A Retrospective, Observational Study of 12 Cases of Expanded-Access Customized Phage Therapy: Production, Characteristics, and Clinical Outcomes

BACKGROUND

Antimicrobial resistance (AMR) is undermining modern medicine, a problem compounded by bacterial adaptation to antibiotic pressures. Phages are viruses that infect bacteria. Their diversity and evolvability offer the prospect of their use as a therapeutic solution. Reported are outcomes of customized phage therapy for patients with difficult-to-treat antimicrobial resistant infections.

METHODS

We retrospectively assessed 12 cases of customized phage therapy from a phage production center. Phages were screened, purified, sequenced, characterized, and Food and Drug Administration-approved via the IND (investigational new drug) compassionate-care route. Outcomes were assessed as favorable or unfavorable by microbiologic and clinical standards. Infections were device-related or systemic. Other experiences such as time to treatment, antibiotic synergy, and immune responses were recorded.

RESULTS

Fifty requests for phage therapy were received. Customized phages were generated for 12 patients. After treatment, 42% (5/12) of cases showed bacterial eradication and 58% (7/12) showed clinical improvement, with two-thirds of all cases (66%) showing favorable responses. No major adverse reactions were observed. Antibiotic-phage synergy in vitro was observed in most cases. Immunological neutralization of phages was reported in 5 cases. Several cases were complicated by secondary infections. Complete characterization of the phages (morphology, genomics, and activity) and their production (methods, sterility, and endotoxin tests) are reported.

CONCLUSIONS

Customized phage production and therapy was safe and yielded favorable clinical or microbiological outcomes in two-thirds of cases. A center or pipeline dedicated to tailoring the phages against a patient's specific AMR bacterial infection may be a viable option where standard treatment has failed.

2670. Clostridioides difficile Infection (CDI) in Solid-Organ (SOT) and Hematopoietic Stem Cell Transplant (HCT) Recipients: A Prospective Multinational Study

Background

CDI is an important cause of morbidity and mortality in SOT and HCT patients (pts). In retrospective single-center analyses, severe disease and relapse were common. We undertook a multicenter prospective observational study to evaluate outcomes of CDI among both SOT and HCT patients.

Methods

Adults with a first episode of CDI, defined as 3 liquid stools/24 h with the detection of C. difficile toxin in stool, within the first 2 years of SOT or HCT were recruited from 12 centers internationally in the INSIGHT network. At enrollment, demographics, comorbidities, medication histories and outcomes were collected prospectively over 90 days to assess clinical cure, recurrences and complications and to define baseline risk factors for clinical cure and recurrent CDI.

Results

132 patients (81 SOT, 51 HCT (32 allogeneic)) were enrolled: median age 56 years, 62.1% were males, 97% were hospitalized. 80.3% were diagnosed by DNA assay. CDI occurred a median of 20 days post transplant (IQR: 6–133). 108 patients were on PPIs. 98.5% were on antibiotics before CDI. 1^st line treatment regimen was oral vancomycin in 66 patients (40 SOT, 26 HCT), metronidazole in 48 patients (27 SOT, 21 HCT), both drugs in 14 (10 SOT, 4 HCT), fidaxomicin (3) and linezolid (1). Rejection within 60 days before CDI was uncommon (6.2% SOT) as was GVHD (27.5%). 110 patients (83%, 95% CI: 46–89)) (65 SOT, 45 HCT) had clinical cure; 18% (95% CI: 11–27) had recurrent CDI, 2 were admitted to the ICU due to CDI, 11 (8.3%) died (2 HCT related to CDI). Among baselines variables, only first-line regimen was associated with a higher rate of clinical cure (P = 0.003), most notably for SOT. Factors that did not have a statistically significant negative impact on clinical cure included sex, age > 60, race, country, transplant type, steroids, diabetes, CMV viremia/disease, WBC > 15,000, creatinine > 1.5 mg/dL, or specific antibiotic given prior to CDI. Higher recurrence rates were associated with metronidazole-only regimen (OR: 4.6, 95% CI: 1.6–12.8; P = 0.004) and a history of CMV after transplant (OR: 5.2, 95% CI: 1.7–15.7; P = 0.003).

Conclusion

Despite their immunosuppressed state, recurrence, ICU admission and mortality occurred in a minority of SOT and HCT with CDI. Initial use of metronidazole and CMV viremia/disease were associated with higher recurrence rates.

Disclosures

All authors: No reported disclosures.

Multiple transmissions of chromosomally integrated human herpesvirus-6 in one family

Chromosomally integrated human herpesvirus-6 (ciHHV-6) can be transmitted from parent to child or via allogeneic hematopoietic cell transplantation (HCT). We report a case of ciHHV-6 transmitted via syngeneic HCT, and vertically across 3 generations. ciHHV-6 was transmitted from a parent to the patient and her identical twin, and from the patient to her son. The patient underwent syngeneic HCT as rescue from chemotherapy-induced aplasia during which ciHHV-6 was re-transmitted to her, this time from her identical twin. This is the first report, to our knowledge, of a patient acquiring ciHHV-6 once via germline from a parent and again via syngeneic HCT from an identical twin.

Recombinant tissue plasminogen activator to declot dialysis fistulas

BACKGROUND

Thrombosis is the most common complication of hemodialysis access. Few reports are available concerning the use of recombinant tissue plasminogen activator (rt-PA) to declot an arterio-venous (A-V) access. This report describes the use of rt-PA for this purpose in 17 A-V accesses.

METHODS

The rt-PV was infused manually using a small catheter directly into the A-V access in 10-mg doses at 1-2 hour intervals, to a maximum dose of 40 mg. The procedure was followed by angiography, through the same catheter.

RESULTS

One fistula could not be cannulated, and in three the lysis of the clot failed. The other 13 cases (3 fistulas, and 10 grafts 81%) had successful lysis with return of bruit and thrill. Most patients had dialysis the next day using the declotted A-V access. Angiogram detected stenosis in six patients and surgical revision was done 1-8 days after the treatment. In the other seven patients no organic lesions were found, and six of them have a functioning A-V access 50-395 days after the lysis. Only 10-20 mg of rt-Pa was needed in 60% of the cases. No major complication occurred; minor local bleeding was noted in five patients (5/16, 31%).

CONCLUSION

rt-PA can be considered safe, effective, and fast for declotting thrombosed arteriovenous fistulas.

Severe lactic acidosis and renal involvement in a patient with relapsed Burkitt's lymphoma

We describe an 8-year-old patient with relapsed Burkitt's lymphoma who developed complex metabolic problems, including renal diabetes insipidus and severe lactic acidosis. The lactic acidosis responded temporarily to chemo- and radiotherapy but not to bicarbonate or thiamine administration. These metabolic changes were most likely due to the lymphomatous infiltration of the kidneys. Severe lactic acidosis, without evidence of thiamine deficiency, seems to be a very rare event in children with cancer.