Mutations in RAS oncogenes (KRAS, HRAS, NRAS) are among the most common genetic alterations in human cancers. The activating KRASG12C mutation, in particular, is a key driver in a significant percentage of non-small cell lung cancer (NSCLC), pancreatic ductal adenocarcinoma (PDAC), colorectal cancer, and lung adenocarcinoma. While KRAS was long considered undruggable, the development of mutant-specific inhibitors, including covalent inhibitors targeting KRASG12C (such as Sotorasib and Adagrasib) and non-covalent inhibitors targeting KRASG12D (such as Mirati’s MRTX1133), has shown promise. These inhibitors function by binding to a shallow pocket between the switch-I and switch-II elements, locking KRAS in its inactive GDP-bound state. However, concerns exist regarding the efficacy and the development of resistance to Sotorasib and Adagrasib through mechanisms like secondary mutations, KRAS overexpression, and KRAS downstream pathway activation. To overcome these limitations, we developed a novel, stimuli-sensitive, tumor microenvironment-activated, ferritin-derived nanomedicine platform, named The-05. This platform, previously shown to effectively enhance payload biodistribution, plasma half-life, and reduce off-target effects in various tumors, is reported here to: 1) encapsulate high amounts of the KRASG12C inhibitor Adagrasib and the PROTAC degrader LC-2; 2) to achieve efficient intracellular delivery in vitro, once activated by matrix metalloproteases MMP-2 and MMP-9. In cellular models of KRAS-mutated NSCLC and PDAC, this nanoplatform achieved comparable or superior therapeutic outcomes with respect to the individual drugs. This study provides a compelling proof-of-concept for the in vitro delivery of KRASG12C mutant-specific inhibitors and degraders to human tumors through a tumor microenvironment-activated nanomedicine approach and lays the groundwork for future studies in physiologically relevant models to assess TME-specific activation and tumor selectivity.

Activating KRAS mutations, particularly G12 variants, are key drivers in pancreatic ductal adenocarcinoma and other cancers. While KRAS was historically considered undruggable, mutant-specific inhibitors, including non-covalent KRAS G12D inhibitor MRTX1133, have emerged. However, efficacy and resistance remain challenges. We utilized a stimuli-sensitive, ferritin-derived nanomedicine platform to encapsulate high concentrations of MRTX1133, aiming for targeted delivery of the drug to KRAS-mutated pancreatic ductal adenocarcinoma cells. This platform, designed for enhanced biodistribution and reduced off-target effects, achieved a major efficacy over free MRTX1133 in 2D models regarding cell proliferation and KRAS inhibition pathway and, in 3D spheroid models, specifically concerning cell death. Efficacy in patient-derived organoids was comparable. This study demonstrates the potential of this nanomedicine platform for targeted delivery of KRAS mutant-specific inhibitors to human tumors.

Crouzon syndrome is a rare genetic craniofacial malformation caused by heterozygous gain-of-function mutations in the FGFR2 gene. The resulting constitutive activation of the FGFR2 signaling causes the premature osteogenic differentiation of calvarial mesenchymal stromal cells in skull sutures, leading to early suture ossification. Craniectomy is the gold standard treatment, being invasive and burdened by complications. To address these issues, we developed personalized allele-specific (AS) small interfering RNA (siRNA) to knockdown the expression of the FGFR2 mutant allele in Crouzon patient-derived suture cells. The selected therapeutic siRNA mitigated FGFR2 cascade downregulating phosphorylation of FGFR2 (48%) and of its key effector ERK1/2 (77%) as RUNX2 protein levels (34%). This effect was confirmed by the reduced osteogenic commitment and differentiation of treated cells, evidenced by decreased expression of osteogenic marker genes and a 5-fold decrease in mineralized matrix deposition. We developed a highly biocompatible delivery system for siRNAs, based on human recombinant ferritin nanoparticles (NPs), combining cell targeting with improved nucleic acid encapsulation and endosomal escape properties. We demonstrated the ability of these NPs to deliver and release siRNAs within target cells, sustaining their inhibitory and AS effects. Here, we show that ferritin-mediated AS FGFR2 knockdown by siRNA represents a suitable strategy to dampen FGFR2 overactivation in patients’ cells.

