Use of Anti-Glycopeptidolipid-Core Antibodies Serology for Diagnosis and Monitoring of Mycobacterium avium Complex Pulmonary Disease in the United States

Background

There is an unmet need for rapid, accurate, and noninvasive assays for diagnosis and monitoring of Mycobacterium avium complex pulmonary disease (MAC-PD). We evaluated the diagnostic accuracy of an anti-glycopeptidolipid (GPL)-core immunoglobulin A (IgA) antibody test in a US cohort of MAC patients, and we described serial serology changes during antimicrobial therapy.

Methods

We identified serum samples from MAC patients starting treatment at enrollment and control subjects with or without bronchiectasis within OHSU's NTM Biobank. We conducted diagnostic test accuracy. Changes in mean levels of anti-GPL-core IgA antibodies between 0 and 3, 6, or 12 months after treatment start were assessed using the Student's paired t test. Pearson's correlation coefficient was calculated for IgA antibody levels and Student paired t test measures.

Results

We included 25 MAC patients and 18 controls. At baseline, IgA antibody concentrations in MAC patients (3.40 ± 6.77 U/mL) were significantly higher than in controls without bronchiectasis (0.14 ± 0.03 U/mL, P = .02). Sensitivity and specificity for MAC-PD in this population was 48% and 89% (cutoff point 0.7 U/mL), respectively. Among MAC patients starting antimicrobial therapy, mean IgA levels decreased 0.3202 U/mL (P = .86) at month 3, 0.8678 U/mL (P = .47) at month 6, and 1.9816 U/mL (P = .41) at 1 year. Quality of Life-Bronchiectasis Respiratory Symptom Scale improvement correlated with decreasing IgA titers after 12 months of treatment in MAC patients (r = −0.50, P = .06).

Conclusions

Anti-GPL-core IgA antibody levels are relatively specific for MAC-PD and decrease with treatment. Larger studies are warranted to evaluate the role of IgA serology in monitoring treatment response or for disease relapse/reinfection.

ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Soluble immune effector molecules [II]: agents targeting interleukins, immunoglobulins and complement factors)

BACKGROUND

The present review is part of the ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies.

AIMS

To review, from an Infectious Diseases perspective, the safety profile of agents targeting interleukins, immunoglobulins and complement factors and to suggest preventive recommendations.

SOURCES

Computer-based MEDLINE searches with MeSH terms pertaining to each agent or therapeutic family.

CONTENT

Patients receiving interleukin-1 (IL-1) -targeted (anakinra, canakinumab or rilonacept) or IL-5-targeted (mepolizumab) agents have a moderate risk of infection and no specific prevention strategies are recommended. The use of IL-6/IL-6 receptor-targeted agents (tocilizumab and siltuximab) is associated with a risk increase similar to that observed with anti-tumour necrosis factor-α agents. IL-12/23-targeted agents (ustekinumab) do not seem to pose a meaningful risk of infection, although screening for latent tuberculosis infection may be considered and antiviral prophylaxis should be given to hepatitis B surface antigen-positive patients. Therapy with IL-17-targeted agents (secukinumab, brodalumab and ixekizumab) may result in the development of mild-to-moderate mucocutaneous candidiasis. Pre-treatment screening for Strongyloides stercoralis and other geohelminths should be considered in patients who come from areas where these are endemic who are receiving IgE-targeted agents (omalizumab). C5-targeted agents (eculizumab) are associated with a markedly increased risk of infection due to encapsulated bacteria, particularly Neisseria spp. Meningococcal vaccination and chemoprophylaxis must be administered 2-4 weeks before initiating eculizumab. Patients with high-risk behaviours and their partners should also be screened for gonococcal infection.

IMPLICATIONS

Preventive strategies are particularly encouraged to minimize the occurrence of neisserial infection associated with eculizumab.

Infections from seven clinical trials of ixekizumab, an anti-interleukin-17A monoclonal antibody, in patients with moderate-to-severe psoriasis

BACKGROUND

Infections are associated with biological therapies in psoriasis.

OBJECTIVES

To summarize the incidence of infections in patients with moderate-to-severe psoriasis treated with ixekizumab, an anti-interleukin-17A monoclonal antibody.

