Filed Pursuant to Rule 424(b)(5)​

PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights information contained elsewhere or incorporated by reference in this prospectus supplement and the accompanying prospectus. This summary does not contain all of the information that you should consider before deciding to invest in our common stock. You should read this entire prospectus supplement and the accompanying prospectus carefully, including the “Risk Factors” section contained in this prospectus supplement, our consolidated financial statements and the related notes thereto and the other documents incorporated by reference in this prospectus supplement and the accompanying prospectus.

Overview

We are a biopharmaceutical company dedicated to the development and commercialization of novel, mechanism-targeted drugs to treat human cancers and other serious diseases. Our strategy is to build a diversified biopharmaceutical business in hematology and oncology based on a development pipeline of novel drug candidates.

Our clinical development priorities are focused on sapacitabine, an orally available, cell cycle modulating nucleoside analog and the cyclin dependent kinase (“CDK”) inhibitor program.

Sapacitabine is being evaluated in the SEAMLESS Phase 3 study, which completed enrollment in December 2014 and is being conducted under a Special Protocol Assessment (“SPA”) agreement with the U.S. Food and Drug Administration (“FDA”) for the front-line treatment of acute myeloid leukemia (“AML”) in the elderly. In December 2014, the study’s Data Safety Monitoring Board, or DSMB, conducted a planned interim analysis for futility after 247 events, or patient deaths, and the final safety review of 470 randomized patients. The DSMB found no safety concerns. However, the planned futility boundary has been crossed and the DSMB determined that, based on available interim data, it would be unlikely for the study to reach statistically significant improvement in survival. The DSMB saw no reasons why patients should discontinue treatment on their assigned arm and recommended that recruited patients stay on treatment.

The interim analysis for futility performed in December 2014 was primarily driven by the events within the first 6 months of patients entering into the trial. Of 247 events in SEAMLESS, 173 (70%) have occurred in the first 6 months. This means that the survival curves beyond 6 months are poorly estimated at the time of the December analysis. Furthermore, follow up of European patients at December 2014 is significantly shorter than that of U.S. patients as the study opened for European accrual in April 2014. It is important to have complete follow up of all patients to ensure that a potential treatment effect beyond 6 months is not missed.

In accordance with the DSMB’s recommendations, we continue to follow-up patients as per the study protocol. The required number of events has been reached and we are conducting data cleaning and validation operations prior to determining that the study data base can be locked. Study data will then be transferred to our independent statistical analysis vendor. When final analysis becomes available, we will report outcomes for the primary and secondary endpoints and determination of submissibility of the SEAMLESS data set to regulatory authorities in Europe and the United States. The procedures to be followed prior to reporting topline data and determination of submissibility to regulatory authorities may take several months.

In parallel to the follow-up of enrolled patients, we have submitted, and received validation of, a Pediatric Investigation Plan, or PIP, to the European Medicines Agency (“EMA”). The EMA requires sponsors to agree to a PIP before a marketing authorization application, or MAA, can be accepted, and because the lead times can be long, we submitted the PIP ahead of any MAA submission.

Sapacitabine is also being explored in other indications, including myelodysplastic syndromes (“MDS”) and in our DNA damage response program in solid tumors in combination with our own drug candidate, seliciclib. Sapacitabine has been evaluated in over 1,000 patients with various cancers. The FDA and the EMA have designated sapacitabine as an orphan drug for the treatment of both AML and MDS.

In our DNA damage response program, durable antitumor activity was reported at an oral presentation at the 2016 American Society of Clinical Oncology Annual Meeting with a combination of sapacitabine and seliciclib, our CDK2/9 inhibitor, in heavily pretreated patients with breast, ovarian and

pancreatic cancers who tested positive for BRCA mutations. A disease control rate of 35.6% was observed, with ongoing responding patients achieving treatment durations exceeding 1 and 4.7 years, respectively.

Seliciclib is our lead CDK inhibitor. CDKs are involved in cancer cell growth, survival, metastatic spread and DNA damage repair and are central to the process of cell division and cell cycle control. Seliciclib is an oral, highly selective inhibitor of CDK enzymes that has been evaluated in over 450 patients with various cancers, including a Phase 2b randomized study in third-line non-small cell lung cancer (“NSCLC”), and nasopharyngeal cancer (“NPC”), and has shown signs of anticancer activity. We have retained worldwide rights to commercialize seliciclib. Seliciclib is also being evaluated in Investigator Sponsored Trials, or ISTs, to treat Cushing’s disease and rheumatoid arthritis, or RA and in a licensing and supply agreement to treat cystic fibrosis.

Our second generation CDK inhibitor, CYC065, is a highly selective inhibitor of CDKs targeting CDK2/9 enzymes with potential utility in both hematological malignancies and solid tumors. CYC065 has increased anti-proliferative potency and improved pharmaceutical properties compared to seliciclib. CYC065 is in an on-going first-in-human, Phase 1 trial to assess its safety, tolerability, pharmacokinetics and pharmacodynamics in advanced cancer patients. CYC065 was selected from our drug discovery program in Dundee, Scotland.

In addition to these development programs, in our polo-like kinase (“PLK”) inhibitor program, we have discovered CYC140 and other potent and selective small molecule inhibitors of PLK1, a kinase that is active during cell division, which targets the mitotic phase of the cell cycle. PLK1 was discovered by Professor David Glover, our Chief Scientist. We are progressing CYC140 through Investigational New Drug (“IND”) directed preclinical development with the support of government funding.

We currently retains virtually all marketing rights worldwide to the compounds associated with our drug programs.

Substantially all of our efforts to date have been devoted to performing research and development, conducting clinical trials, developing and acquiring intellectual property, raising capital and recruiting and training personnel.

Recent Developments

Entry into At Market Issuance Sales Agreement with FBR Capital Markets & Co.

