Evofosfamide

{{Infobox drug | drug_name = | INN = | type = | image = Evofosfamide.svg | image_class = skin-invert-image | width = | alt = | caption = | image2 = | width2 = | alt2 = | caption2 = | imageL = | widthL = | altL = | imageR = | widthR = | altR = | captionLR =

| IUPAC_name = <nowiki>2-bromo-N-[(2-bromoethylamino)-[(3-methyl-2-nitroimidazol-4-yl)methoxy]phosphoryl]ethanamine</nowiki> | C=9 | H=16 | Br=2 | N=5 | O=4 | P=1 | molecular_weight = | SMILES = CN1C(=CN=C1[N+](=O)[O-])COP(=O)(NCCBr)NCCBr | Jmol = | StdInChI = InChI=1S/C9H16Br2N5O4P/c1-15-8(6-12-9(15)16(17)18)7-20-21(19,13-4-2-10)14-5-3-11/h6H,2-5,7H2,1H3,(H2,13,14,19) | StdInChI_comment = | StdInChIKey = UGJWRPJDTDGERK-UHFFFAOYSA-N | density = | density_notes = | melting_point = | melting_high = | melting_notes = | boiling_point = | boiling_notes = | solubility = | sol_units = | specific_rotation = }}

'''Evofosfamide''', formerly known as '''TH-302''' is an investigational new drug that is being evaluated for the treatment of multiple tumor types, including pancreatic cancer,<ref name="Pourmorteza_2016">{{cite journal | vauthors = Pourmorteza M, Rahman ZU, Young M | title = Evofosfamide, a new horizon in the treatment of pancreatic cancer | journal = Anti-Cancer Drugs | volume = 27 | issue = 8 | pages = 723–5 | date = September 2016 | pmid = 27232101 | doi = 10.1097/CAD.0000000000000386 }}</ref> soft tissue sarcoma, and multiple myeloma, often in combination with other therapies. It is a hypoxia-activated prodrug designed to target and kill hypoxic cells within tumors. It functions by releasing the DNA crosslinking agent bromo-isophosphoramide mustard under low oxygen conditions, making it potentially effective against tumor regions where standard chemotherapy and radiation therapies are less effective due to hypoxia.<ref name="Hong_2018">{{cite journal | vauthors = Hong CR, Dickson BD, Jaiswal JK, Pruijn FB, Hunter FW, Hay MP, Hicks KO, Wilson WR | title = Cellular pharmacology of evofosfamide (TH-302): A critical re-evaluation of its bystander effects | journal = Biochemical Pharmacology | volume = 156 | issue = | pages = 265–280 | date = October 2018 | pmid = 30134191 | doi = 10.1016/j.bcp.2018.08.027 }}</ref><ref>{{cite journal | vauthors = Li Y, Zhao L, Li XF | title = The Hypoxia-Activated Prodrug TH-302: Exploiting Hypoxia in Cancer Therapy | journal = Frontiers in Pharmacology | volume = 12 | article-number = 636892 | date = 2021 | pmid = 33953675 | pmc = 8091515 | doi = 10.3389/fphar.2021.636892 | doi-access = free }}</ref><ref>{{Cite web |title=Evofosfamide |url=https://go.drugbank.com/drugs/DB06091 |access-date=2023-11-03 |website=go.drugbank.com |language=en}}</ref>

Commercialization has not been pursued due to the failure of several clinical trials.<ref name=":0" />