METHODS

Infections are summarized from an integrated database of seven controlled and uncontrolled ixekizumab psoriasis trials. Data are presented from placebo-controlled induction (weeks 0-12; UNCOVER-1, UNCOVER-2 and UNCOVER-3) and maintenance periods (weeks 12-60; UNCOVER-1 and UNCOVER-2), and all patients exposed to ixekizumab pooled from all seven trials. Comparisons with etanercept were made during the induction period of two trials (UNCOVER-2 and UNCOVER-3). Incidence and exposure-adjusted incidence rates (IRs) per 100 patient-years (PYs) are reported.

RESULTS

Overall, 4209 patients were treated with ixekizumab (6480 PY). During induction (weeks 0-12), overall infection rates were higher in patients treated with ixekizumab (27%) vs. placebo (23%, P < 0·05); however, specific infection rates were comparable overall across treatment groups. IRs of infections did not increase with longer-term exposure. For all patients treated with ixekizumab (all seven trials), the incidence of serious infections was low (2%, IR 1·3). Candida infections, including eight cases of oesophageal candidiasis, were adequately managed with antifungal therapy, were noninvasive and did not lead to discontinuation.

CONCLUSIONS

Overall, infections occurred in a higher percentage of patients treated with ixekizumab vs. placebo during the first 12 weeks of treatment; however, specific infection rates were comparable overall across treatment groups. Incidences of serious infections were low and similar across treatment groups.

Tuberculosis and other opportunistic infections in tofacitinib-treated patients with rheumatoid arthritis

OBJECTIVES

To evaluate the risk of opportunistic infections (OIs) in patients with rheumatoid arthritis (RA) treated with tofacitinib.

METHODS

Phase II, III and long-term extension clinical trial data (April 2013 data-cut) from the tofacitinib RA programme were reviewed. OIs defined a priori included mycobacterial and fungal infections, multidermatomal herpes zoster and other viral infections associated with immunosuppression. For OIs, we calculated crude incidence rates (IRs; per 100 patient-years (95% CI)); for tuberculosis (TB) specifically, we calculated rates stratified by patient enrolment region according to background TB IR (per 100 patient-years): low (≤0.01), medium (>0.01 to ≤0.05) and high (>0.05).

RESULTS

We identified 60 OIs among 5671 subjects; all occurred among tofacitinib-treated patients. TB (crude IR 0.21, 95% CI of (0.14 to 0.30)) was the most common OI (n=26); median time between drug start and diagnosis was 64 weeks (range 15-161 weeks). Twenty-one cases (81%) occurred in countries with high background TB IR, and the rate varied with regional background TB IR: low 0.02 (0.003 to 0.15), medium 0.08 (0.03 to 0.21) and high 0.75 (0.49 to 1.15). In Phase III studies, 263 patients diagnosed with latent TB infection were treated with isoniazid and tofacitinib concurrently; none developed TB. For OIs other than TB, 34 events were reported (crude IR 0.25 (95% CI 0.18 to 0.36)).

CONCLUSIONS

Within the global tofacitinib RA development programme, TB was the most common OI reported but was rare in regions of low and medium TB incidence. Patients who screen positive for latent TB can be treated with isoniazid during tofacitinib therapy.

Opportunistic infections and biologic therapies in immune-mediated inflammatory diseases: consensus recommendations for infection reporting during clinical trials and postmarketing surveillance

No consensus has previously been formed regarding the types and presentations of infectious pathogens to be considered as ‘opportunistic infections’ (OIs) within the setting of biologic therapy. We systematically reviewed published literature reporting OIs in the setting of biologic therapy for inflammatory diseases. The review sought to describe the OI definitions used within these studies and the types of OIs reported. These findings informed a consensus committee (infectious diseases and rheumatology specialists) in deliberations regarding the development of a candidate list of infections that should be considered as OIs in the setting of biologic therapy. We reviewed 368 clinical trials (randomised controlled/long-term extension), 195 observational studies and numerous case reports/series. Only 11 observational studies defined OIs within their methods; no consistent OI definition was identified across studies. Across all study formats, the most numerous OIs reported were granulomatous infections. The consensus group developed a working definition for OIs as ‘indicator’ infections, defined as specific pathogens or presentations of pathogens that ‘indicate’ the likelihood of an alteration in host immunity in the setting of biologic therapy. Using this framework, consensus was reached upon a list of OIs and case-definitions for their reporting during clinical trials and other studies. Prior studies of OIs in the setting of biologic therapy have used inconsistent definitions. The consensus committee reached agreement upon an OI definition, developed case definitions for reporting of each pathogen, and recommended these be used in future studies to facilitate comparison of infection risk between biologic therapies.

