Off-label drug use during the COVID-19 pandemic in Africa: topic modelling and sentiment analysis of ivermectin in South Africa and Nigeria as a case study

Although rejected by the World Health Organization, the human and even veterinary formulation of ivermectin has widely been used for prevention and treatment of COVID-19. In this work we leverage Twitter to understand the reasons for the drug use from ivermectin supporters, their source of information, their emotions, their gender demographics, and location information, in Nigeria and South Africa. Topic modelling is performed on a Twitter dataset gathered using keywords 'ivermectin' and 'ivm'. A model is fine-tuned on RoBERTa to find the stance of the tweets. Statistical analysis is performed to compare the stance and emotions. Most ivermectin supporters either redistribute conspiracy theories posted by influencers, or refer to flawed studies confirming ivermectin efficacy in vitro. Three emotions have the highest intensity, optimism, joy and disgust. The number of anti-ivermectin tweets has a significant positive correlation with vaccination rate. All the provinces in South Africa and most of the provinces of Nigeria are pro-ivermectin and have higher disgust polarity. This work makes the effort to understand public discussions regarding ivermectin during the COVID-19 pandemic to help policy-makers understand the rationale behind its popularity, and inform more targeted policies to discourage self-administration of ivermectin. Moreover, it is a lesson to future outbreaks.

Diagnostic utility and therapeutic impact of PET/CT [18F]F-Fluoromethylcholine -Choline in the biochemical recurrence of prostate cancer

OBJECTIVE

To assess the diagnostic capability of PET/CT with [¹⁸F]F-Fluoromethylcholine in prostate cancer (PC) with biochemical recurrence and its therapeutic impact.

MATERIAL AND METHODS

We included 108 patients, diagnosed with PC with biochemical criteria for recurrence. A PET/CT Choline scan was performed by dynamic pelvic and whole body study at 60min post-tracer injection. The relationship between the positive studies and the PSA value was analysed by classifying patients into three groups (<1.2/1.2-2/>2ng/ml), and the diagnostic capacity was assessed with respect to pelvic MRI and the impact on the therapeutic decision.

RESULTS

The location of recurrence was identified in 85 of 108 patients (78.7%): 34 local, 47 pelvic lymph nodes and 58 distant lesions, including retroperitoneal, mediastinal lymph nodes and distant organ lesions (bone and lung). Second tumors were diagnosed in 4 patients. No significant differences were found in the percentage of positive studies depending on primary treatment. Patients with PSA>2ng/ml showed a higher percentage of disease detection than patients with a lower PSA level, with significant differences (p<0.0001). PET/CT [¹⁸F]F-Choline was able to detect local disease, not previously known from MRI, in 29.41% of patients. PET/CT Choline had an impact on therapeutic management in 67 of 108 patients (62%).

CONCLUSIONS

PET/CT with [¹⁸F]F-Fluoromethylcholine is a useful tool in the detection of locoregional and disseminated disease of PC treated with suspicion of recurrence, providing a change in therapeutic management in 62% of patients.

Association between PD1 mRNA and response to anti-PD1 monotherapy across multiple cancer types

Background

We hypothesized that the abundance of PD1 mRNA in tumor samples might explain the differences in overall response rates (ORR) observed following anti-PD1 monotherapy across cancer types.

Patients and methods

RNASeqv2 data from 10 078 tumor samples representing 34 different cancer types was analyzed from TCGA. Eighteen immune-related gene signatures and 547 immune-related genes, including PD1, were explored. Correlations between each gene/signature and ORRs reported in the literature following anti-PD1 monotherapy were calculated. To translate the in silico findings to the clinical setting, we analyzed the expression of PD1 mRNA using the nCounter platform in 773 formalin-fixed paraffin embedded (FFPE) tumor samples across 17 cancer types. To test the direct relationship between PD1 mRNA, PDL1 immunohistochemistry (IHC), stromal tumor-infiltrating lymphocytes (sTILs) and ORR, we evaluated an independent FFPE-based dataset of 117 patients with advanced disease treated with anti-PD1 monotherapy.

Results

In pan-cancer TCGA, PD1 mRNA expression was found strongly correlated (r > 0.80) with CD8 T-cell genes and signatures and the proportion of PD1 mRNA-high tumors (80th percentile) within a given cancer type was variable (0%-84%). Strikingly, the PD1-high proportions across cancer types were found strongly correlated (r = 0.91) with the ORR following anti-PD1 monotherapy reported in the literature. Lower correlations were found with other immune-related genes/signatures, including PDL1. Using the same population-based cutoff (80th percentile), similar proportions of PD1-high disease in a given cancer type were identified in our in-house 773 tumor dataset as compared with TCGA. Finally, the pre-established PD1 mRNA FFPE-based cutoff was found significantly associated with anti-PD1 response in 117 patients with advanced disease (PD1-high 51.5%, PD1-intermediate 26.6% and PD1-low 15.0%; odds ratio between PD1-high and PD1-intermediate/low = 8.31; P < 0.001). In this same dataset, PDL1 tumor expression by IHC or percentage of sTILs was not found associated with response.

