Phase II Study of Panitumumab Monotherapy in Chemotherapy‐Naïve Frail or Elderly Patients with Unresectable RAS Wild‐Type Colorectal Cancer: OGSG 1602

Lessons Learned

• Panitumumab monotherapy showed favorable efficacy and feasibility in the treatment of frail or elderly patients with RAS wild‐type unresectable colorectal cancer.
• It is especially effective for left‐sided tumors; therefore, panitumumab as first‐line treatment could be an additional therapeutic option for frail elderly patients, particularly in those who are unsuitable for upfront oxaliplatin‐based or irinotecan‐based combination regimens.

BackgroundFirst‐line panitumumab monotherapy is expected to be well tolerated and improve survival in patients ineligible for intensive chemotherapy. However, its safety and efficacy in chemotherapy‐naïve frail or elderly patients with unresectable RAS wild‐type (WT) colorectal cancer (CRC) have not been studied. The aim of this phase II trial was to evaluate the efficacy and safety of panitumumab as first‐line treatment.MethodsWe conducted a multicenter phase II study on patients aged ≥76 years or ≥65 years considered unsuitable for intensive chemotherapy. Panitumumab 6 mg/kg of intravenous infusion was administered every 2 weeks. The primary endpoint was disease control rate (DCR). Secondary endpoints included progression‐free survival (PFS), overall survival (OS), response rate (RR), time to treatment failure (TTF), and incidence of grade 3 or 4 toxicities.ResultsThirty‐six patients (median age: 81 [range, 67–88] years) were enrolled between February 2017 and August 2018. Two patients were excluded from the analysis of efficacy: one from lack of image examination at baseline and the other from lack of a measurable lesion. Thirty‐three (91.6%) patients had a performance status (PS) of 0 or 1, whereas two (5.6%) patients and one (2.8%) patient had a PS of 2 and 3, respectively. Twenty‐eight patients (77.8%) had left‐sided CRC, whereas eight (22.2%) had right‐sided CRC. The RR was 50.0% (95% confidence interval [CI], 32.4–67.6), including three patients (8.8%) who had complete responses. A total of 26.5% had stable diseases, resulting in a DCR of 76.5% (90% CI, 61.5–87.7). The RR of patients with left‐ and right‐sided tumors was 65.4% (95% CI, 44.3–82.8) and 0.0% (95% CI, 0.0–36.9), respectively. Major grade 3 or 4 nonhematologic toxicities were rash (n = 6, 16.7%), hypomagnesemia (n = 4, 11.1%), fatigue (n = 3, 8.3%), paronychia (n = 2, 5.6%), and hyponatremia (n = 2, 5.6%). The only grade 3 hematologic toxicity was neutropenia (n = 1, 2.8%).ConclusionPanitumumab monotherapy showed favorable efficacy and feasibility in frail or elderly patients with RAS WT unresectable CRC. Survival analysis including OS, PFS, and TTF is currently in progress.     

Successful use of the two-tube approach for the treatment of phenobarbital poisoning without hemodialysis

Half-life of the antipsychotic vegetamin is very long, partially due to the presence of phenobarbital, and mortality due to phenobarbital poisoning is high. Here, we present the case of a 22-year-old female admitted to the emergency department with disturbed consciousness due to vegetamin overdose. Her blood phenobarbital level was elevated to 123 μg/ml. Phenobarbital undergoes enterohepatic circulation, and its retention in the intestine causes its blood levels to remain sustained. The utility of hemodialysis for drug poisoning has been previously reported; however, its efficiency is not yet established and its efficacy is low for drugs with long half-lives such as phenobarbital. Therefore, we performed a two-tube approach to adsorb phenobarbital in the intestines with activated charcoal delivered via a gastric tube and to remove the phenobarbital-adsorbed activated charcoal using whole bowel irrigation via an ileus tube 2 h later. The patient successfully eliminated the charcoal via stool, the blood phenobarbital level decreased drastically without hemodialysis, and the clinical course improved. We propose that this two-tube approach is suitable for treatment of poisoning with drugs that undergo enterohepatic circulation and have long half-lives.     

Survey of Japanese dermatological vasculitis specialists on cases of cutaneous arteritis (cutaneous polyarteritis nodosa)

We developed a questionnaire to examine the findings of cutaneous arteritis among dermatological specialists experienced in vasculitis as certified by the Committee for guidelines for the management of vasculitis and vascular disorders of the Japanese Dermatological Association. We sent a questionnaire to 12 dermatological facilities identified through the revised Committee for guidelines for the management of vasculitis and vascular disorders of the Japanese Dermatological Association. Retrospective data obtained from 84 patients at the 12 dermatological facilities between 2012 January 2016 December were evaluated. The 84 patients were categorized into two groups, a systemic steroid treatment group (group 1, n = 52) and a no systemic steroid treatment group (group 2, n = 32). C-reactive protein in group 1 patients was significantly higher than that in group 2 patients. Frequency of fever, arthritis, myalgia- and peripheral neuropathy in group 1 was significantly higher than that in group 2. We propose that these symptoms could serve as early markers for the transfer from cutaneous arteritis to systemic polyarteritis nodosa. We further suggest that patients who are subsequently associated with cerebral hemorrhage and infarction, who are originally diagnosed as having cutaneous arteritis, could progress to systemic polyarteritis nodosa. The study demonstrated that it is important for dermatologists to detect these findings early in order to establish an accurate diagnosis and a timely treatment.