Incidence and risk factors for progressive multifocal leukoencephalopathy among patients with selected rheumatic diseases

OBJECTIVE

To ascertain the incidence of progressive multifocal leukoencephalopathy (PML) in patients with selected rheumatic diseases, to describe the characteristics of PML cases occurring in this setting, and to evaluate the extent to which such cases occurred in the context of biologic therapies such as rituximab or tumor necrosis factor antagonists.

METHODS

We conducted a large population-based study to describe the incidence and risk factors for PML among patients with rheumatoid arthritis, psoriatic arthritis, psoriasis, juvenile idiopathic arthritis, inflammatory bowel disease, and ankylosing spondylitis using national inpatient and outpatient administrative data from the entire Center for Medicare and Medicaid Services from 2000-2009. Suspected PML cases were identified using hospital discharge diagnosis codes. Risk factors for PML were evaluated using outpatient data ≥6 months prior to PML diagnosis.

RESULTS

Among 2,030,578 patients with autoimmune diseases of interest, a total of 53 PML cases were identified (2.6 per 100,000 patients). Most PML cases had human immunodeficiency virus (HIV) and/or cancer. Nine PML cases had evidence for biologic use prior to PML hospitalization, of which 3 had neither HIV nor malignancy and were exposed to biologics within 12 (rituximab) or 6 months (all other biologics) prior to PML diagnosis. PML occurred at an estimated incidence of 0.2 per 100,000 patients with autoimmune diseases who did not have HIV or malignancy.

CONCLUSION

PML occurs at a very low incidence among patients with rheumatic diseases but can occur even in the absence of HIV or malignancy.

Mycobacterial diseases and antitumour necrosis factor therapy in USA

OBJECTIVE

In North America, tuberculosis and nontuberculous mycobacterial (NTM) disease rates associated with antitumour necrosis factor α (anti-TNFα) therapy are unknown.

METHODS

At Kaiser Permanente Northern California, the authors searched automated pharmacy records to identify inflammatory disease patients who received anti-TNF therapy during 2000-2008 and used validated electronic search algorithms to identify NTM and tuberculosis cases occurring during anti-TNF drug exposure.

RESULTS

Of 8418 anti-TNF users identified, 60% had rheumatoid arthritis (RA). Among anti-TNF users, 18 developed NTM and 16 tuberculosis after drug start. Anti-TNF associated rates of NTM and tuberculosis were 74 (95% CI: 37 to 111) and 49 (95% CI: 18 to 79) per 100 000 person-years, respectively. Rates (per 100, 000 person-years) for NTM and tuberculosis respectively for etanercept were 35 (95% CI: 1 to 69) and 17 (95% CI: 0 to 41); infliximab, 116 (95% CI: 30 to 203) and 83 (95% CI: 10 to 156); and adalimumab, 122 (95% CI: 3 to 241) and 91 (95% CI: 19 to 267). Background rates for NTM and tuberculosis in unexposed RA-patients were 19.2 (14.2 to 25.0) and 8.7 (5.3 to 13.2), and in the general population were 4.1 (95% CI 3.9 to 4.4) and 2.8 (95% CI 2.6 to 3.0) per 100, 000 person-years. Among anti-TNF users, compared with uninfected individuals, NTM case-patients were older (median age 68 vs 50 years, p<0.01) and more likely to have RA (100% vs 60%, p<0.01); whereas, tuberculosis case-patients were more likely to have diabetes (37% vs 16%, p=0.02) or chronic renal disease (25% vs 6%, p=0.02).

CONCLUSIONS

Among anti-TNF users in USA, mycobacterial disease rates are elevated, and NTM is associated with RA.

High level disinfection of a home care device; to boil or not to boil?

We developed a percutaneous electrical transducer for home therapy of chronic pain, a device that requires high level disinfection between uses. The utility of boiling water to provide high level disinfection was evaluated by inoculating transducer pads with potential skin pathogens (Staphylococcus aureus, Mycobacterium terrae, Pseudomonas aeruginosa, Candida albicans) and subjecting them to full immersion in water boiling at 4200 feet elevation (95 °C). Log10 reductions in colony-forming units (cfu) at 10 min were 7.1, >6.3 and >5.5 for S. aureus, P. aeruginosa and C. albicans, respectively, but only 4.6 for M. terrae. At 15 min the reductions had increased to 7.5, >6.8, >6.6 and >7.5 cfu, respectively.