Cancer is a complex illness with local to systemic expression. Cancer cells in relation with the constitutive components of the tissue from which they develop and the immune system elements, that interact with them to ablate the cancer cells and promote tissue repair, form the tumor microenvironment. The interactions between all these elements decide the tumor evolution either toward its elimination (inflammation, immune recognition and direct cytotoxicity) or its establishment and progression (inversion of the immune response, chronic and smoldering inflammation, immune cell exhaustion and establishment of an immune suppressive and tissue remodeling environment). The alteration of the tissue collagen scaffold influenced by the immune environment continuous modifications collaborates to impede adequate access to immune cells and drugs and solicitate epithelial to mesenchymal transition allowing metastatic cell behavior. Under these conditions, the altered immune environment can bias the efficacy of the treatments and favor the tumor heterogeneity. Many therapeutic approaches were developed, from surgery to chemo- and radiotherapy until the recent advances in immunotherapy. However, if the therapeutic approach is systemic, sensible side effects can accompany the treatment because of the involvement also of non-tumoral tissues. Therefore, from the last years of the XX century, a progressive interest and improvement in technical possibilities started to focus on targeting therapies using monoclonal antibodies (e.g. against cellular pathways, growth-factors, immune check-point molecules) and/or organic/inorganic nano-constructs (e.g. ferritin-based, iron-based nanoparticles) studied for directly affect the cancer cells or other microenvironment components (immune cells). Focusing the intervention to the pathological component and selectively foster the anticancer response is the aim of modern oncology. In this presentation, we will highlight some of our observations done on components of the microenvironment favoring the tumor escape and our experience of tumor targeting by nanoparticles in experimental models looking to achieve more tumor and antigen specific treatments for enhancing the anti-cancer immune response, possibly with a patient-tailored approach. Acknowledgements: we thanks the support by Institutional Grant RVO 61388971 (CZ), GAAV IAA500200917 (CZ), AZV NU23-08-00071 (CZ), MEYS CR (Large RI Project LM2018129 Czech-BioImaging), ERDF (project No. CZ.02.1.01/0.0/0.0/18_046/0016045) and the project National Institute for Cancer Research (Programme EXCELES, ID Project No. LX22NPO5102) - Funded by the European Union –Next Generation EU, Generali Ceska Pojistovna Foundation (CZ), UniCredit Bank (CZ), SIAD s.r.o. (ITA/CZ), GITCO s.r.o (CZ), CONTAS s.r.o (CZ), CAMIC a.s. (CZ)

To address the challenge of drug accumulation and penetration at the tumor site(s), herein we describe a first-in-class nanocarrier containing 24 copies each of two bioactive peptides (BAPs) genetically fused in frame to the 24 N-termini of a human ferritin H-type construct, named THE-10. The two BAPs are specific for PD-L1 and integrin αVβ3/αVβ5 plus Neuropilin (iRGD) respectively, conferring immune checkpoint blockade and drug-internalization properties. In turn, the THE-10 backbone brings 48 BAPs contiguous for synergism, prolonged blood half-life, and release into the tumor microenvironment upon conditional cleavage of a metalloprotease-sensitive site. Predicted THE-10 multitasking activity was experimentally supported as follows. Size-exclusion chromatography and surface plasmon resonance demonstrated BAP cleavage/release and receptor binding (nanomolar KD). Live-cell/time-lapse imaging demonstrated 4-fold-increased internalization of naked therapeutic antibodies, mirrored by enhanced cytotoxicity of the corresponding Antibody-Drug Conjugate. Slight antitumor effects were observed in vivo by treating immune checkpoint-sensitive syngeneic mouse colorectal model with THE-10 alone. Drug boosting was instead considerable on colorectal and pancreatic tumor allografts when THE-10 was co-administered with both small and large chemotherapeutic agents, outperforming the original iRGD cyclic peptide. Thus, THE-10 may enhance target therapy, chemotherapy and immunotherapy altogether, e.g. it candidates as a multitasking, all-round, antineoplastic therapy booster.

