriptase inhibitors (NRTIs), two protease inhibitors and one non-NRTI, with viral load (VL) values of >5000 copies/ml after the exposure criteria were met and a new treatment initiated between 1998 and 2001 with VL >5000 copies/ml.

Main outcome measures

Risk of new AIDS-defining-events (ADEs) or death from first introduction of a drug never used before occurring between 1998 and 2001 defined as baseline.

Results

The main baseline characteristics of the 1092 patients were: previous ADE in 49% of cases, median CD4 cell count 181 μl, median VL 4.9 log10 copies/ml, median duration of ARV therapy 5.0 years and previous exposure to a median of nine ARVs. The crude progression rates were 20.1/100 patient-years among patients included in 1998, 15.1 in 1999, 11.1 in 2000 and 8.6 in 2001. After adjustment for baseline characteristics, the calendar year of inclusion was associated with the risk of clinical progression ( P<0.001). When the types of newly available drugs used at baseline or during follow-up were introduced into the model, year of inclusion was no longer associated with the risk of clinical progression ( P=0.42), while exposure to amprenavir/r, lopinavir/r, abacavir or tenofovir was associated with a lower risk.

Conclusions

The clinical prognosis of heavily pretreated patients experiencing virological failure improved between 1998 and 2001, mainly thanks to the use of newly available drugs with more favourable resistance profiles.