On June 23, 2016, we entered into the At Market Issuance Sales Agreement, which we refer to as the sales agreement, with FBR, under which we may, from time to time, sell shares of common stock through FBR. To date, we have sold 766,149 shares of common stock under the sales agreement for net proceeds to the Company of approximately $3.9 million pursuant to a prospectus supplement dated as of June 23, 2016. We are filing this prospectus supplement to sell, from time to time, up to an additional $4.0 million shares of common stock. We are not obligated to make any sales of common stock under the sales agreement.

Corporate Information

Our corporate headquarters are located at 200 Connell Drive, Suite 1500, Berkeley Heights, New Jersey, 07922, and our telephone number is (908) 517-7330. This is also where our medical and regulatory functions are located. Our research facility is located in Dundee, Scotland, which is also the center of our translational work and development programs. Our Internet address is http://www.cyclacel.com. The information on our website is not a part of, and should not be construed as being incorporated by reference into, this prospectus supplement or the accompanying prospectus.

THE OFFERING

Shares of our common stock having an aggregate offering price of up to $4.0 million. In no event will we sell securities with a value exceeding more than one-third of our “public float” (the market value of our common stock and any other equity securities that we may issue in the future that are held by non-affiliates) in any 12-calendar month period.

Up to 4,418,514 shares, assuming sales of 645,161 shares of our common stock in this offering at an offering price of  $6.20 per share, which was the last reported sale price of our common stock on the NASDAQ Capital Market on August 29, 2016. The actual number of shares issued will vary depending on the sales price under this offering.

“At the market offering” that may be made from time to time on the NASDAQ Capital Market or other market for our common stock in the United States through our agent, FBR Capital Markets & Co. See the section entitled “Plan of Distribution” on page S-9 of this prospectus supplement.

We intend to use the net proceeds from this offering, if any, for our operations, for working capital and other general corporate purposes. See the section entitled “Use of Proceeds” on page S-7 of this prospectus supplement.

See the “Risk Factors” section in this prospectus supplement and the accompanying prospectus and the other information included in, or incorporated by reference into, this prospectus supplement for a discussion of certain factors you should carefully consider before deciding to invest in shares of our common stock.

CYCC

The number of common stock to be outstanding immediately after this offering as shown above is based on 3,773,353 shares of common stock outstanding as of August 29, 2016, but exclude the following as of such date:

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393,723 shares of common stock issuable upon the exercise of outstanding options at a weighted-average exercise price of  $31.52 per share;

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472 shares of common stock available for issuance under our 2015 Equity Incentive Plan; and

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1,698 shares of common stock, subject to adjustment, that are issuable upon the conversion of 335,273 shares of convertible preferred stock that are issued and outstanding.

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All ref erences in this prospectus to number of shares of common stock, price per share and weighted average shares of common stock have been adjusted to reflect the Reverse Stock Split on a retroactive basis for all periods presented, unless otherwise noted.

PROSPECTUS SUMMARY

The following is a summary of what we believe to be the most important aspects of our business and the offering of our securities under this prospectus. We urge you to read this entire prospectus, including the more detailed consolidated financial statements, notes to the consolidated financial statements and other information incorporated by reference from our other filings with the SEC or included in any applicable prospectus supplement. Investing in our securities involves risks. Therefore, carefully consider the risk factors on page 14 of this prospectus and in any prospectus supplements and in our most recent annual and quarterly filings with the SEC, as well as other information in this prospectus and any prospectus supplements and the documents incorporated by reference herein or therein, before purchasing our securities. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities.

Our Business

General

We are a biopharmaceutical company dedicated to the development and commercialization of novel, mechanism-targeted drugs to treat human cancers and other serious diseases. Our strategy is to build a diversified biopharmaceutical business in hematology and oncology based on a development pipeline of novel drug candidates.

Drug Candidates

The cell cycle, the biological process by which cells propagate and divide, lies at the heart of cancer. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates its DNA and divides. This process also includes mechanisms to ensure errors are corrected, and if not, the cells commit suicide or apoptose. In cancer, as a result of genetic mutations, this regulatory process malfunctions, resulting in uncontrolled cell proliferation.

We have generated several families of anticancer drugs that act on the cell cycle including sapacitabine, seliciclib and CYC065. We believe that these drug candidates are differentiated in that they are orally-available and interact with unique target profiles and mechanisms and have the potential to treat multiple cancer indications.

Our lead candidate, sapacitabine, is a novel, orally-available nucleoside analog. A number of nucleoside drugs, such as gemcitabine and cytarabine, also known as Ara-C, both generic drugs, are in wide use as conventional chemotherapies. Both sapacitabine and its major metabolite, CNDAC, have demonstrated potent anti-tumor activity in both blood and solid tumors in preclinical studies. In a liver metastatic mouse model, sapacitabine was shown to be superior to gemcitabine and fluorouracil, or 5-FU, two widely used nucleoside analogs, in delaying the onset and growth of liver metastasis. We hold the worldwide rights to commercialize sapacitabine, except for Japan, for which Daiichi Sankyo Co., Ltd., or Daiichi Sankyo, has a right of first negotiation.

The U.S. Food and Drug Administration, or FDA, and the European Medicines Agency, or EMA, have designated sapacitabine as an orphan drug for the treatment of both Acute Myeloid Leukemia, or AML, and Myelodysplastic Syndromes, or MDS.

We are currently evaluating sapacitabine in a Phase 3 study being conducted under a Special Protocol Assessment, or SPA, with the FDA for the front-line treatment of AML in the elderly. We are also exploring sapacitabine in a Phase 2 study for MDS and in a Phase 1/2 study in solid tumors in combination with seliciclib, another of our drug candidates. Sapacitabine has been evaluated in approximately 1,000 patients to date.