European League Against Rheumatism recommendations for the management of psoriatic arthritis with pharmacological therapies

BACKGROUND

Psoriatic arthritis (PsA) is a clinically heterogeneous disease. Clear consensual treatment guidance focused on the musculoskeletal manifestations of PsA would be advantageous. The authors present European League Against Rheumatism (EULAR) recommendations for the treatment of PsA with systemic or local (non-topical) symptomatic and disease-modifying antirheumatic drugs (DMARD).

METHODS

The recommendations are based on evidence from systematic literature reviews performed for non-steroidal anti-inflammatory drugs (NSAID), glucocorticoids, synthetic DMARD and biological DMARD. This evidence was discussed, summarised and recommendations were formulated by a task force comprising 35 representatives, and providing levels of evidence, strength of recommendations and levels of agreement.

RESULTS

Ten recommendations were developed for treatment from NSAID through synthetic DMARD to biological agents, accounting for articular and extra-articular manifestations of PsA. Five overarching principles and a research agenda were defined.

CONCLUSION

These recommendations are intended to provide rheumatologists, patients and other stakeholders with a consensus on the pharmacological treatment of PsA and strategies to reach optimal outcomes, based on combining evidence and expert opinion. The research agenda informs directions within EULAR and other communities interested in PsA.

Current evidence for the management of rheumatoid arthritis with biological disease-modifying antirheumatic drugs: a systematic literature review informing the EULAR recommendations for the management of RA

OBJECTIVES

To review the evidence for the efficacy and safety of biological agents in patients with rheumatoid arthritis (RA) to provide data to develop treatment recommendations by the European League Against Rheumatism (EULAR) Task Force.

METHODS

Medline, Embase and Cochrane databases were searched for relevant articles on infliximab (IFX), etanercept (ETN), adalimumab (ADA), certolizumab-pegol (CZP), golimumab (GLM), anakinra (ANA), abatacept (ABT), rituximab (RTX) and tocilizumab (TCZ) published between 1962 and February 2009; published abstracts from the 2007-2008 American College of Rheumatology (ACR) and EULAR conference were obtained.

RESULTS

87 articles and 40 abstracts were identified. In methotrexate (MTX) naïve patients, biological therapy with IFX, ETN, ADA, GLM or ABT has been shown to improve clinical outcomes (level of evidence 1B). In MTX/other synthetic disease-modifying antirheumatic drug (DMARD) failures all nine biological agents confer benefit (1B), with lower efficacy noted for ANA. RTX, ABT, TCZ and GLM demonstrate efficacy in tumour necrosis factor inhibitor (TNFi) failures (1B). Less evidence exists for switching between IFX, ETN and ADA (3B). Biological and MTX combination therapy is more efficacious than a biological agent alone (1B). A safety review shows no increased malignancy risk compared with conventional DMARDs (3B). TNFi are generally associated with an increased risk of serious bacterial infection, particularly within the first 6 months of treatment initiation; increased tuberculosis (TB) rates with TNFi are highest with the monoclonal antibodies (3B).

CONCLUSIONS

There is good evidence for the efficacy of biological agents in patients with RA. Safety data confirm an increased risk of bacterial infection and TB with TNFi compared with conventional DMARDs.

Isolation of non-tuberculous mycobacteria from the sputum of patients with active tuberculosis

We looked for non-tuberculous mycobacteria (NTM) in the sputum of patients diagnosed with pulmonary tuberculosis (TB) in Oregon in 2005-2006 (n = 141). Twenty (14%) patients had NTM isolated from sputum during TB treatment. Compared to those without NTM, TB patients with NTM were more likely to have cavitary disease (RR 2.7, 95%CI 1.2-6.0) and were more likely to be born in the United States (RR 2.4, 95%CI 1.1-5.3). Further study is needed to determine the clinical significance of simultaneous isolation of NTM and TB.

Treatment patterns of pediatric nontuberculous mycobacterial (NTM) cervical lymphadenitis as reported by nationwide surveys of pediatric otolaryngology and infectious disease societies

OBJECTIVE

To describe physician diagnostic and therapeutic strategies for pediatric nontuberculous mycobacterial (NTM) lymphadenitis, a disease for which surgical excision is recommended.

METHODS

We surveyed members of the Infectious Diseases Society of America Emerging Infections Network (EIN) and the American Society of Pediatric Otolaryngology (ASPO). We asked them to report clinical and microbiologic details of recent cases of NTM lymphadenitis seen in their practices.