Group 3 (G3) is one of the most common and aggressive subtypes of the paediatric cerebellar tumour Medulloblastoma (MB), primarily driven by the MYC oncogene. The challenging targeting of MYC, coupled with gaps in understanding G3 MB molecular bases, has hindered the development of targeted therapies. The unconventional oncogenic roles of long noncoding RNAs (lncRNAs) offer opportunities to address this complexity, to provide insights and to identify novel targets. Using -omics approaches and molecular/cellular assays, we elucidate the mode-of-action of lncMB3, a MYC-dependent, anti-apoptotic lncRNA in G3 MB. LncMB3 regulates the TGF-β pathway, critically altered in G3 medulloblastomagenesis, via direct binding and translational inhibition of the mRNA for the epigenetic factor HMGN5. This regulatory axis affects apoptosis through photoreceptor lineage genes, including the G3 driver OTX2. The synergistic effects between lncMB3 targeting and cisplatin treatment underscore the relevance of this network. Additionally, we propose novel ferritin-based nanocarriers for the efficient delivery of antisense oligonucleotides against lncMB3. LncMB3 crucially links MYC amplification and apoptosis inhibition through a circuit involving RNA-based mechanisms, G3 MB key determinants and underexplored factors. This integrated framework deepens the understanding of G3 MB landscape and supports the potential for translating lncRNA research into future applications.

Spastin is a microtubule (MT) severing enzyme that regulates several cell functions associated with MT dynamics. A reduction in spastin protein levels is responsible for approximately 40% of cases of Hereditary Spastic Paraplegia (HSP), a neurodegenerative disease. Currently, there is no cure for HSP but strategies to induce a recovery of spastin levels are emerging as potential therapeutic approaches. Here, we show that MDM2 interacts with spastin MT-interacting and trafficking (MIT) domain. By biochemical and functional experiments, we demonstrate that MDM2 binds spastin and regulates its levels in a post-transcriptional manner independently of the E3 ubiquitin ligase activity. Of relevance, treatment of spastin-deficient cells with the MDM2 inhibitor Nutlin-3a can restore spastin levels and functions, such as cytokinetic abscission and sorting of transferrin receptor. These findings identify MDM2 as a novel interactor of spastin and a potential druggable regulator of its protein levels.

Background. Group 3 (G3) is one of the most common, aggressive and fatal subtypes of the paediatric cerebellar tumour Medulloblastoma (MB), primarily driven by the MYC oncogene. Targeting MYC has long been challenging and this, combined with our incomplete understanding of G3 MB molecular bases, has hindered the development of effective targeted therapies. Long noncoding RNAs (lncRNAs), with their extensive oncogenic roles, cancer-specific expression, and connection to MYC biology, offer opportunities for unravelling this complexity and providing new insights and therapeutic targets. Methodology. Using genome-wide, molecular and cellular assays, we characterised the activity of the MYC-dependent, anti-apoptotic lncRNA lncMB3 in G3 MB cells. Results. Through transcriptomic and interactomic analyses, we clarified lncMB3 function and mode-of-action. LncMB3 controls the TGF-β pathway, critically altered in G3 medulloblastomagenesis. This regulation occurs via the direct coding-noncoding RNA interaction between lncMB3 and the mRNA for the epigenetic factor HMGN5, with both sharing targets in the TGF- β cascade. This axis converges on apoptosis through OTX2, another G3 MB driver gene, and photoreceptor lineage genes. Synergistic effects between lncMB3 targeting and cisplatin treatment underscores the relevance of this regulatory network in vitro. Finally, we propose novel ferritin-based nanocarriers as efficient delivery tools for antisense oligonucleotides targeting lncMB3. Conclusions. LncMB3 emerges as a central node linking MYC amplification to apoptosis inhibition through a circuit involving RNA-based mechanisms, G3 MB key drivers and underexplored factors. This integrated framework deepens our understanding of G3 MB molecular underpinnings and lay the foundation for translating lncRNA research into potential applications. ### Competing Interest Statement The authors have declared no competing interest.

Gliomas are among the most fatal tumors, and the available therapeutic options are very limited. Additionally, the blood-brain barrier (BBB) prevents most drugs from entering the brain. We designed and produced a ferritin-based stimuli-sensitive nanocarrier with high biocompatibility and water solubility. It can incorporate high amounts of the potent topoisomerase 1 inhibitor Genz-644282. Here, we show that this nanocarrier, named The-0504, can cross the BBB and specifically deliver the payload to gliomas that express high amounts of the ferritin/transferrin receptor TfR1 (CD71). Intranasal or intravenous administration of The-0504 both reduce tumor growth and improve the survival rate of glioma-bearing mice. However, nose-to-brain administration is a simpler and less invasive route that may spare most of the healthy tissues compared to intravenous injections. For this reason, the data reported here could pave the way towards a new, safe, and direct ferritin-based drug delivery method for brain diseases, especially brain tumors.