== Pharmacology==

Evofosfamide is a 2-nitroimidazole prodrug of the cytotoxin bromo-isophosphoramide mustard (Br-IPM).<ref name="Hong_2018" /> Evofosfamide is activated by a process that involves a 1-electron (1 e<sup>−</sup>) reduction mediated by ubiquitous cellular reductases, such as the NADPH cytochrome P450, to generate a radical anion prodrug: *A) In the presence of oxygen (normoxia) the radical anion prodrug reacts rapidly with oxygen to generate the original prodrug and superoxide. Therefore, evofosfamide is relatively inert under normal oxygen conditions, remaining intact as a prodrug. *B) When exposed to severe hypoxic conditions (< 0.5% O<sub>2</sub>; hypoxic zones in many tumors), however, the radical anion undergoes irreversible fragmentation, releasing the active drug Br-IPM and an azole derivative. The released cytotoxin Br-IPM alkylates DNA, inducing intrastrand and interstrand crosslinks.<ref>{{cite journal | vauthors = Weiss GJ, Infante JR, Chiorean EG, Borad MJ, Bendell JC, Molina JR, Tibes R, Ramanathan RK, Lewandowski K, Jones SF, Lacouture ME, Langmuir VK, Lee H, Kroll S, Burris HA | title = Phase 1 study of the safety, tolerability, and pharmacokinetics of TH-302, a hypoxia-activated prodrug, in patients with advanced solid malignancies | journal = Clinical Cancer Research | volume = 17 | issue = 9 | pages = 2997–3004 | date = May 2011 | pmid = 21415214 | doi = 10.1158/1078-0432.CCR-10-3425 | doi-access = free }}</ref>

Evofosfamide is largely inactive under normal oxygen levels. In areas of hypoxia, evofosfamide becomes activated and converts to an alkylating cytotoxic agent resulting in DNA cross-linking. This renders cells unable to replicable their DNA and divide, leading to apoptosis. This investigational therapeutic approach of targeting the cytotoxin to hypoxic zones in tumors may cause less broad systemic toxicity that is seen with untargeted cytotoxic chemotherapies.<ref>{{cite journal | title = TH-302 | vauthors = Pento JT | journal = Drugs of the Future |year = 2011 | volume = 36 | issue = 9 | pages = 663–667 | doi = 10.1358/dof.2011.036.09.1678337| s2cid = 258469551 }}</ref>

The activation of evofosfamide to the active drug Br-IPM and the mechanism of action (MOA) via cross-linking of DNA is shown schematically below:

800px|Activation of eofosfamide to the active drug Br-IPM, and mechanism of action via cross-linking of DNA

==Drug development history==

Phosphorodiamidate-based, DNA-crosslinking, bis-alkylator mustards have long been used successfully in cancer chemotherapy and include e.g. the prodrugs ifosfamide and cyclophosphamide. To demonstrate that known drugs of proven efficacy could serve as the basis of efficacious hypoxia-activated prodrugs, the 2-nitroimidizole HAP of the active phosphoramidate bis-alkylator derived from ifosfamide was synthesized. The resulting compound, TH-281, had a high HCR (hypoxia cytotoxicity ratio), a quantitative assessment of its hypoxia selectivity. Subsequent structure-activity relationship (SAR) studies showed that replacement of the chlorines in the alkylator portion of the prodrug with bromines improved potency about 10-fold. The resulting, final compound is evofosfamide (TH-302) which was developed by Threshold Pharmaceuticals Inc. .<ref>{{cite journal | vauthors = Duan JX, Jiao H, Kaizerman J, Stanton T, Evans JW, Lan L, Lorente G, Banica M, Jung D, Wang J, Ma H, Li X, Yang Z, Hoffman RM, Ammons WS, Hart CP, Matteucci M | title = Potent and highly selective hypoxia-activated achiral phosphoramidate mustards as anticancer drugs | journal = Journal of Medicinal Chemistry | volume = 51 | issue = 8 | pages = 2412–2420 | date = April 2008 | pmid = 18257544 | doi = 10.1021/jm701028q }}</ref> Threshold Pharmaceuticals Inc. applied for a patent on evofosfamide in 2006 which was granted in 2011.<ref>{{Cite patent| country = US | number = 8003625 |title=Phosphoramidate alkylator prodrugs|gdate=2011-08-23|inventor = Matteucci M, Duan JX, Jiao H, Kaizerman J |url=https://patents.google.com/patent/US8003625B2/ | assign = Immunogenesis Inc. }}</ref>