Conclusions

Our study provides a clinically applicable assay that links PD1 mRNA abundance, activated CD8 T-cells and anti-PD1 efficacy.

Fierce-21: Phase II study of vofatmab (B-701), a selective inhibitor of FGFR3, as salvage therapy in metastatic urothelial carcinoma (mUC)

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Background: Patients (pts) with mUC who have failed platinum-based chemotherapy have a poor prognosis. About 20% of them usually respond to immune checkpoint inhibitors (ICI). Also, 20% of pts with mUC harbor FGFR3 mutations or fusions (M/F), and this feature may be associated with lower sensitivity to ICI. Vofatamab (B-701) is a fully human monoclonal antibody against FGFR3 that blocks activation of the wildtype and genetically activated receptor. FIERCE-21 is a Phase 1b/2 study designed to evaluate vofatamab monotherapy (VM) or in combination with docetaxel (VD). Methods: The study consists of a P 1b lead-in (P1b with VD), previously reported followed by P2 expansion cohort in FGFR3 M/F+ pts (identified with the FoundationONE CDx™ assay on archival samples). The study enrolled mUC pts with failure to ≥ 1 line prior chemotherapy (including prior taxane treatment) or ≤12 months of (neo)adjuvant chemotherapy, measurable disease and ECOG ≤ 1. Treatment consisted of vofatamab at 25 mg/kg alone (VM) and in combination with D (VD) at 75 mg/m2 q3w. Efficacy was assessed by investigators (RECIST 1.1). Primary objectives were safety and activity (objective response-rate [ORR]). Results: 55 pts have received treatment. In the Ph 2 study, 21 pts received VM, 15 pts received VD. 35% of pts were included as 2nd line therapy, 65% in 3rd or later line of treatment. For pts receiving VD, safety was consistent with Ph 1B data. For pts receiving VM, median age was 67 yrs, ECOG 1 = 71.4%, Hgb < 10 gm/dL 13%, liver metastases 19%, ≥ 2 prior regimens 57%, (best response to prior therapy PD 31%). TEAEs occurring in ≥5% patients were asthenia (19%), diarrhea (9.5%), flushing 14%, chills (9.5%), hypotension (9.5%), decreased appetite (19%) and creatinine increased (9.5%). The majority of TEAS were grade 1 and 2. Only 1 patient on MF had a grade 3 TEAE and only 1 patient discontinued treatment due to an AE. The ORR have been seen in 7 pts to date including those receiving both VM and VD. Conclusions: Vofatamab both alone and combined with D in an every 3-week schedule are well tolerated with a low frequency of grade 3 TEAEs. Both VM and VD have demonstrated efficacy in terms of ORR, and mature results with PFS data will be presented. Clinical trial information: NCT02401542.

Acute tubulointerstitial nephritis associated with atezolizumab, an anti-programmed death-ligand 1 (pd-l1) antibody therapy

Direct stimulation of the antitumor activity of immune system through checkpoint inhibitors (ICIs) has demonstrated efficacy in the treatment of different cancer types. The activity of these antibodies takes place in the immunological synapse blocking the binding of the negative immunoregulatory proteins, thus leading to the finalization of the immune response. Despite having a favorable toxicity profile, its mechanism of action impedes the negative regulation of the immune activity which can potentially favor autoimmune attacks to normal tissues. Renal toxicity has been described in several ICI but not with atezolizumab, an IgG1 monoclonal antibody targeting PD-L1 (programmed death ligand 1), approved by FDA as a second-line therapy for advanced urothelial carcinoma. Here we present a patient with a single kidney and metastatic renal cell carcinoma treated with atezolizumab and bevacizumab combination, with biopsy-proven acute interstitial nephritis, who had a complete resolution of renal dysfunction after steroid therapy.

Androgen receptor gene status in plasma DNA associates with worse outcome on enzalutamide or abiraterone for castration-resistant prostate cancer: a multi-institution correlative biomarker study

BACKGROUND

There is an urgent need to identify biomarkers to guide personalized therapy in castration-resistant prostate cancer (CRPC). We aimed to clinically qualify androgen receptor (AR) gene status measurement in plasma DNA using multiplex droplet digital PCR (ddPCR) in pre- and post-chemotherapy CRPC.

METHODS

We optimized ddPCR assays for AR copy number and mutations and retrospectively analyzed plasma DNA from patients recruited to one of the three biomarker protocols with prospectively collected clinical data. We evaluated associations between plasma AR and overall survival (OS) and progression-free survival (PFS) in 73 chemotherapy-naïve and 98 post-docetaxel CRPC patients treated with enzalutamide or abiraterone (Primary cohort) and 94 chemotherapy-naïve patients treated with enzalutamide (Secondary cohort; PREMIERE trial).