In our second development program, we are evaluating cyclin dependent kinase, or CDK, inhibitors. CDKs are involved in cancer cell growth, survival, metastatic spread and DNA damage repair. Seliciclib, our lead CDK inhibitor, is an oral, highly selective inhibitor of CDK2/9 enzymes that are central to the

process of cell division and cell cycle control. To date, seliciclib has been evaluated in over 450 patients with various cancers, including non-small cell lung cancer, or NSCLC, and nasopharyngeal cancer, or NPC, and has shown signs of anticancer activity. We have retained worldwide rights to commercialize seliciclib.

Seliciclib has completed a Phase 2b randomized study in third-line NSCLC and is currently undergoing a study in solid tumors in combination with our own drug candidate, sapacitabine. Seliciclib is also being evaluated in Investigator Sponsored Trials, or ISTs, to treat Cushing’s disease and rheumatoid arthritis, and in a license and supply agreement for the treatment of cystic fibrosis.

Our second generation CDK inhibitor, CYC065, is a highly selective inhibitor of CDKs targeting CDK2/9 enzymes with potential utility in both hematological malignancies and solid tumors. CYC065 has increased anti-proliferative potency and improved pharmaceutical properties compared to seliciclib. CYC065 is in an on-going first-in-human, Phase 1 trial to assess its safety, tolerability, pharmacokinetics and pharmacodynamics in advanced cancer patients. CYC065 was selected from the Company’s discovery program in Dundee, Scotland and its development was supported in part by a $1.9 million grant from the Biomedical Catalyst of the United Kingdom government.

In addition to these development programs, in our polo-like kinase, or PLK, inhibitor program, we have discovered CYC140 and other potent and selective small molecule inhibitors of PLK1, a kinase that is active during cell division and which targets the mitotic phase of the cell cycle. PLK was discovered by Professor David Glover, our Chief Scientist. We have received a grant award of approximately $3.5 million from the Biomedical Catalyst of the United Kingdom government to complete IND-directed preclinical development of CYC140.

We currently retain virtually all marketing rights worldwide to the compounds associated with our drug programs. To optimize our commercial return, we intend to enter into selected partnering arrangements.

Clinical programs

Our pipeline and expertise in cell cycle biology

Our core area of expertise is in cell cycle biology and we focus primarily on the development of orally-available anticancer agents that target the cell cycle with the aim of slowing the progression or shrinking the size of tumors, and enhancing the quality of life and improving survival rates of cancer patients.

We have retained rights to commercialize our clinical development candidates and our business strategy is to enter into selective partnership arrangements with these programs.

Oncology Development Programs

We have generated several families of anticancer drugs that act on the cell cycle, including nucleoside analogs, CDK inhibitors, PLK inhibitors and Aurora Kinase/vascular endothelial growth factor receptor, or AK/VEGFR inhibitors. In our development programs, we have been an early adopter of biomarker analysis to help evaluate whether our drug candidates are having their intended effect through their assumed mechanisms at different doses and schedules. Biomarkers are proteins or other biological substances or effects whose presence in patient samples can serve as an indicator or marker of diseases, or may highlight patients more likely to respond to a particular treatment. Biomarker data from early clinical trials may also enable us to design subsequent trials more efficiently and to monitor patient compliance with trial protocols. For example, we reported that sapacitabine efficacy is enhanced in tumor cells that are defective in homologous recombination DNA repair and that sapacitabine treatment increased a DNA damage marker in patient samples. We believe that in the longer term biomarkers may allow the selection of patients more likely to respond to our drugs in clinical trials and increase the benefit to patients.

Although a number of pharmaceutical and biotechnology companies are currently attempting to develop nucleoside analogs, CDK inhibitors and PLK inhibitors, we believe that our drug candidates are differentiated in that they are orally-available and demonstrate unique target profiles and mechanisms. For example, we believe that our sapacitabine is the only orally-available nucleoside analog presently being tested in a Phase 3 trial in previously untreated AML and in Phase 2 for high risk MDS.

Research and Development Pipeline

The following table summarizes our currently active clinical and preclinical programs.

Market opportunity in hematology

Cancer remains a major life-threatening disease in the United States with approximately 3.2 million people afflicted by cancer and approximately 1.4 million new cases of cancer diagnosed every year.

AML is a cancer of the blood cells that progresses rapidly and if not treated, could be fatal within a few months. AML is generally a disease of older people and is uncommon before the age of 40. The average age of a patient with AML is about 67 years. According to The Surveillance, Epidemiology, and End Results, or SEER, program of the National Cancer Institute, or NCI, the incidence rate of AML is approximately 20,000 in the United States. It is estimated that European incidence is approximately 22,000. A review of The University of Texas MD Anderson Cancer Center’s historical experience with front-line intensive induction chemotherapy for AML patients aged 70 years or older demonstrated that while 45% achieved a complete remission, median overall survival was only 4.6 months and was associated with a 4-week death rate of 26% and an 8-week death rate of 36%.

MDS is a family of clonal myeloid neoplasms, or malignancies of the blood, caused by the failure of blood cells in the bone marrow to develop into mature cells. Patients with MDS typically suffer from bone marrow failure and cytopenias, or reduced counts of platelets, red and white blood cells. The exact incidence and prevalence of MDS are unknown because it can go undiagnosed and a national survey canvassing both hospitals and office practitioners has not been completed. Some estimates place MDS incidence at 15,000 to 20,000 new cases each year in the United States alone with some authors estimating incidence as high as 46,000. Literature suggests that there is a rising incidence of MDS as the age of the population increases with the majority of patients aged above 60 years. Patients currently receive hypomethylating agents as first-line treatment. There is no approved therapy for second-line treatment.

Sapacitabine

Sapacitabine, previously known as CYC682, is an orally-available nucleoside analog. Both sapacitabine and CNDAC, its major metabolite, have demonstrated potent anti-tumor activity in preclinical studies. Sapacitabine is an orally-available prodrug of CNDAC, which is a novel nucleoside analog, or a compound with a structure similar to a nucleoside. A prodrug is a compound that has a therapeutic effect after it is metabolized within the body. CNDAC has a significantly longer residence time in the blood when it is produced in the body through metabolism of sapacitabine than when it is given directly. Sapacitabine acts through a novel mechanism whereby the compound interferes with DNA synthesis through the incorporation of CNDAC into DNA during replication or repair, triggering a beta-elimination reaction and leading to the formation of single-strand DNA breaks, or SSBs. During subsequent rounds of replication, SSBs are converted to double-strand breaks, or DSBs; these can be repaired by the homologous recombination repair, or HRR, pathway, or, if unrepaired, result in cell death.

