Final analysis of phase II results with cemiplimab in metastatic basal cell carcinoma after hedgehog pathway inhibitors.

BACKGROUND: Metastatic basal cell carcinoma (mBCC) is a rare condition with no effective second-line treatment options. Cemiplimab is an immune checkpoint inhibitor that blocks the binding of programmed cell death-1 (PD-1) to its ligands, programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2). Here, we present the final analysis of cemiplimab in patients with mBCC after first-line hedgehog pathway inhibitor (HHI) treatment (NCT03132636). PATIENTS AND METHODS: In this open-label, single-arm, phase II study, adults with mBCC and Eastern Cooperative Oncology Group performance status ≤1, post-HHI treatment, received cemiplimab 350 mg intravenously every 3 weeks for ≤93 weeks or until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by independent central review (ICR). Duration of response (DOR) was a key secondary endpoint. Other secondary endpoints were ORR per investigator assessment, progression-free survival (PFS), overall survival (OS), complete response rate, safety, and tolerability. RESULTS: Fifty-four patients were enrolled: 70% were male and the median age of patients was 64 [interquartile range (IQR) 57.0-73.0] years. The median duration of follow-up was 8 months (IQR 4-21 months). The ORR per ICR was 22% [95% confidence interval (CI) 12% to 36%], with 2 complete responses and 10 partial responses. Among responders, the median time to response per ICR was 3 months (IQR 2-7 months). The estimated median DOR per ICR was not reached [95% CI 10 months-not evaluable (NE)]. The disease control rate was 63% (95% CI 49% to 76%) per ICR and 70% (95% CI 56% to 82%) per investigator assessment. The median PFS per ICR was 10 months (95% CI 4-16 months); the median OS was 50 months (95% CI 28 months-NE). The most common treatment-emergent adverse events were fatigue [23 (43%)] and diarrhoea [20 (37%)]. There were no treatment-related deaths. CONCLUSIONS: Cemiplimab demonstrated clinically meaningful antitumour activity, including durable responses, and an acceptable safety profile in patients with mBCC who had disease progression on or intolerance to HHI therapy.

The controversy on the early history of Chagas disease.

Recently historians of medicine have proposed three distinctive accounts of early history of Chagas disease (American trypasonomiasis). According to the first the disease, described by the Brazilian researcher Carlos Chagas in 1909, was "deconstructed" in the 1920s and disappeared for about twenty years, then was recovered in the 1940s, mainly through the epidemiological studies of Emmanuel Dias and his colleagues in Minas Gerais (Brazil). According to the second Chagas disease could not be "deconstructed" in the 1920s because it did not exist at that time. Chagas observations were inaccurate and unreliable and did not define a new human pathology. The entity called today "Chagas disease" appeared in the 1930, principally as the result of investigations of Cecilio Romaña in Argentina. Finally, a third view assumes that "Chagas disease" was constructed gradually between 1909 and the 1950s through the collective efforts of numerous Latino-American researchers. This paper juxtaposes different histories of Chagas disease, and argues that their divergences stems from allegiance to distinct, partly incommensurable epistemological "thought styles". The co-existence of divergent styles of historical investigation, this text proposes, should be perceived as potential source of enrichment of our understanding of the past.

Single-dose safety, pharmacology, and antiviral activity of the human immunodeficiency virus (HIV) type 1 entry inhibitor PRO 542 in HIV-infected adults.

PRO 542 (CD4-IgG2) is a recombinant antibody-like fusion protein wherein the Fv portions of both the heavy and light chains of human IgG2 have been replaced with the D1D2 domains of human CD4. Unlike monovalent and divalent CD4-based proteins, tetravalent PRO 542 potently neutralizes diverse primary human immunodeficiency virus (HIV) type 1 isolates. In this phase 1 study, the first evaluation of this compound in humans, HIV-infected adults were treated with a single intravenous infusion of PRO 542 at doses of 0.2-10 mg/kg. PRO 542 was well tolerated, and no dose-limiting toxicities were identified. Area under the concentration-time curve, and peak serum concentrations increased linearly with dose, and a terminal serum half-life of 3-4 days was observed. No patient developed antibodies to PRO 542. Preliminary evidence of antiviral activity was observed as reductions in both plasma HIV RNA and plasma viremia. Sustained antiviral effects may be achieved with repeat dosing with PRO 542.