Background:Cancer is still among the leading causes of death all over the world. Improving chemotherapy and minimizing associated toxicities are major unmet medical needs. Recently, we provided a preliminary preclinical evaluation of a human ferritin (HFt)-based drug carrier (The-0504) that selectively delivers the wide-spectrum topoisomerase I inhibitor Genz-644282 to CD71-expressing tumors. The-0504 has so far been evaluated on four different human tumor xenotransplant models (breast, colorectal, pancreatic and liver cancers). Methods:Herein, we extend our studies, by: (a) testing DNA damage in vitro, (b) treating eight additional tumor xenograft models in vivo with The-0504; (c) performing pharmacokinetic (PK) studies in rats; and (d) evaluating The-0504 anti-tumor xenotransplant efficacy by optimizing its administration schedule based on PK considerations. Results:Immunofluorescence demonstrated that The-0504 induces foci expressing the DNA double-strand break marker γH2AX. Expression increases up to 4-fold and is more persistent as compared to free Genz-644282. In vivo studies confirmed a remarkable anti-tumor activity of The-0504, resulting in tumor eradication in most murine xenograft models, regardless of embryological origin (e.g. epithelial, mesenchymal or neuroendocrine), and molecular subtypes. PK studies demonstrated a long persistence of The-0504 in rat serum (half-life of about 40 h as compared to 15 h of the free drug), with a 400-fold increase in peak concentrations as compared to the free drug. On this basis, we reduced The-0504 administration frequency from twice to once per week, with no appreciable loss in therapeutic efficacy in mice. Conclusion:The results presented here confirm that The-0504 is highly active against several human tumor xenotransplants, even when administered less frequently than previously reported. The-0504 may be a good candidate for further clinical development in a tumor histotype-agnostic setting.

Background Ferritin receptor (CD71) is an example of a very attractive cancer target, since it is highly expressed in virtually all tumor types, including metastatic loci. However, this target can be considered to be inaccessible to conventional target therapies, due to its presence in many healthy tissues. Here, we describe the preclinical evaluation of a tumor proteases-activatable human ferritin (HFt)-based drug carrier (The-0504) that is able to selectively deliver the wide-spectrum topoisomerase I inhibitor Genz-644282 to CD71-expressing tumors, preventing the limiting toxic effects associated with CD71-targeting therapies. Methods CD71 expression was evaluated using flow cytometry and immunohistochemistry techniques. The-0504 antiproliferative activity towards several cancer cell lines was assessed in vitro. The-0504 antitumor efficacy and survival benefit were evaluated in different human tumors, which had been grown either as xenografts or patient-derived xenografts in mice. The-0504 toxicology profile was investigated in multiple-cycle repeat-dose study in rodents. Results In vitro studies indicate that The-0504 is highly specific for CD71 expressing cells, and that there is a relationship between CD71 levels and The-0504 anticancer activity. In vivo treatments with The-0504 showed a remarkable efficacy, eradicating several human tumors of very diverse and aggressive histotypes, such as pancreas, liver and colorectal carcinomas, and triple-negative breast cancer. Conclusions Durable disease-free survival, persistent antitumor responses after discontinuation of treatment and favorable toxicology profile make The-0504 an ideal candidate for clinical development as a novel, CD71-targeted, low-toxicity alternative to chemotherapy.

Pancreatic cancer (PC) represents an intriguing topic for researchers. To date, the prognosis of metastasized PC is poor with just 7% of patients exceeding a five-year survival period. Thus, molecular modifications of existing drugs should be developed to change the course of the disease. Our previously generated nanocages of Mitoxantrone (MIT) encapsulated in human H-chain Ferritin (HFt), designated as HFt-MP-PASE-MIT, has shown excellent tumor distribution and extended serum half-life meriting further investigation for PC treatment. Thus, in this study, we used the same nano-formulation to test its cytotoxicity using both in vitro and in vivo assays. Interestingly, both encapsulated and free-MIT drugs demonstrated similar killing capabilities on PaCa44 cell line. Conversely, in vivo assessment in a subcutaneous PaCa44 tumor model of PC demonstrated a remarkable capability for encapsulated MIT to control tumor growth and improve mouse survival with a median survival rate of 65 vs. 33 days for loaded and free-MIT, respectively. Interestingly, throughout the course of mice treatment, MIT encapsulation did not present any adverse side effects as confirmed by histological analysis of various murine tissue organs and body mass weights. Our results are promising and pave the way to effective PC targeted chemotherapy using our HFt nanodelivery platforms.