We are currently exploring sapacitabine in both hematological cancers and solid tumors. Approximately 1,000 patients have received sapacitabine in Phase 1, 2 and 3 studies.

Hematological Cancers

SEAMLESS, randomized Phase 3, pivotal trial of sapacitabine in elderly patients with AML

The SEAMLESS study is being conducted under an SPA agreement that Cyclacel reached with the FDA.

The study is chaired by Hagop M. Kantarjian, M.D., Chairman and Professor, Department of Leukemia, The University of Texas MD Anderson Cancer Center. SEAMLESS is a multicenter, randomized, Phase 3 study of sapacitabine as a front-line treatment in approximately 485 elderly patients aged 70 years or older with newly diagnosed AML who are not candidates for or have refused intensive induction chemotherapy. In SEAMLESS an investigational arm of oral sapacitabine administered in alternating cycles with intravenous decitabine is compared with a control arm of intravenous decitabine administered alone. The primary efficacy endpoint is overall survival. SEAMLESS completed enrollment in December 2014 with approximately 110 centers participating from the United States and Europe. Also in December 2014, the Data Safety Monitoring Board, or DSMB, conducted a planned interim analysis for futility after 247 events, or patient deaths, and the final safety review of 470 randomized patients. The DSMB found no safety concerns. However, the planned futility boundary has been crossed and the DSMB determined that, based on available interim data, it would be unlikely for the study to reach statistically significant improvement in survival. The DSMB saw no reasons why patients should discontinue treatment on their assigned arm and recommended that recruited patients stay on treatment.

The interim analysis for futility performed in December 2014 was primarily driven by the events within the first 6 months of patients entering into the trial. Of 247 events in SEAMLESS, 173 (70%) have occurred in the first 6 months. This means that the survival curves beyond 6 months are poorly estimated at the time of the analysis. Furthermore, follow up of European patients at December 2014 is significantly shorter than that of U.S. patients as the study opened for European accrual in April 2014. It is important to have complete follow up of all patients to ensure that a potential treatment effect beyond 6 months is not missed.

In accordance with the DSMB’s recommendations, we continue to follow-up patients as per the study protocol until the prespecified 424 events have been observed. This is estimated to occur in the first half of 2016. Approximately 4% of the prespecified events remain to be observed as of March 25, 2016.

In parallel to the follow-up of enrolled patients we have submitted, and have received validation of, a Pediatric Investigation Plan, or PIP, to the EMA. The EMA requires sponsors to agree to a PIP before a marketing authorization application, or MAA, can be accepted, and because the lead times can be long, we submitted the PIP ahead of any MAA submission. Depending on the final data, we may meet with regulatory authorities in Europe and the United States to discuss registration submissions for sapacitabine for the AML indication.

Pilot/Lead-in study of sapacitabine in elderly patients with AML

Results from a single-arm, multicenter, Phase 1/2 clinical trial examining the safety and efficacy of oral sapacitabine administered sequentially with intravenous decitabine, the same regimen as in the investigational arm of SEAMLESS, were reported during a poster session at the 2012 American Society of Hematology, or ASH, Annual Meeting. Forty-six patients were treated with alternating cycles of sapacitabine and decitabine. Median age was 77 years (range 70-90). Thirty-three patients (72%) were 75 years or older. Median overall survival was 238 days, or approximately 8 months. The number of patients still alive at 3 months was 38 (83%), at 6 months 30 (65%), at 12 months 16 (35%) and at 18 months 12 (26%). Sixteen patients (35%) survived 1 year or longer. Among 33 patients who were 75 years or older, median overall survival was 263 days, or approximately 9 months, and one-year survival was 36%. Nineteen patients (41%) responded with 10 complete responses (CRs), 4 partial responses (PRs) and 5 major hematological improvements (HIs). Median time to response was 2 cycles, i.e., one cycle of decitabine and one cycle of sapacitabine (range 1-10). Twenty-seven patients (59%) received 5 or more cycles of treatment. Two dose-limiting toxicities (DLT) were observed (lung infection/sepsis, typhlitis). Thirty-day mortality from all causes was 4%. Sixty-day mortality from all causes was 13% with one death from typhlitis considered to be possibly related to decitabine by investigator assessment.

Phase 2 randomized study of sapacitabine in patients with previously untreated or first relapse AML

SEAMLESS builds on promising one year survival observed in elderly patients with AML enrolled in a Phase 2 study of single agent sapacitabine. In December 2007, we initiated a multicenter, randomized Phase 2 clinical trial of oral sapacitabine in 60 elderly patients with AML aged 70 years or older who were previously untreated or in first relapse. The Phase 2 study, led by Dr. Kantarjian, had a primary endpoint of one year survival and randomized patients to one of three dosing schedules of sapacitabine. Secondary objectives were to assess complete remission, or CR, partial remission, or PR, duration of CR or CRp, or major hematological improvement and their corresponding durations, transfusion requirements, number of hospitalized days and safety. The study used a selection design with the objective of identifying a dosing schedule among three different arms, A. 200 mg twice daily for seven days every 3-4 weeks, B. 300 mg twice daily for seven days every 3-4 weeks, and C. 400 mg twice daily for three days per week for two weeks every 3-4 weeks, which would produce a better one year survival rate in the event that all three dosing schedules were active.