[Paul-Louis Simond and yellow fever]. / Paul-Louis Simond et la fièvre jaune.

P.L. Simond participated in the Pasteur Institute mission sent to Rio de Janeiro from 1901 to 1905 to investigate yellow fever and was to make an important contribution to the knowledge of the disease. At that time, the aetiologic agent of yellow fever was still unknown, and its transmission by mosquitoes was controversial. Several authors had observed apparent differences in the susceptibility to the illness between African and European populations. Otherwise, the soundness of epidemic control measures then being administered was often called into question. As such, many points needed to be definitely clarified. During the four years they spent in Brazil, the Pasteur Institute scientists--and particularly Simond--achieved important results. They confirmed the viral aetiology of yellow fever, were able to define several pathological aspects of the disease and conduct various serotherapeutic tests. The role of Aedes aegypti (known at the time as Stegomyia fasciata) was also confirmed and the bionomics of the mosquito began to be studied. This research laid the ground for classical measures of controlling the vector and preventing outbreaks of the disease. Furthermore, Marchoux and Simond observed the vertical transmission of yellow fever virus in Ae. aegypti; this phenomenon of major epidemiological importance remained controversial until it was confirmed in the field as recently as 1997. The French scientists were also able to specify many aspects of the epidemiology of yellow fever, particularly its apparent low pathogenicity in young children--a possible explanation for the fact that local residents of endemic zones often had a certain level of immunity as a result of benign infection contracted in childhood. P.L. Simond later spent several months in Martinique where he set up a successful yellow fever vector control programme. Clearly Simond, who had already acquired much expertise in the epidemiology of vector-borne diseases, played a key role in the success of the mission sent by Institute Pasteur to Brazil, and, more generally, in the scientific advances of yellow fever prevention.

[Representing and intervening in public health: viruses, mosquitoes and Rockefeller Foundation experts in Brazil]. / Representação e intervenção em saúde pública: vírus, mosquitos e especialistas da Fundação Rockefeller no Brazil.

The attempts by experts from the of the Rockefeller Foundation (RF) to eliminate yellow fever in Brazil were hampered by the pathology's low visibility. Most cases of yellow fever were atypical and easily confused with other fevers. In the 1920s, the RF experts who tried to assess the presence of yellow fever relied mainly on clinical observations. In the 1930s, however, they devised indirect methods of visualizing the presence of the disease agent. Visceroctomy revealed the presence of acute cases of the disease. Mouse protection tests revealed past contacts with the agent. Taken together, these tests enabled the RF specialists to construct maps which indicated zones where the disease was endemic and to target specific anti-yellow fever campaigns based on selective elimination of the yellow fever vector, that is, the mosquito Aedes aegypti. In public health, like in the sciences, representation practices shape intervention.

Effects of mutations in Pr160gag-pol upon tRNA(Lys3) and Pr160gag-plo incorporation into HIV-1.

During HIV-1 viral assembly, both Pr160gag-pol and primer tRNA(Lys3) are packaged into the virus. tRNA(Lys) packaging (both tRNA(Lys3) and tRNA(Lys1,2) is dependent upon the presence of RT sequences within Pr160gag-pol. In this work, we have monitored the effect of Pr160gag-pol mutations upon incorporation of tRNA(Lys3) and Pr160gag-pol into HIV-1 produced from COS-7 cells transfected with mutant HIV-1 proviral DNAs. Mutations include carboxy deletions of Pr160gag-pol and small amino acid insertions and replacements within the various functional domains of the reverse transcriptase (RT). tRNA(Lys3) incorporation was monitored both by 2D PAGE of viral RNA, and by hybridization with tRNA(Lys3)-specific DNA probes. Our data indicates: (1) deletion of integrase sequence has a moderate effect upon select tRNA(Lys3) packaging, while carboxy terminal deletions extending further into the RNase H and connection domains more strongly reduce viral tRNA(Lys3) content; (2) tRNA(Lys3) incorporation is strongly reduced by small inframe amino acid insertions or replacements in the carboxy region of the thumb domain and the amino half of the connection domain of RT, but tRNA(Lys3) incorporation is altered little, or not at all, by similar amino acid insertional mutations within other RT domains, such as the fingers, palm, RNase H, the amino portion of the thumb, and the carboxy region of the connection domain. The inability of connection domain mutant virus to incorporate tRNA(Lys3) and to properly process precursor proteins in the virus is due to the inability of mutant Pr160gag-pol to be incorporated into the virus. These mutant precursor proteins are maintained at levels in the cytoplasm similar to wild-type.