In 2012, Threshold signed a global license and co-development agreement for evofosfamide with Merck KGaA. Threshold was responsible for the development of evofosfamide in the soft tissue sarcoma indication in the United States. In all other cancer indications, Threshold and Merck KGaA developed evofosfamide together.<ref>{{Cite web |title=Threshold Pharmaceuticals and Merck KGaA Announce Global Agreement to Co-Develop and Commercialize Phase 3 Hypoxia-Targeted Drug TH-302 - Press release from 3 February 2012 |url=http://investor.thresholdpharm.com/releasedetail.cfm?ReleaseID=645974 |archive-url=https://web.archive.org/web/20141025130352/http://investor.thresholdpharm.com/releasedetail.cfm?ReleaseID=645974 |archive-date=25 October 2014 |access-date=25 October 2014}}</ref> After evofosfamide failed to improve longevity in patients in phase three clinical trials, Merck abandoned attempts to commercialize evofosfamide in 2015.<ref name=":0">{{Cite web |date=2015-12-09 |title=Merck abandons evofosfamide as two trials fail - PMLiVE |url=https://pmlive.com/pharma_news/merck_abandons_evofosfamide_as_two_trials_fail_883775 |access-date=2025-03-09 |website=pmlive.com |language=en-GB}}</ref>

== Chemistry == === Synthesis ===

Evofosfamide synthesis involves several steps, starting with the preparation of 2-nitroimidazole derivatives:

# '''Preparation of 2-nitroimidazole''': This is the key bioreductive group used in the synthesis. # '''Formation of the prodrug''': The 2-nitroimidazole is linked to a brominated derivative of isophosphoramide mustard. # '''Activation under hypoxic conditions''': In low oxygen environments, typical of solid tumors, the prodrug is activated to release the cytotoxic agent.

The activation under hypoxic conditions allows evofosfamide to target hypoxic tumor cells selectively, making it a candidate in for cancer treatment.<ref>{{Cite web |url=http://www.cphi.cn/news/show-121474.html |title=CPhI.cn: Synthetic routes to explore anti-pancreatic cancer drug Evofosfamide, 22 Jan 2015 |access-date=14 February 2015 |archive-date=14 February 2015 |archive-url=https://web.archive.org/web/20150214222335/http://www.cphi.cn/news/show-121474.html }}</ref><ref>{{Cite journal | vauthors = O'Connor LJ, Cazares-Körner C, Saha J, Evans CN, Stratford MR, Hammond EM, Conway SJ |date=2015-08-13 |title=Efficient synthesis of 2-nitroimidazole derivatives and the bioreductive clinical candidate Evofosfamide (TH-302) |url=https://pubs.rsc.org/en/content/articlelanding/2015/qo/c5qo00211g |journal=Organic Chemistry Frontiers |language=en |volume=2 |issue=9 |pages=1026–1029 |doi=10.1039/C5QO00211G |issn=2052-4129|url-access=subscription }}</ref><ref>{{Cite web |title=Evofosfamide |url=https://go.drugbank.com/drugs/DB06091 |access-date=2024-09-14 |website=go.drugbank.com |language=en}}</ref>

==Clinical trials==

===Overview and results===

Evofosfamide (TH-302) was evaluated in clinical studies as a monotherapy and in combination with chemotherapy agents and other targeted cancer drugs. The indications were a broad spectrum of solid tumor types and blood cancers.