RESULTS

200 physicians reported a total of 277 NTM lymphadenitis cases. Cervical lymph nodes (84%) were most frequently involved, and a majority of patients were non-Hispanic white (62%) males (54%) with median age 3.0 years. Tissue culture (61%) or polymerase chain reaction (12%) was utilized most frequently to confirm NTM etiology. In most (59%) cases, an etiologic organism was not identified. In cases, where an NTM organism isolate was identified, Mycobacterium avium complex (n=82, 72%) was the most common. Surgical excision followed by adjunctive antibiotic therapy was favored in the majority (59%) of cases where a treatment method was reported. The use of surgical excision alone or antibiotic therapy alone was reported respectively in 24% and 17% of cases. Antibiotics were prescribed without diagnostic confirmation of infectious organisms in 28% of cases.

CONCLUSION

Pediatric otolaryngologists and infectious disease specialists frequently treat cervical lymphadenitis empirically as NTM disease without bacteriologic confirmation. Antibiotic therapy is frequently employed with or without surgical excision.

Serious infections with antirheumatic therapy: are biologicals worse?

This paper reviews the current evidence for the role of antirheumatic therapy in the development of serious infections in patients with rheumatoid arthritis (RA). Prednisone is clearly associated with increased infectious risk, but no definitive data link methotrexate to infection. Emerging data suggest that biological agents also pose increase infectious risk, particularly when used in combination with corticosteroids or methotrexate. Further research is needed in this important aspect of RA treatment. In the meantime, the author recommends that physicians should remain vigilant for serious infections in their patients with RA and use appropriate vaccines and screening procedures to mitigate their risk.

Investigation of human contacts: a Mycobacterium bovis outbreak among cattle at a California dairy

BACKGROUND

In May 2002, a Mycobacterium bovis outbreak occurred among cattle at a California dairy. We investigated to determine whether persons were infected after working with the cattle or drinking their raw milk.

METHODS

We identified persons with potential contact with infected cattle, including dairy workers, their family members, and slaughterhouse workers. Persons were given a tuberculin skin test (TST), and their occupational and milk-drinking habits were recorded.

RESULTS

Of 88 potential contacts, 78 (90%) were given a TST; 33 (43%) had positive TST results, of whom 32 were Mexican-born (RR 15.8, 95%CI 2.3-108.8). No persons had active tuberculosis. Eighteen (72%) dairy workers, 11 (27%) family members, and four (33%) slaughterhouse workers had positive TST results. After adjusting for Mexican-birth and age, dairy workers were no more likely to have positive TST results than others (adjusted RR 1.2, 95%CI 0.6-2.1). Forty-one (62%) dairy staff and their family members drank raw milk from the dairy; 21 (51%) had positive TST results and were Mexican-born. All 13 US-born raw milk drinkers had negative TST results.

CONCLUSION

A high prevalence of positive TST results was documented among workers at the affected dairy, although results were not independently associated with contact with infected cattle or milk products. Further assessment of California dairy workers should be considered.

Alfalfa sprouts and Salmonella Kottbus infection: a multistate outbreak following inadequate seed disinfection with heat and chlorine

Raw sprouts have been implicated in a number of foodborne disease outbreaks. Because contaminated seeds are usually responsible, many sprout producers attempt to disinfect seeds before germination and detect sprout contamination during production. In March 2001, we detected an increased number of Salmonella serotype Kottbus isolates in California. Overall, we identified 31 cases from three western states. To identify the cause, we conducted a case-control study with the first 10 identified case-patients matched to 20 controls by age, sex, and residential area. Our case-control study found illness to be statistically associated with alfalfa sprout consumption. The traceback investigation implicated a single sprouter, where environmental studies yielded Salmonella Kottbus from ungerminated seeds and floor drains within the production facility. Pulsed-field gel electrophoresis patterns of all patient, seed, and floor drain Salmonella Kottbus isolates were indistinguishable. Most implicated sprouts were from seeds that underwent heat treatment and soaking with a 2,000-ppm sodium hypochlorite solution rather than the Food and Drug Administration (FDA)-recommended 20,000-ppm calcium hypochlorite soak. Other implicated seeds had been soaked in a calcium hypochlorite solution that, when tested, measured only 11,000 ppm. The outbreak might have been averted when screening tests of sprout irrigation water detected Salmonella in January; however, confirmatory testing of these samples was negative (but testing improperly utilized refrigerated irrigation water). Producers should use the enrichment broth of positive screening samples, not refrigerated irrigation water, for confirmatory testing. Until other effective disinfection technologies are developed, producers should adhere to FDA recommendations for sprout seed disinfection.