Herpesvirus saimiri-transformed human CD4+ T cells can provide polyclonal B cell help via the CD40 ligand as well as the TNF-alpha pathway and through release of lymphokines.

We have developed human CD4+ T cell lines from the PBL of normal donors by infection with Herpesvirus saimiri (HVS), to evaluate functional properties of these immortalized lymphocytes. In this report, we characterize two such CD4+ T cell lines, CHCD4 and MHCD4, which were derived from two different donors. These cells grew independent of exogenous IL-2 stimulation for over 1 yr, and expressed surface markers (CD25+, CD69+, HLA-DR+, and B7+) associated with an activated T cell phenotype. Both lines constitutively produced and released IFN-gamma, but no IL-2 or IL-4. However, the surface expression of the two cell lines differed in that CHCD4 constitutively expressed CD40 ligand (CD40L) and membrane TNF-alpha, but MHCD4 did not. Also, CHCD4, but not MHCD4, potently induced polyclonal B cell activation and differentiation in the absence of PWM, in an MHC-unrestricted fashion. The B cell help afforded by CHCD4 included contact-dependent and soluble components. Contact-dependent help was strongly inhibited by mAb against CD40L (5C8) and to a lesser extent, by anti-TNF-alpha Ab. The CD40L-dependent helper function of CHCD4 contrasts with the recent description of other HVS-transformed CD4+ T cells that provide B cell help primarily via the membrane TNF-alpha and TNF-alphaR pathways. Furthermore, CHCD4 cells also secreted soluble factors that could mediate CD40-linked B cell differentiation into Ab-producing cells. Interestingly, this factor is not likely to be IL-2, IL-4, IL-6, IL-10, IL-15, TNF-alpha, or IFN-gamma as Abs against these cytokines were not able to inhibit the contact-independent B cell help by CHCD4. These results indicate that HVS-immortalization of CD4+ lymphocytes may produce T cell clones with a spectrum of important contact-dependent, as well as contact-independent, B cell helper function capacities.

[Metaphors of immunology: war and peace]. / Les métaphores de l'immunologie: guerre et paix.

Immunology has always relied on metaphorical language. In its early beginnings, it varied between bellicose images and images that stressed the interaction of immunity mechanisms with the organism's physiological functions overall. In the late nineteenth century, white blood globules were not only compared to 'border police' assigned to rebuffing intruders -- an army formed to combat the invaders -- but were also described as a physiological mechanism for eliminating aged, dead cells, at times exterminators of foreign bodies. Antibodies were described as very powerful, deadly weapons but also as an integral part of mechanisms that allowed cells to assimilate food. This duality of images holds true today. The article analyzes the emergence and development of these images, relating them to the redefinition of immunology as a science of the self and non-self and dissecting them in light of recent events, such as the Aids epidemic.

Polydeoxyguanine motifs in a 12-mer phosphorothioate oligodeoxynucleotide augment binding to the v3 loop of HIV-1 gp120 and potency of HIV-1 inhibition independency of G-tetrad formation.