Evofosfamide clinical trials (as of 16 March 2025):<ref>{{cite web | title = Search results for: Evofosfamide| url = https://clinicaltrials.gov/search?intr=Evofosfamide | work = ClinicalTrials.gov }}</ref>

{| class="wikitable mw-collapsible mw-collapsed" |+ style="white-space: nowrap;" | Clinical Trials of TH-302 (Evofosfamide) ! NCT ID !! Title !! Phase !! Study Status |- | {{ClinicalTrialsGov|NCT0074337}} || Dose-Escalation Study of TH-302 || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0114445}} || Study of the Safety and Efficacy of TH-302 || PHASE2 || COMPLETED |- | {{ClinicalTrialsGov|NCT0114991}} || Study of Hypoxia-Activated Prodrug TH-302 to Treat Advanced Leukemias || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0138182}} || Dose-Escalation Study of TH-302 in Combination With Sunitinib || PHASE1 || UNKNOWN |- | {{ClinicalTrialsGov|NCT0140361}} || Safety and Efficacy Study of TH-302 CNS Penetration in Recurrent High Grade Astrocytoma || PHASE2 || COMPLETED |- | {{ClinicalTrialsGov|NCT0144008}} || A Trial of TH-302 in Combination With Doxorubicin || PHASE2 || COMPLETED |- | {{ClinicalTrialsGov|NCT0148504}} || Dose Escalation Study of Pazopanib Plus TH-302 || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0149744}} || Sorafenib Tosylate and Hypoxia-Activated Prodrug TH-302 in Treating Advanced Kidney or Liver Cancer || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0152287}} || Open-label Study of TH-302 and Dexamethasone || PHASE1 || UNKNOWN |- | {{ClinicalTrialsGov|NCT0172194}} || TH-302 Plus Doxorubicin Delivered by Trans-Arterial Chemoembolization (TACE) || PHASE1 || UNKNOWN |- | {{ClinicalTrialsGov|NCT0174697}} || Clinical Trial Testing TH-302 in Combination With Gemcitabine || PHASE3 || COMPLETED |- | {{ClinicalTrialsGov|NCT0183354}} || A Japanese Phase 1 Trial of TH-302 || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0186459}} || A Phase 2 Biomarker-Enriched Study of TH-302 in Advanced Melanoma || PHASE2 || TERMINATED |- | {{ClinicalTrialsGov|NCT0202022}} || A Cardiac Safety Study of TH-302 || PHASE1 || UNKNOWN |- | {{ClinicalTrialsGov|NCT0204750}} || Phase I TH-302 Plus Gemcitabine Plus Nab-Paclitaxel || PHASE1 || TERMINATED |- | {{ClinicalTrialsGov|NCT0207629}} || A Phase 1 TH-302 Mass Balance Trial || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0209396}} || Study of TH-302 or Placebo in Combination With Pemetrexed || PHASE2 || TERMINATED |- | {{ClinicalTrialsGov|NCT0225511}} || A Japanese Trial of TH-302 in Soft Tissue Sarcoma || PHASE2 || TERMINATED |- | {{ClinicalTrialsGov|NCT0234237}} || TH-302 in Combination With Bevacizumab for Glioblastoma || PHASE2 || COMPLETED |- | {{ClinicalTrialsGov|NCT0240206}} || A Study to Assess the Safety and Efficacy of TH-302 and Sunitinib in Neuroendocrine Pancreatic Tumours || PHASE1 || COMPLETED |- | {{ClinicalTrialsGov|NCT0243369}} || Study of TH-302 Monotherapy as Second-line Treatment in Biliary Tract Cancer || PHASE2 || COMPLETED |- | {{ClinicalTrialsGov|NCT0249689}} || A Study of Hypoxia Imaging in Pancreatic Cancer Patients Being Treated With Gemcitabine and TH-302 || NA || WITHDRAWN |- | {{ClinicalTrialsGov|NCT0259868}} || Testing TH-302, in Combination With Preoperative Chemoradiotherapy, in Esophageal Cancer || PHASE1 || WITHDRAWN |- | {{ClinicalTrialsGov|NCT0271256}} || SARC021C: A Continuation Study of TH-CR-406/SARC021 || NA || NO_LONGER_AVAILABLE |- | {{ClinicalTrialsGov|NCT0309816}} || Immunotherapy Study of Evofosfamide in Combination With Ipilimumab || PHASE1 || UNKNOWN |- | {{ClinicalTrialsGov|NCT0678255}} || A Study of Evofosfamide in Combination with Zalifrelimab and Balstilimab || PHASE1 || RECRUITING |- | {{ClinicalTrialsGov|NCT0683672}} || Clinical Trial to Test Efficacy of Targeting Hypoxia Combined With ARSI After First-line ARSI Therapy for Castrate Resistant Prostate Cancer || PHASE2 || NOT_YET_RECR |}