Gastrointestinal tumors, including pancreatic and colorectal cancers, represent one of the greatest public health issues worldwide, leading to a million global deaths. Recent research demonstrated that the human heavy chain ferritin (HFt) can encapsulate different types of drugs in its cavity and can bind to its receptor, CD71, in several solid and hematological tumors, thus highlighting the potential use of ferritin for tumor-targeting therapies. Here, we describe the development and characterization of a novel nanomedicine based on the HFt that is named The-0504. In particular, this novel system is a nano-assembly comprising an engineered version of HFt that entraps about 80 molecules of a potent, wide-spectrum, non-camptothecin topoisomerase I inhibitor (Genz-644282). The-0504 can be produced by a standardized pre-industrial process as a pure and homogeneously formulated product with favourable lyophilization properties. The preliminary anticancer activity was evaluated in cultured cancer cells and in a mouse model of pancreatic cancer. Overall results reported here make The-0504 a candidate for further preclinical development against CD-71 expressing deadly tumors.

Iron oxide nanoparticles mineralized within the internal cavity of Ferritin protein cage are extremely appealing for the realization of multifunctional therapeutic and diagnostic agents for cancer treatment by drug delivery, magnetic fluid hyperthermia (MFH) and magnetic resonance imaging. Being the maximum mean size imposed by the internal diameter of the protein shell (ca. 8 nm) too small for the use of these systems in MFH, a valuable strategy for the improvement of the hyperthermic efficiency is increasing the magnetic anisotropy by doping the iron oxide with divalent Co ions. This strategy has been demonstrated to be highly efficient in the case of iron oxide nanoparticles mineralized in Human Ferritin (HFt). However, a deterioration of nanoparticles crystallinity and consequently a reduction of the hyperthermic efficiency were observed with increasing Co-doping. In this contribution, we compare two series of Co-doped iron oxide nanoparticles (Co-doping level up to 15%) mineralized into HFt and into Ferritin from the archaea Pirococcus Furiosus (PfFt), the protein structure of which differs for the nucleation sites, with the aim of increasing the crystalline quality of the inorganic cores for larger Co doping. Highly monodisperse nanoparticles of 6-7 nm were obtained in both series. The structural and magnetic characterization indicate that the PfFt series is less subjected to crystallinity deterioration with increasing Co content with respect to the HFt one. Such difference is reflected in the hyperthermic efficiency, which reaches the maximum value for different intermediate Co-doping (10% and 5% for PfFt and HFt, respectively), and goes to zero for further Co-doping increments.

Human transferrin receptor 1 (CD71) guarantees iron supply by endocytosis upon binding of iron-loaded transferrin and ferritin. Arenaviruses and the malaria parasite exploit CD71 for cell invasion and epitopes on CD71 for interaction with transferrin and pathogenic hosts were identified. Here, we provide the molecular basis of the CD71 ectodomain-human ferritin interaction by determining the 3.9 Å resolution single-particle cryo-electron microscopy structure of their complex and by validating our structural findings in a cellular context. The contact surfaces between the heavy-chain ferritin and CD71 largely overlap with arenaviruses and Plasmodium vivax binding regions in the apical part of the receptor ectodomain. Our data account for transferrin-independent binding of ferritin to CD71 and suggest that select pathogens may have adapted to enter cells by mimicking the ferritin access gate.