Phosphorothioate oligodeoxynucleotides belong to a class of polyanions that bind to the third variable domain (v3) of HIV-1 gp120 and inhibit infectivity of a wide variety of HIV-1 isolates. This potent v3 binding of phosphorothioate oligodeoxynucleotides, which is relatively independent of the nucleotide sequence of the oligodeoxynucleotides, decreases with chain length (below 18-mers) and is low for 8-mers. However, recent studies have observed a nucleotide sequence-dependent augmentation of phosphorothioate oligodeoxynucleotide binding to v3 for 8-mers that contain the S-dG4 motif (e.g., SdT2G4T2) and have suggested that formation of quadruple helical tetraplexes (G-tetrads) is associated with the acquisition of v3 binding ability by small phosphorothioate oligodeoxynucleotides. In the current study, a series of SdG4-containing oligodeoxynucleotides were synthesized with varying tandem length (including the 8-mer SdT2G4T2, the 12-mer SdG4T4G4, and the 28-mer SdG4(T4G4)3) and compared with phosphorothioate oligodeoxynucleotides (with similar lengths or related sequences) for (1) their inhibition of the binding of mAb 9284, which binds to the N-terminal portion of the v3 loop, (2) the values of Kc when these compounds are used as competitors of the rgp120-binding of an alkylating phosphodiester oligodeoxynucleotide probe, and (3) inhibition of HIV-1 infectivity in a cell-cell transmission model. The presence of S-dG4 motifs and the number of tandem motifs augmented v3 binding and anti-HIV-1 infectivity for small (8-mer or 12-mer oligodeoxynucleotides) but did not significantly augment the potency of 28-mers. Whereas tetraplex formation of SdT2G4T2 may contribute to its v3 binding, the 12-mer SdG4T4G4 does not migrate as the tetraplex on nonreducing gels, suggesting that S-dG4 motifs may augment anti-HIV activity by multiple mechanisms.

"Nothing more to be done": palliative care versus experimental therapy in advanced cancer.

Patients suffering from advanced, incurable cancer often receive from their doctors proposals to enroll in a clinical trial of an experimental therapy. Experimental therapies are increasingly perceived not as a highly problematic approach but as a near-standard way to deal with incurable cancer. There are, however, important differences in the diffusion of these therapies in Western countries. The large diffusion of experimental therapies for malignant disease in the United States contrasts with the much more restricted diffusion of these therapies in the United Kingdom. The difference between the two reflects differences in the organization of health care in these countries and distinct patterns of the professionalization of medical oncology in America and in Britain. The high density and great autonomy of medical oncologists in the United States encourages there the diffusion of experimental therapies (regarded by some as expensive and inefficient); the lower density of these specialists in the United Kingdom and their task as consultants and not primary caregivers, favors the choice of more conservative (for some, too conservative) treatments. Theoretically, the decision as to whether patients suffering from advanced, incurable cancer will be steered toward an experimental therapy or toward palliative care depends on the values and beliefs of these patients and their physicians. In practice, however, such choice does not depend exclusively on the individual's cultural background and ethical values, but is also strongly affected by the--culturally conditioned--professional and institutional structure of medicine.

Linker insertion mutations in the human immunodeficiency virus type 1 gag gene: effects on virion particle assembly, release, and infectivity.

The phenotypes of a series of mutant human immunodeficiency virus type 1 proviruses with linker insertion and deletion mutations within the gag coding region were characterized. These mutants were tested for their ability to make and release viral particles in COS7 cells and for their viability in vivo. Of the 12 mutant proviruses, 4 did not make extracellular virion particles when transfected into COS7 cells. All four of these mutants had mutations in the C-terminal domain of CA. These mutants appeared to have defects both in the ability to accumulate high-molecular-weight intracellular structures containing Gag and Pol products and in the ability to release virion particles. Seven of the mutant proviruses retained the ability to make, release, and process virion particles from COS7 cells. These particles contained the Env glycoprotein, viral genomic RNA, and the mature products of the Gag and Gag-Pol polyproteins, yet they were noninfectious or poorly infectious. The defect in these mutants appears to be in one of the early steps of the viral life cycle. Thus, multiple regions throughout Gag appear to be important in mediating the early steps of the viral life cycle.

Expression of a Tat-inducible herpes simplex virus-thymidine kinase gene protects acyclovir-treated CD4 cells from HIV-1 spread by conditional suicide and inhibition of reverse transcription.

Cellular expression of the herpes simplex virus type 1 thymidine kinase (HSV1-TK) gene promotes cell death in the presence of specific nucleoside analog substrates such as acyclovir (ACV). We have reported that lymphoid CD4+ cells harboring an HSV1-TK gene, under the transcriptional control of the HIV-1 long terminal repeat (HUT-TK), are completely protected from HIV-1 spread in the presence of 10 microM ACV. In this report we clarify the efficiency, generality, and mechanism of this protective effect. We show that the protection from HIV-1 spread in HUT-TK cells obtains from both an inhibition of HIV reverse transcription by ACV metabolites and an HIV-induced and ACV-dependent cell killing. We also demonstrate that monocytic cells harboring the HIV-1-inducible HSV1-TK gene are protected from HIV spread in the presence of ACV. These observations facilitate the design of therapeutic strategies to limit HIV replication based on HSV1-TK expression.