===Soft tissue sarcoma===

Evofosfamide was tested in combination with doxorubicin in patients with advanced soft tissue sarcoma. The study TH-CR-403 was a single arm trial investigating evofosfamide in combination with doxorubicin.<ref>{{cite journal | vauthors = Chawla SP, Cranmer LD, Van Tine BA, Reed DR, Okuno SH, Butrynski JE, Adkins DR, Hendifar AE, Kroll S, Ganjoo KN | title = Phase II study of the safety and antitumor activity of the hypoxia-activated prodrug TH-302 in combination with doxorubicin in patients with advanced soft tissue sarcoma | journal = Journal of Clinical Oncology | volume = 32 | issue = 29 | pages = 3299–3306 | date = October 2014 | pmid = 25185097 | pmc = 4588714 | doi = 10.1200/JCO.2013.54.3660 }}</ref> Evofosfamide was further tested in the Phase 3 clinical trial TH-CR-406/SARC021 with results published in 2017 indicating no improvement in patient mortality rates.<ref>{{cite journal | vauthors = Tap WD, Papai Z, Van Tine BA, Attia S, Ganjoo KN, Jones RL, Schuetze S, Reed D, Chawla SP, Riedel RF, Krarup-Hansen A, Toulmonde M, Ray-Coquard I, Hohenberger P, Grignani G, Cranmer LD, Okuno S, Agulnik M, Read W, Ryan CW, Alcindor T, Del Muro XF, Budd GT, Tawbi H, Pearce T, Kroll S, Reinke DK, Schöffski P | title = Doxorubicin plus evofosfamide versus doxorubicin alone in locally advanced, unresectable or metastatic soft-tissue sarcoma (TH CR-406/SARC021): an international, multicentre, open-label, randomised phase 3 trial | journal = The Lancet. Oncology | volume = 18 | issue = 8 | pages = 1089–1103 | date = August 2017 | pmid = 28651927 | pmc = 7771354 | doi = 10.1016/S1470-2045(17)30381-9 }}</ref>

===Metastatic pancreatic cancer===

Evofosfamide was studied in combination with gemcitabine in patients with metastatic pancreatic cancer. The study TH-CR-404 compared gemcitabine with gemcitabine plus evofosfamide.<ref>{{cite journal | vauthors = Borad MJ, Reddy SG, Bahary N, Uronis HE, Sigal D, Cohn AL, Schelman WR, Stephenson J, Chiorean EG, Rosen PJ, Ulrich B, Dragovich T, Del Prete SA, Rarick M, Eng C, Kroll S, Ryan DP | title = Randomized Phase II Trial of Gemcitabine Plus TH-302 Versus Gemcitabine in Patients With Advanced Pancreatic Cancer | journal = Journal of Clinical Oncology | volume = 33 | issue = 13 | pages = 1475–1481 | date = May 2015 | pmid = 25512461 | pmc = 4881365 | doi = 10.1200/JCO.2014.55.7504 }}</ref> The study showed comparable efficacy profiles for evofosfamide and nab-paclitaxel when combined with gemcitabine;<ref>{{cite journal | vauthors = Von Hoff DD, Ervin T, Arena FP, Chiorean EG, Infante J, Moore M, Seay T, Tjulandin SA, Ma WW, Saleh MN, Harris M, Reni M, Dowden S, Laheru D, Bahary N, Ramanathan RK, Tabernero J, Hidalgo M, Goldstein D, Van Cutsem E, Wei X, Iglesias J, Renschler MF | title = Increased survival in pancreatic cancer with nab-paclitaxel plus gemcitabine | journal = The New England Journal of Medicine | volume = 369 | issue = 18 | pages = 1691–1703 | date = October 2013 | pmid = 24131140 | pmc = 4631139 | doi = 10.1056/NEJMoa1304369 }}</ref> however, the hematologic toxicity was higher for patients given evofosfamide vs. nab-paclitaxel.