Cluster of Mycobacterium chelonae keratitis cases following laser in-situ keratomileusis

PURPOSE

To describe a cluster of Mycobacterium chelonae keratitis cases involving patients who underwent laser in-situ keratomileusis (LASIK) at a single refractive surgery center.

DESIGN

Descriptive case series of four patients and cohort study to identify disease associations.

METHODS

Examination schedules, diagnostic tests, and therapy were based on best medical judgment. Isolates from three patients were compared by pulsed-field gel electrophoresis. Epidemiologic studies were performed to identify the source of infection.

RESULTS

Seven of eight eyes developed M. chelonae keratitis following bilateral simultaneous LASIK. Each patient was thought to have diffuse lamellar keratitis initially, but all seven eyes were noted to have opacities suggestive of infectious keratitis by 13 to 21 days after surgery. All eyes had undergone hyperopic LASIK over four days in April 2001 by one surgeon in a community-based refractive surgery center. A cohort study of all patients undergoing LASIK at the same center in April 2001 revealed that M. chelonae keratitis occurred only in persons undergoing correction of hyperopia (seven of 14 eyes vs. none of 217 eyes undergoing myopic LASIK, P <.001). The only difference identified between procedures was use of masks created from a soft contact lens in hyperopic LASIK. Three isolates (three patients) were indistinguishable by pulsed-field gel electrophoresis. Eyes were treated with a combination of antimicrobial agents, including topical azithromycin in three patients, with resolution of infection in all eyes over 6 to 14 weeks. The source of infection was not identified on environmental cultures.

CONCLUSION

Postoperative nontuberculous mycobacterial keratitis can occur in an epidemic fashion following LASIK. Topical amikacin, azithromycin, clarithromycin, ciprofloxacin, or a combination of these agents, appears to be effective treatment for these infections.

Atrophic fundus lesions associated with untreated retinopathy of prematurity

PURPOSE

To document that lacunar, atrophic lesions of the retinal pigment epithelium, previously reported as a complication of treatment, can result from the natural course of retinopathy of prematurity.

METHODS

We reviewed photographs of patients diagnosed with retinopathy of prematurity at the Casey Eye Institute between 1979 and 1996. Lacunar atrophic lesions of the retinal pigment epithelium were correlated with the clinical records of the affected patients.

RESULT

Three untreated eyes of three patients with retinopathy of prematurity had lacunar atrophic lesions of the retinal pigment epithelium.

CONCLUSIONS

The spectrum of findings associated with untreated retinopathy of prematurity includes lacunar, atrophic lesions of the retinal pigment epithelium. These lesions are distinct from scars secondary to treatment and are possibly linked to macular dragging and exudative or serous retinal detachment.

Intravitreal injection of octreotide acetate

This study was conducted to determine the feasibility of injecting the somatostatin analogue, octreotide acetate (OA), into the vitreous cavity. Previous work suggests that octreotide effectively inhibits angiogenesis in vitro, thus its use in vivo may slow the progression of proliferative eye disease. Fifty micrograms of aqueous OA in 50 microliters aqueous solution was injected into the mid-vitreous of kitten eyes (n = 6), and OA levels were monitored over 4 days. A long-acting release form of octreotide (OA-LAR) was also injected into the mid-vitreous of rabbit eyes at doses of 0.36 (n = 16), 1.1 (n = 1), 2.1 (n = 1), 4.05 (n = 1), 8.2 (n = 1), and 36 mg (n = 3) in solution; and octreotide concentrations were measured at various time points over 42 days. OA concentrations were determined by a highly specific radioimmunoassay. Aqueous octreotide was eliminated rapidly (t1/2 = 16 hours) from the vitreous of the kitten eye, with only negligible amounts recoverable 4 days post-injection. In the long-acting form, OA in the rabbit eye reached peak levels at 28 days. By 42 days, OA levels had declined to the 14-day level. Doses of OA-LAR of 1.1 mg or less produced no gross evidence of clinical toxicity and elicited no grossly visible ocular side effects. Doses greater than 1.1 mg produced significant toxicity, including cataracts and rubeosis. The 28-day peak release for long-acting OA implies that monthly intravitreal injections could provide continual high levels of OA. Intravitreal injection of long-acting OA provides sustained, high concentrations of drug, and deserves further study as a potential treatment of proliferative eye diseases.