[Scientific facts and their public: the history of the diagnosis of syphilis]. / Les "faits scientifiques" et leur public: l'histoire de la détection de la syphilis.

In the 1910's and 1920', thanks to the conjunction of scientific views concerning the specificity of anti-bacterial antibodies, of lay ideas about the existence of anti-bacterial antibodies and of the perceived importance of developing a syphilis test for public health officials, the community of serologists collectively transformed a relatively inefficient diagnostic test described by Wassermann in 1906 into an "incontestable scientific fact". This "scientific fact" established the equivalence: Wassermann positive individual=person infected with the germ Treponema pallidum, the etiological agent of syphilis. It modified the boundaries of the nosologic entity "syphilis", medical practices, professional attitudes, lay perceptions of syphilis, and health policies. In the 1950's, however, discrepancies between Wassermann test data and epidemiological data and, on the other hand, the development of specific anti-treponemal tests, destabilized the previously stabilized "scientific fact". A high percentage of Wassermann positive individuals were redefined as "biological false positifs", that is persons who suffered from chronic affections able to induce positive results of the Wassermann test. The equivalence Wassermann positive person=individual infected by Treponema pallidum was replaced by the equation: Wassermann positive person=individual infected by Treponema pallidum or biological false positive. The new perception of the Wassermann test again changed scientific views, professional practices and lay beliefs. The history of the Wassermann reaction illustrates the complicated interaction between "scientific facts" and "social facts", and the mutual shaping of both.

Cellular thymidine kinase activity is required for the inhibition of HIV-1 replication by AZT in lymphocytes.

In this report, we provide evidence that the cellular thymidine kinase activity is required for the inhibition of HIV replication by zidovudine (AZT) in lymphocytes. The HSV-1 thymidine kinase protein is not able to substitute for the cellular enzyme, in accord with in vitro data that AZT is poorly phosphorylated by the HSV-derived activity.

[Ludwik Fleck and the history of sciences today]. / Ludwik Fleck e a presente história das ciências.

In the 1920's and 30's the physician and epistemologist Ludwik Fleck developed a highly original ideas on science. These ideas were rooted in Fleck's own experience as bacteriologist and immunologist and, on the other hand, in the practice-based thought of the Polish School of Philosophy of Medicine. Fleck affirmed that 'scientific facts' are constructed by groups of scientists, in his terms, by "thought collectives". Each thought collective elaborates a "thought style" which contains norms, concepts and practices of that collective. Newcomers to a professional community are socialized into its specific thought style and develop an unique way of viewing the world. Scientific facts produced by a given thought collective are therefore shaped by that collective's thought style, and are incommensurable with facts produced by other thought collectives. The incommensurability of scientific facts and its consequence, the need to 'translate' these facts into the style of different thought collectives in an inter-community use are, Fleck proposed, an important source of innovations in science and in society. Fleck ideas were rediscovered in the 1960's and 70's, first by Thomas Kuhn, who in the introduction to his book, The structure of scientific revolutions, acknowledges his ties with Fleck's thought, then by sociologists of science. Beyond their direct influence, Fleck's epistemology has many affinities with new trends in science studies, focused on the scientists' practices, and interested in their material, discursive and social techniques.

Transcellular activation of the human immunodeficiency virus type 1 long terminal repeat in T lymphocytes requires CD4-gp120 binding.

Cells expressing human immunodeficiency virus type 1 (HIV-1) tat can transactivate the HIV-1 long terminal repeat (LTR) in cocultured T lymphocytes. In this report, we describe the molecular requirements for transcellular activation of the LTR in Jurkat cells. An analysis with deletion mutants and blocking antibodies demonstrated a requirement for env expression in addition to tat expression for transcellular activation to occur. The results suggest that the transient association of CD4 and gp120 in cocultured cells is required for tat-mediated transcellular activation. The events that follow CD4-gp120 binding in transactivation, however, do not require the gp120-neutralizing domain, in contrast to HIV-mediated fusion and infection. The consequences of this interaction on cellular function are currently under investigation.