In November 2012, the results from the Phase 2 study were published in The Lancet Oncology, demonstrating the safety and efficacy of sapacitabine in this patient population. Between December 27, 2007 and April 21, 2009, a total of 105 patients were enrolled and treated in the Phase 2 study. Their median age was 77 years with a range of 70-91 years. The group was comprised of a randomized cohort of 60 patients and an expanded, non-randomly assigned cohort enrolling a further 45 patients. Of the 105 patients, 86 were previously untreated and 19 in first relapse. Approximately 50% of patients had AML de novo and 50% had AML preceded by antecedent hematological disorder, or AHD, such as MDS or myeloproliferative disease, or treatment-related AML. All but one enrolled patients had intermediate or unfavorable cytogenetics. The randomized cohort of patients was assigned to one of three dosing schedules: 200 mg twice a day for 7 days (Arm A); 300 mg twice a day for 7 days (Arm B); and 400 mg twice a day for 3 days each week for 2 weeks (Arm C). All schedules were given in 28 day cycles. The 3-day dosing schedule in Arm C was selected for further clinical development in elderly patients with untreated AML. This decision was based on the schedule’s overall efficacy profile, which included a one-year survival rate of 30%, median overall survival of 213 days and durable complete remissions, or CRs, in 25% of patients. The median overall survival of patients from all arms who achieved CR was 525 days (95% C.I. 192-798). The most common grade 3-4 adverse events regardless of causality were anemia, neutropenia, thrombocytopenia, febrile neutropenia and pneumonia. Seven deaths were thought to be probably or possibly related to sapacitabine treatment.

Randomized Phase 2 clinical trial in older patients with MDS as a second-line treatment

In September 2008, we advanced sapacitabine into an open-label, multi-center, randomized Phase 2 trial as a second-line treatment in patients aged 60 or older with intermediate-2 or high-risk MDS after treatment failure of front-line hypomethylating agents, such as azacitidine and/or decitabine. The Phase 2

study randomized 63 patients aged 60 years or older with MDS of intermediate-2 (n=52) or high-risk (n=11) classification by the International Prognostic Scoring System, or IPSS, at study entry to receive sapacitabine every 4 weeks on one of 3 dosing schedules: 200 mg twice daily for 7 days (Arm G), 300 mg once daily for 7 days (Arm H), or 100 mg once daily for 5 days per week for 2 weeks (Arm I). The primary efficacy endpoint of the study is one-year survival with the objective of identifying a dosing schedule that produces a better one-year survival rate in the event that all three dosing schedules are active. All patients in the study progressed after receiving azacitidine, decitabine, or both agents. Secondary objectives are to assess the number of patients who have achieved CR or CRp, PR, hematological improvement and their corresponding durations, transfusion requirements, number of hospitalization days and safety.

In December 2013 at the 2013 ASH Meeting and Exposition, we announced primary endpoint data from the ongoing, open-label, multicenter, randomized Phase 2 trial of oral sapacitabine capsules in older patients with myelodysplastic syndromes after treatment failure of front-line hypomethylating agents, such as azacitidine and/or decitabine. The median overall survival for each arm was approximately 9.7 months for Arm G, 9.7 months for Arm H, and 7.6 months for Arm I. The median overall survival for all three arms was approximately 8.6 months. One-year survival was 38% for Arm G, 24% for Arm H, and 33% for Arm I. Nine patients had responded (2 CRs, 2 CRp, and 5 major HIs): 19% for Arm G, 10% for Arm H and 14% for Arm I and the time to response was one to four cycles. Median number of cycles was three with a range of one to over 23 and 30 patients received four or more cycles.

Additionally, 23 patients achieved stable disease lasting longer than 16 weeks. The 30 day mortality from all causes was 5% in each of the three arms and ten patients, or approximately 16%, were still alive.

We have recently completed enrollment of a patient cohort in an additional part of the MDS Phase 2 study in order to evaluate better dosing regimens. We will follow-up these additional Phase 2 patients until mature survival data become available. In parallel, we anticipate initiating a Phase 1/2 trial of sapacitabine in combination with other agents to determine safety and tolerability. We would expect to plan a Phase 2 randomized controlled trial, or RCT, of sapacitabine in combination with other agents following a review of all relevant clinical data with mature follow-up.

Median overall survival after treatment failure of front-line hypomethylating agents, such as azacitidine and/or decitabine, for patients with intermediate-2 or high- risk disease per IPSS, is reported in the literature to range between 5.9 and 4.3 months. Patients with high-risk IPSS scores also have a high probability of experiencing transformation of their MDS into AML, an aggressive form of blood cancer with typically poor survival.

Orphan Designation

European Union

During May 2008, we received designation from the EMA for sapacitabine as an orphan medicine in two separate indications: AML and MDS. The EMA’s Committee for Orphan Medicinal Products, or COMP, adopted a positive opinion on our application to designate sapacitabine as an orphan medicinal product for the indications of AML and MDS. The objective of European orphan medicines legislation is to stimulate research and development of medicinal products for rare diseases by providing incentives to industry. An orphan designation in the European Union confers a range of benefits to sponsor companies including market exclusivity for a period of 10 years, EMA scientific advice on protocol development, direct access to the centralized procedure for review of marketing authorizations, EMA fee reductions and eligibility for grant support from European agencies.

United States

In June 2010, we announced that the FDA granted orphan drug designation to our sapacitabine product candidate for the treatment of both AML and MDS. An orphan designation in the United States confers a range of benefits to sponsor companies, including market exclusivity for a period of seven years from the date of drug approval, the opportunity to apply for grant funding from the United States

government to defray costs of clinical trial expenses, tax credits for clinical research expenses and a potential waiver of the FDA’s application user fee. Orphan status is granted by the FDA to promote the development of new drug therapies for the treatment of diseases that affect fewer than 200,000 individuals in the United States.

Cyclin Dependent Kinase Inhibitor program

Cyclin Dependent Kinase Inhibitors, or CDKs, are enzymes that are central to the process of cell division and cell cycle control and play pivotal roles in cancer cell growth, survival and DNA damage repair. Inhibition of CDKs 2 and 9 may also overcome aberrant cell cycle control in certain non-malignant diseases of proliferation.