RESULTS

In the primary cohort, AR gain was observed in 10 (14%) chemotherapy-naïve and 33 (34%) post-docetaxel patients and associated with worse OS [hazard ratio (HR), 3.98; 95% CI 1.74-9.10; P < 0.001 and HR 3.81; 95% CI 2.28-6.37; P < 0.001, respectively], PFS (HR 2.18; 95% CI 1.08-4.39; P = 0.03, and HR 1.95; 95% CI 1.23-3.11; P = 0.01, respectively) and rate of PSA decline ≥50% [odds ratio (OR), 4.7; 95% CI 1.17-19.17; P = 0.035 and OR, 5.0; 95% CI 1.70-14.91; P = 0.003, respectively]. AR mutations [2105T>A (p.L702H) and 2632A>G (p.T878A)] were observed in eight (11%) post-docetaxel but no chemotherapy-naïve abiraterone-treated patients and were also associated with worse OS (HR 3.26; 95% CI 1.47-not reached; P = 0.004). There was no interaction between AR and docetaxel status (P = 0.83 for OS, P = 0.99 for PFS). In the PREMIERE trial, 11 patients (12%) with AR gain had worse PSA-PFS (sPFS) (HR 4.33; 95% CI 1.94-9.68; P < 0.001), radiographic-PFS (rPFS) (HR 8.06; 95% CI 3.26-19.93; P < 0.001) and OS (HR 11.08; 95% CI 2.16-56.95; P = 0.004). Plasma AR was an independent predictor of outcome on multivariable analyses in both cohorts.

CONCLUSION

Plasma AR status assessment using ddPCR identifies CRPC with worse outcome to enzalutamide or abiraterone. Prospective evaluation of treatment decisions based on plasma AR is now required.

CLINICAL TRIAL NUMBER

NCT02288936 (PREMIERE trial).

Prognostic and predictive value of plasma testosterone levels in patients receiving first-line chemotherapy for metastatic castrate-resistant prostate cancer

BACKGROUND

Biomarkers for metastatic castration-resistant prostatic cancer (mCRPC) are an unmet medical need.

METHODS

The prognostic and predictive value for survival and response to salvage hormonal therapy (SHT) of baseline testosterone level (TL) was analysed in a cohort of 101 mCRPC patients participating in 9 non-hormonal first-line chemotherapy phase II-III trials. Inclusion criteria in all trials required a TL of <50 ng dl(-1).

RESULTS

Median age: 70 years; visceral metastases: 19.8%; median prostate-specific antigen (PSA): 50.7 ng ml(-1); median TL: 11.5 ng dl(-1). Median overall survival (OS; 24.5 months) was significantly longer if baseline TL was above (High TL; n=52) than under (Low TL; n=49) the TL median value (32.7 vs 22.4 months, respectively; P=0.0162, hazard ratio (HR)=0.6). The presence of anaemia was an unfavourable prognostic factor (median OS: 20.6 vs 28.4 months; P=0.0025, HR=1.88 (CI95%: 1.01-3.48)). Patients presenting both anaemia and low testosterone had a worse outcome compared to those with one or none of them (median OS: 17.9 vs 22.4 vs 38.1 months; P=0.0024). High vs Low TL was associated with PSA response rate (55.6% vs 21.7%) in 41 patients receiving SHT.

CONCLUSION

Testosterone level under castration range was a prognostic factor for survival mCRPC patients. The PSA response to SHT differed depending on TLs. Testosterone levels might help in treatment decision.

Phase II trial of sequential subcutaneous interleukin-2 plus interferon alpha followed by sorafenib in renal cell carcinoma (RCC)

PURPOSE

Immunotherapy (IL-2 and INF-α) was the treatment of choice for advanced renal cell carcinoma (RCC) until antiangiogenic therapy with tyrosin kinase inhibitors was developed in the early 2000s. This clinical trial explored the efficacy and toxicity of sequential treatment of IL-2 plus INF-α followed by sorafenib.

METHODS

Eligibility criteria included measurable, non-resectable, histologically confirmed predominantly clear cell RCC, no prior systemic treatment, and ECOG PS 0-2. The treatment regimen was a 6-week cycle of subcutaneous IL-2 at 9 × 10(6) IU on days 1-6 of weeks 1, 2, 4 and 5 plus s.c. INF-α at 6 × 10(6) IU on days 1, 3 and 5 of weeks 1-6. Responders received 6 additional weeks of this regimen. All patients received oral sorafenib (400 mg bid) after immunotherapy until disease progression. The primary endpoint was progression-free survival.

RESULTS

Forty-one patients were enrolled, median age 57 years. ECOG was 0/1 in 17/20 patients, 35 patients had prior nephrectomy and 18 patients pure clear cell cancer. Median PFS was 7.4 months (95 % CI 6.5-13.1) and OS was 16.6 months (95 % CI not reached). In 36 patients evaluable for response, ORR was 44.4 % and control rate was 94.4 %. Most adverse events (AEs) were Grade 1 or 2 toxicities (84.7 %). During immunotherapy the most common AEs were pyrexia (82.9 %), asthenia (56.1 %) and anorexia (46.3 %), whereas during sorafenib were diarrhoea (48.8 %) and hand-foot syndrome (46.3 %).

CONCLUSIONS

A sequential regimen of IL-2 and INF-α followed by sorafenib showed effectiveness and manageable toxicity in patients with advanced RCC.