In the Phase 3 MAESTRO study, patients with previously untreated, locally advanced unresectable or metastatic pancreatic adenocarcinoma treated with evofosfamide in combination with gemcitabine did ''not'' demonstrate a statistically significant improvement in overall survival.<ref>{{Cite journal | vauthors = Van Cutsem E, Lenz HJ, Furuse J, Tabernero J, Heinemann V, Ioka T, Bazin I, Ueno M, Csoszi T, Wasan H, Melichar B |date=2016-05-20 |title=MAESTRO: A randomized, double-blind phase III study of evofosfamide (Evo) in combination with gemcitabine (Gem) in previously untreated patients (pts) with metastatic or locally advanced unresectable pancreatic ductal adenocarcinoma (PDAC). |url=http://ascopubs.org/doi/10.1200/JCO.2016.34.15_suppl.4007 |journal=Journal of Clinical Oncology |language=en |volume=34 |issue=15_suppl |page=4007 |doi=10.1200/JCO.2016.34.15_suppl.4007 |issn=0732-183X|url-access=subscription }}</ref>

=== Nasopharyngeal Carcinoma === Oxygen deficient conditions are linked to tumor progression throughout the body and poses an issue in cancer treatments such as chemotherapy and radiation.<ref name = "Li_2021">{{cite journal | vauthors = Li Y, Zhao L, Li XF | title = Targeting Hypoxia: Hypoxia-Activated Prodrugs in Cancer Therapy | journal = Frontiers in Oncology | volume = 11 | article-number = 700407 | date = 2021-07-29 | pmid = 34395270 | pmc = 8358929 | doi = 10.3389/fonc.2021.700407 | doi-access = free }}</ref> Hypoxia-activated prodrugs (HAPs) function in hypoxic conditions and inhibit the growth of tumor cells.<ref name = "Li_2021" /> Evofosfamide is a HAP that targets tumor progression in nasopharyngeal carcinoma (NPC) tissues by inhibiting the overexpression of hypoxia-inducible factor-1α (HIF-1α).<ref name = "Huang_2018">{{cite journal | vauthors = Huang Y, Tian Y, Zhao Y, Xue C, Zhan J, Liu L, He X, Zhang L | title = Efficacy of the hypoxia-activated prodrug evofosfamide (TH-302) in nasopharyngeal carcinoma in vitro and in vivo | journal = Cancer Communications | volume = 38 | issue = 1 | date = May 2018 | page = 15 | pmid = 29764490 | pmc = 5993153 | doi = 10.1186/s40880-018-0285-0 | doi-access = free }}</ref>

In this study , the efficacy of Evofosfamide along with cisplastin (DDP) in blocking cell progression was measured. "The combination of evofosfamide with DDP had a synergistic effect on cytotoxicity in the NPC cell lines by combination index values assessment. Cell cycle G2 phase was arrested after treated with 0.05 μmol/L evofosfamide under hypoxia. Histone H2AX phosphorylation (γH2AX) (a marker of DNA damage) expression increased while HIF-1α expression suppressed after evofosfamide treatment under hypoxic conditions".<ref name = "Huang_2018" /> These findings allow for evidence for Evofosfamide to be pushed towards clinical trials to further investigate the potential to be developed as an FDA approved anticancer drug.{{citation needed|date=May 2025}}

== References == {{Reflist|3}}

Category:Experimental cancer drugs Category:Prodrugs Category:Alkylating antineoplastic agents Category:Drugs developed by Merck Category:Nitrogen mustards Category:Phosphorodiamidates Category:Nitroimidazoles Category:Organobromides Category:Bromoethyl compounds

Evofosfamide

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