BackgroundThe possibility to combine Low Intensity UltraSound (LIUS) and Nanoparticles (NP) could represent a promising strategy for drugs delivery in tumors difficult to treat overcoming resistance to therapies. On one side the NP can carry drugs that specifically target the tumors on the other the LIUS can facilitate and direct the delivery to the tumor cells. In this study, we investigated whether Very Low Intensity UltraSound (VLIUS), at intensities lower than 120mW/cm(2), might constitute a novel strategy to improve delivery to tumor cells. Thus, in order to verify the efficacy of this novel modality in terms of increase selective uptake in tumoral cells and translate speedily in clinical practice, we investigated VLIUS in three different in vitro experimental tumor models and normal cells adopting three different therapeutic strategies.MethodsVLIUS at different intensities and exposure time were applied to tumor and normal cells to evaluate the efficiency in uptake of labeled human ferritin (HFt)-based NP, the delivery of NP complexed Firefly luciferase reported gene (lipoplex-LUC), and the tumor-killing of chemotherapeutic agent.ResultsSpecifically, we found that specific VLIUS intensity (120mW/cm(2)) increases tumor cell uptake of HFt-based NPs at specific concentration (0.5mg/ml). Similarly, VLIUS treatments increase significantly tumor cells delivery of lipoplex-LUC cargos. Furthermore, of interest, VLIUS increases tumor killing of chemotherapy drug trabectedin in a time dependent fashion. Noteworthy, VLIUS treatments are well tolerated in normal cells with not significant effects on cell survival, NPs delivery and drug-induced toxicity, suggesting a tumor specific fashion.ConclusionsOur data shed novel lights on the potential application of VLIUS for the design and development of novel therapeutic strategies aiming to efficiently deliver NP loaded cargos or anticancer drugs into more aggressive and unresponsive tumors niche.

Introduction Cancer remains still one of the major causes of death worldwide, therefore continuous improvements in tumor-fighting strategies are necessary. Targeting drugs directly to the tumour site, to overcome the systemic side effects, represents a great challenge. Nanoparticles have increasingly been used as drug delivery system showing intriguing therapeutic efficacies. Material and methods A genetically engineered nanocarrier based on human ferritin heavy chain (HFt) able to incorporate and deliver drugs was developed. These nanoparticles contain a short motif sequence (MP) cleavable by matrix metalloproteases between the HFt subunit and a masking sequence rich in proline (P), alanine (A) and serine (S): HFt-MP-PASE40. A topoisomerase I inhibitor was loaded into these nanocarriers (HFt-MP-PASE-Topo). Cell viability of different pancreatic cancer cell lines was evaluated in vitro . In vivo the therapeutic efficacy of HFt-MP-PASE-Topo was investigated on both a pancreatic cancer cell-line-derived xenograft and a patient-derived pancreatic cancer xenograft (PDX). Results and discussions In vitro studies showed a potent cytotoxic activity of HFt-MP-PASE-Topo with an IC50 that ranges between 0,005 µM to 0,05 µM. In vivo studies further demonstrated the therapeutic efficacy of HFt-MP-PASE-Topo in pancreatic cancer-bearing mice and in PDX model. In vivo treatments exhibited a robust decrease in tumour growth furthermore the animal overall survival significantly increased in HFt-MP-PASE-Topo treated mice. Conclusion Altogether, our results indicate that HFt-MP-PASE-Topo may constitute a promising tool in anticancer therapeutics.

A genetically engineered human ferritin heavy chain (HFt)-based construct has been recently shown by our group to efficiently entrap and deliver doxorubicin to cancer cells. This construct, named HFt-MP-PAS, contained a tumor-selective sequence (MP) responsive to proteolytic cleavage by tumor proteases (MMPs), located between each HFt subunit and an outer shielding polypeptide sequence rich in proline (P), serine (S) and alanine (A) residues (PAS). HFt-MP-PAS displayed excellent therapeutic efficacy in xenogenic pancreatic and head and neck cancer models in vivo, leading to a significant increase in overall animal survivals. Here we report a new construct obtained by the genetic insertion of two glutamate residues in the PAS sequence of HFt-MP-PAS. Such new construct, named HFt-MP-PASE, is characterized by improved performances as drug biodistribution in a xenogenic pancreatic cancer model in vivo. Moreover, HFt-MP-PASE efficiently encapsulates the anti-cancer drug mitoxantrone (MIT), and the resulting MIT-loaded nanoparticles proved to be more soluble and monodispersed than the HFt-MP-PAS counterparts. Importantly, in vitro MIT-loaded HFt-MP-PASE kills several cancer cell lines of different origin (colon, breast, sarcoma and pancreas) at least as efficiently as the free drug. Finally, our MIT loaded protein nanocages allowed in vivo an impressive incrementing of the drug accumulation in the tumor with respect to the free drug.