Seliciclib

Seliciclib, is a novel, orally-available, CDK2/7/9 inhibitor which has a target profile differentiated from the published target profile of other CDK inhibitors. Its selectivity is differentiated by recent publications by independent investigators which showed that seliciclib (i) is more active against NSCLC cells with K-Ras or N-Ras mutations than those with wild type Ras and (ii) overcomes resistance to letrozole in breast cancer cells caused by a particular form of cyclin E in complex with CDK2. Preclinical studies have shown that the drug works by inducing cell apoptosis, or cell suicide, in multiple phases of the cell cycle. To date, seliciclib has been evaluated in over 450 patients in several Phase 1 and 2 studies, including studies in NSCLC and NPC, and has shown signs of anti-cancer activity. We have retained worldwide rights to commercialize seliciclib.

Phase 1/2 clinical trial of seliciclib and sapacitabine in patients with advanced cancers

In an ongoing Phase 1, single-arm, dose escalation study, sapacitabine and seliciclib are administered sequentially in patients with incurable advanced solid tumors unresponsive to conventional treatment or for which no effective therapy exists. Sapacitabine is dosed twice daily for 7 days (Day 1-7) and seliciclib twice daily for 3 days (Day 8-11) for three week cycles. The primary objective of the study is to determine the maximum tolerated dose, or MTD, and recommended Phase 2 dosing schedule of sapacitabine and seliciclib administered sequentially. The secondary objective is to evaluate the antitumor activity of sequential treatment and to explore the pharmacodynamic effect of this treatment in skin and peripheral blood mononuclear cells. The study is being conducted at Dana Farber Cancer Institute in Boston and the principal investigator is Geoffrey I. Shapiro, MD with participation from other Harvard Medical School hospitals.

At the 2013 American Society of Cancer Research Annual Meeting Dr Shapiro reported that of 38 patients with incurable solid tumors and adequate organ function enrolled in the Phase 1 study, 16 were BRCA mutation positive. Four patients with BRCA-deficient pancreatic, breast or ovarian cancers had confirmed partial responses to the drug regimen. Based on available follow-up to date, three patients experienced durable partial responses, with a breast cancer patient receiving treatment over 234 weeks or 78 three-week cycles which is on-going. Researchers observed stable disease of 12 weeks or more in eight additional patients, including two BRCA positive patients with ovarian and breast cancers and whose stable disease lasted 64 and 21 weeks, respectively. The maximum tolerated doses were 50 mg sapacitabine twice daily and 1,200 mg seliciclib twice daily. Dose-limiting toxicities included reversible transaminase elevations and neutropenia. Adverse events were mild to moderate in intensity. Results of skin biopsies after treatment showed a 2.3-fold increase in DNA damage induced by sapacitabine, as measured by gamma-H2AX immunohistochemistry. Additional DNA damage occurred after treatment with seliciclib with a 0.58-fold further increase in gamma-H2AX staining.

As of December 2015, approximately 60 patients with various cancers have been enrolled, of which approximately two-thirds are BRCA positive.

Based on encouraging results from the initial patients and investigator interest the study has been expanded to evaluate an additional 20 breast cancer patients all of whom are required to test positive for BRCA in baseline biopsies. Patients will also undergo whole exome sequencing with the objective of further characterizing the genetic profiles of their tumors.

BRCA1 and BRCA2, or breast cancer susceptibility genes, are tumor suppressor genes that help ensure the stability of DNA, the cell’s genetic material, and help prevent uncontrolled cell growth. Genetic testing for BRCA-status is routinely available. BRCA mutation has been linked to predisposition to breast and ovarian cancer. According to the US National Cancer Institute, during her life time a woman has a 60% chance of developing breast cancer and 15-40% chance of developing ovarian cancer if she inherits a harmful BRCA mutation. These risks are 5 times and over 10 times more likely than for women without the mutation, respectively.

CYC065

CYC065 is a highly-selective, second generation inhibitor of CDK2 and CDK9 that causes apoptotic death of cancer cells at sub-micromolar concentrations and is bioavailable via oral and intravenous routes. Antitumor efficacy has been achieved in vivo with once a day oral dosing at well tolerated doses. Evidence from published preclinical studies show that CYC065 may benefit patients with adult and pediatric hematological malignancies, including certain AML, Acute Lymphocytic Leukemias, or ALL, Chronic Lymphocytic Leukemias, or CLL, Diffuse Large B-cell Lymphoma, or DLBCL, Multiple Myelomas or MM, and certain solid tumors, including breast and uterine cancers.

CYC065 is in an on-going, first-in-human, Phase 1 trial to assess its safety, tolerability, pharmacokinetics and pharmacodynamics in solid tumor and lymphoma patients. The trial is being conducted at the Dana Farber Cancer Institute in Boston and the principal investigator Dr Geoffrey I. Shapiro, M.D. CYC065 was selected from the Company’s drug discovery program in Dundee, Scotland and its development was supported in part by a grant award of approximately $1.9 million from the Biomedical Catalyst of the United Kingdom government.

CYC065 is mechanistically similar but has much higher dose potency, in vitro and in vivo, improved metabolic stability and longer patent protection than seliciclib, Cyclacel’s first generation CDK2/9 inhibitor. Translational biology data support development of CYC065 as a stratified medicine for solid and liquid tumors. CYC065 has been shown to reverse drug resistance associated with the addiction of cancer cells to cyclin E, a partner protein of CDK2, and inhibit CDK9-dependent oncogenic and leukemogenic pathways, including MYC and multilineage leukemia rearrangements, or MLL-r. Like seliciclib, CYC065 also represses the MCL-1-mediated survival pathway in cancer cells, leading to rapid induction of apoptosis in MCL-1 dependent cancer cells.

In 2011, independent investigators published preclinical evidence that CYC065 as a single-agent can induce tumor growth delay in HER2-positive breast cancer cells addicted to cyclin E and resistant to trastuzumab, or Herceptin®, while administration of CYC065 in combination with trastuzumab resulted in regression or sustained tumor growth inhibition.

Data presented at the American Association for Cancer Research, or AACR, 2016 Annual Meeting demonstrated the therapeutic potential of CYC065 as a targeted anti-cancer agent. The preclinical data shows that CYC065 can induce cell death, and that it combined beneficially with anti-cancer drugs from the Bcl-2 and BET inhibitor classes, in in vitro models of B-cell lymphoma, including double-hit lymphomas. The preclinical study evaluated both single-agent activity of CYC065 and combinations of CYC065 with the Bcl-2 inhibitor, venetoclax (ABT-199, Venclexta®), and BET (Bromodomain and Extra-Terminal) inhibitors in B-cell lymphoma cell lines. Short exposure to CYC065 was sufficient to downregulate MYC, an oncogene aberrantly expressed in many cancers, and Mcl-1, an anti-apoptotic member of the Bcl-2 family, and to induce cell death. CYC065 treatment had no impact on Bcl-2 levels. Combinations of CYC065 with venetoclax or BET inhibitors were both synergistic. CYC065 targets key oncogenic and survival pathways in double-hit B-cell lymphomas suggesting a therapeutic rationale for this indication.

Additionally, data presented at the 2015 Annual Meeting of the American Association of Cancer Research, or AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics demonstrated the mechanistic rationale for clinical development of CYC065 in oncology. Data showed that MLL gene status and levels of Bcl-2 family proteins correlated with sensitivity of AML cell lines to CYC065. Combination studies revealed the potential to combine CYC065 with available and experimental leukemia therapies, including cytarabine and Bcl-2 inhibitors. Potent anticancer activity of

CYC065 was demonstrated in vivo in AML xenograft models resulting in over 90% inhibition of tumor growth. The potent in vitro and in vivo anti-cancer activity, opportunity for patient stratification and the ability to combine with anti-leukemic agents suggest that CYC065 may have therapeutic potential in AML.

Data presented at the 2015 San Antonio Breast Cancer Symposium demonstrated in particular the mechanistic rationale for clinical development of CYC065 in basal-like triple negative breast cancer, or TNBC, a cancer with poor prognosis frequently associated with BRCA mutations. Molecular characteristics of TNBC include amplification or overexpression of Cyclin E, the partner protein of CDK2, and MYC. CYC065 directs a pro-apoptotic mechanism in breast cancer cell lines, which includes transcriptional down regulation of key pro-survival and oncogenic regulators, including MCL-1 and MYC.

CYC065 was shown to rapidly induce cell death in breast cancer cell lines, while transiently inducing G1 cell cycle arrest in non-malignant breast lines. CYC065’s potent anticancer activity has been confirmed in breast cancer xenograft animal models. Like seliciclib, CYC065 effectively combined with sapacitabine in breast cancer cell lines.

In 2015, independent investigators presented data demonstrating that CYC065 prolongs survival in MYCN-addicted neuroblastoma models. The study evaluated the ability of CYC065 to inhibit cell proliferation and induce apoptosis of neuroblastoma cells in vitro and in vivo. In vivo efficacy was evaluated in subcutaneous xenograft models of both MYCN-amplified and non-amplified neuroblastoma cells and the Th-MYCN genetically-engineered mouse model of neuroblastoma. The study showed that neuroblastoma cell lines with MYCN amplification and high MYCN expression levels were sensitive to the CYC065 inhibitor. CYC065 also depleted MYCN protein in a time- and dose-dependent manner, blocked neuroblastoma cell proliferation and induced apoptosis which resulted in significantly reduced tumor burdens and prolonged survival in MYCN-addicted neuroblastoma models in vivo.

Similar to palbociclib, a drug which targets CDK4/6 and the first CDK inhibitor to be recently approved by the FDA, we anticipate that CYC065 will likely be best used in combination with available anti-cancer agents. Depending on the data from the ongoing Phase 1 study, we are also interested in evaluating CYC065 in patients with hematological malignancies in light of profound signals of activity observed in preclinical studies.

PLK inhibitors

In our PLK inhibitor program we have discovered potent and selective small molecule inhibitors of PLK1, a kinase active during cell division, which target the mitotic phase of the cell cycle. At the 2012 Annual Meeting of the AACR, we reported that one of these compounds, CYC140, was selected for further preclinical development and showed potent activity and selectivity against a panel of esophageal cancer cell lines. Short drug exposure times demonstrated differential sensitivity between cancerous esophageal cells versus control, outlining the potential broad therapeutic index for CYC140 in treating esophageal cancers. PLK was discovered by Professor David Glover, our Chief Scientist. We have received a grant award of approximately $3.5 million from the Biomedical Catalyst of the United Kingdom government to complete IND-directed preclinical development of CYC140.

Aurora kinase inhibitors

Aurora kinases, or AK, are a family of serine/threonine protein kinases discovered by Professor David Glover, our Chief Scientist, which are only expressed in actively dividing cells and are crucial for the process of cell division, or mitosis. These proteins, which have been found to be over-expressed in many types of cancer, have generated significant scientific and commercial interest as cancer drug targets. Vascular endothelial growth factor receptor 2, or VEGFR2 is a receptor protein that plays a key regulatory role in the angiogenesis pathway, or blood vessel formation. VEGFR is targeted by approved drugs such as bevacizumab and sorafenib indicated for the treatment of several solid cancers, such as breast, colorectal, kidney, liver and lung.

At the Annual Meeting of the AACR 2012 we reported that collaborators tested the activity of CYC3, our novel Aurora Kinase A specific inhibitor, in pancreatic cancer cell lines and found that CYC3 acted synergistically against pancreatic cancer cell lines in combination with paclitaxel at a 10-fold lower dose

resulting in comparable anti-proliferative activity to standard paclitaxel dosing. The collaborators reported that the combination merits further investigation and has the potential for improved therapeutic index in vivo. We have completed a multicenter Phase 1 pharmacologic clinical trial of CYC116, an orally-available inhibitor of Aurora kinase A and B and VEGFR2, in patients with advanced solid tumors, but have no current plans to progress the program. We have retained worldwide rights to commercialize CYC116 and our other Aurora kinase inhibitors.

Investigator-Sponsored Trials

Preclinical results from several independent investigators suggest that cell cycle inhibitors, such as seliciclib and related molecules arrest the progress of the cell cycle and may have therapeutic benefit in the treatment of patients with autoimmune and inflammatory diseases as well as in diseases characterized by uncontrolled cell proliferation. Published data indicate potential benefit in glomerulonephritis, graft-versus-host disease, idiopathic pulmonary fibrosis, lupus nephritis, polycystic kidney disease and rheumatoid arthritis. Based on these data investigators have approached us to be provided with seliciclib so that they can evaluate it in various indications in clinical trials.

In this regard, there are on-going investigator sponsored trials, or ISTs, evaluating seliciclib in endocrinologic and inflammatory indications in patients who have failed prior treatments. In an IST at Cedars-Sinai, Los Angeles, the first patients are being treated in an on-going Phase 2 trial to evaluate seliciclib as a potential therapy for Cushing’s disease caused by pituitary tumors. There are limited options for Cushing’s disease patients today. The investigator was awarded a grant from The National Institute of Diabetes and Digestive and Kidney Diseases. In a European IST, seliciclib is being evaluated as a potential treatment for rheumatoid arthritis, or RA, where it may work for RA by targeting proliferating fibroblasts, a different type of approach than conventional RA therapies. This study is also being supported by an approximately $1.5 million grant from the United Kingdom’s Medical Research Council.

Collaboration and Licensing Agreement

On June 29, 2015, we announced the execution of a collaboration, licensing and supply agreement with ManRos Therapeutics SA, or ManRos, for the exclusive development and commercialization of our oral seliciclib capsules by ManRos as a treatment for cystic fibrosis, or CF. Among other terms of the agreement, ManRos licensed rights to our proprietary clinical data to enable clinical development of seliciclib for CF indications. The agreement provides for our supply of seliciclib investigational product for initial and later stage clinical trials of seliciclib in CF and technical assistance related to our know-how to facilitate these trials. We have received upfront payments and will receive milestone payments and tiered royalties if seliciclib is commercialized for the treatment of CF.

As with all ISTs and the collaboration and licensing agreement, we do not control the timing or conduct of such studies and will report updates as the investigators may notify us from time to time.

Recent Developments

Deficiency and Compliance Notices from The NASDAQ Stock Market and Reverse Stock Split

As previously disclosed, on February 2, 2016, we received a letter from NASDAQ’s Listing Qualifications Staff notifying us that, because we had not regained compliance with the $1.00 minimum bid price requirement for continued listing as set forth in NASDAQ Listing Rule 5550(a)(2) (the “Rule”), our common stock would be subject to delisting from NASDAQ unless the Company timely requested a hearing before a NASDAQ Listing Qualifications Panel (the “Panel”). We requested a hearing before the Panel, at which we presented a plan to regain compliance with the Rule and requested that the Panel allow us additional time to implement the plan. On April 4, 2016, the Panel rendered its written decision granting the Company until June 14, 2016 to regain compliance with the Rule.

As previously disclosed, in order to increase the per share trading price of the Company’ common stock to satisfy the $1.00 minimum bid price requirement for continued listing on The NASDAQ Capital Market, on May 26, 2016, the Company filed a certificate of amendment to its amended and restated certificate of incorporation with the Secretary of State of the State of Delaware to effect a one-for-twelve

reverse stock split of the Company’s shares of common stock. As a result of the reverse stock split, every twelve shares of the Company’s pre-reverse split common stock was combined and reclassified into one share of common stock (the “Reverse Stock Split”). The Reverse Stock Split became effective at 5:00 p.m., Eastern Time, on May 27, 2016, and the Company’s common stock began trading on the NASDAQ Capital Market on a post-split basis at the open of business on May 31, 2016. With the implementation of the Reverse Stock Split, the Company expects to regain compliance with the Rule.

All references in this prospectus to number of shares of common stock, price per share and weighted average shares of common stock have been adjusted to reflect the Reverse Stock Split on a retroactive basis for all periods presented, unless otherwise noted.

Equity Transactions

Since last reported in our Annual Report on Form 10-K for the year ended December 31, 2015, we have raised net proceeds of  $225,126 under a Controlled Equity OfferingSM sales agreement with Cantor Fitzgerald & Co.

Corporate Information

Our corporate headquarters are located at 200 Connell Drive, Suite 1500, Berkeley Heights, New Jersey, 07922, and our telephone number is (908) 517-7330. This is also where our medical and regulatory functions are located. Our research facility is located in Dundee, Scotland, which is also the center of our translational work and development programs.

Offerings Under This Prospectus

Under this prospectus, we may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants, rights or purchase contracts to purchase any of such securities, either individually or in units, with a total value of up to $100,000,000, from time to time at prices and on terms to be determined by market conditions at the time of the offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

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designation or classification;

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aggregate principal amount or aggregate offering price;

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maturity, if applicable;

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rates and times of payment of interest or dividends, if any;

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redemption, conversion or sinking fund terms, if any;

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voting or other rights, if any; and

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conversion or exercise prices, if any.

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The prospectus supplement also may add, update or change information contained in this prospectus or in documents we have incorporated by reference into this prospectus. However, no prospectus supplement will offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we offer securities through agents or underwriters, we will include in the applicable prospectus supplement:

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the names of those agents or underwriters;

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applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment options, if any; and

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the net proceeds to us.

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This prospectus may not be used to consummate a sale of any securities unless it is accompanied by a prospectus supplement.

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